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Author SHA1 Message Date
Fan Yu 085dece6cc tools/getdelays: add backward compatibility for taskstats version 
Add version checks to print_delayacct() to handle differences in struct
taskstats across kernel versions.  Field availability depends on taskstats
version (t->version), corresponding to TASKSTATS_VERSION in kernel headers
(see include/uapi/linux/taskstats.h).

Version feature mapping:
- version >= 11  - supports COMPACT statistics
- version >= 13  - supports WPCOPY statistics
- version >= 14  - supports IRQ statistics
- version >= 16  - supports *_max and *_min delay statistics

This ensures the tool works correctly with both older and newer kernel
versions by conditionally printing fields based on the reported version.

eg.1
bash# grep -r "#define TASKSTATS_VERSION" /usr/include/linux/taskstats.h
"#define TASKSTATS_VERSION       10"
bash# ./getdelays -d -p 1
CPU                 count     real total  virtual total    delay total  delay average
                     7481     3786181709     3807098291       36393725          0.005ms
IO                  count    delay total  delay average
                      369     1116046035          3.025ms
SWAP                count    delay total  delay average
                        0              0          0.000ms
RECLAIM             count    delay total  delay average
                        0              0          0.000ms
THRASHING           count    delay total  delay average
                        0              0          0.000ms

eg.2
bash# grep -r "#define TASKSTATS_VERSION" /usr/include/linux/taskstats.h
"#define TASKSTATS_VERSION       14"
bash# ./getdelays -d -p 1
CPU                 count     real total  virtual total    delay total  delay average
                    68862   163474790046   174584722267    19962496806          0.290ms
IO                  count    delay total  delay average
                        0              0          0.000ms
SWAP                count    delay total  delay average
                        0              0          0.000ms
RECLAIM             count    delay total  delay average
                        0              0          0.000ms
THRASHING           count    delay total  delay average
                        0              0          0.000ms
COMPACT             count    delay total  delay average
                        0              0          0.000ms
WPCOPY              count    delay total  delay average
                        0              0          0.000ms
IRQ                 count    delay total  delay average
                        0              0          0.000ms

Link: https://lkml.kernel.org/r/20250731225326549CttJ7g9NfjTlaqBwl015T@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Wang Yaxin <wang.yaxin@zte.com.cn>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:41 -07:00
Mike Rapoport (Microsoft) b753522bed kho: add test for kexec handover 
Testing kexec handover requires a kernel driver that will generate some
data and preserve it with KHO on the first boot and then restore that data
and verify it was preserved properly after kexec.

To facilitate such test, along with the kernel driver responsible for data
generation, preservation and restoration add a script that runs a kernel
in a VM with a minimal /init.  The /init enables KHO, loads a kernel image
for kexec and runs kexec reboot.  After the boot of the kexeced kernel,
the driver verifies that the data was properly preserved.

[rppt@kernel.org: fix section mismatch]
  Link: https://lkml.kernel.org/r/aIiRC8fXiOXKbPM_@kernel.org
Link: https://lkml.kernel.org/r/20250727083733.2590139-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:41 -07:00
fan.yu9@zte.com.cn d92dccd05a delaytop: enhance error logging and add PSI feature description 
This patch improves error diagnostics and documentation for delaytop:

1) Enhanced error logging:
   - Added explicit error messages in critical failure paths
   - Implemented BOOL_FPRINT macro for robust output handling

2) PSI feature documentation:
   - Updated header comment to reflect PSI monitoring capability
   - Improved output formatting for PSI information

System Pressure Information: (avg10/avg60/avg300/total)
CPU some:       0.0%/   0.0%/   0.0%/     345(ms)
CPU full:       0.0%/   0.0%/   0.0%/       0(ms)
Memory full:    0.0%/   0.0%/   0.0%/       0(ms)
Memory some:    0.0%/   0.0%/   0.0%/       0(ms)
IO full:        0.0%/   0.0%/   0.0%/      65(ms)
IO some:        0.0%/   0.0%/   0.0%/      79(ms)
IRQ full:       0.0%/   0.0%/   0.0%/       0(ms)

Link: https://lkml.kernel.org/r/202507281628341752gMXCMN7S-Vz_LHYHum9r@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Acked-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:41 -07:00
Colin Ian King 8c54f7e3e0 samples: Kconfig: fix spelling mistake "instancess" -> "instances" 
There is a spelling mistake in the SAMPLE_TRACE_ARRAY config. Fix it.

Link: https://lkml.kernel.org/r/20250724111715.141826-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:41 -07:00
OGAWA Hirofumi fb0e9db99e fat: fix too many log in fat_chain_add() 
This log was excessive for a serial console.  So use the ratelimited
version instead.

Link: https://lkml.kernel.org/r/87qzy611d9.fsf@mail.parknet.co.jp
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: syzbot+fa7ef54f66c189c04b73@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=fa7ef54f66c189c04b73
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:40 -07:00
WangYuli 53f433891e scripts/spelling.txt: add notifer||notifier to spelling.txt 
This typo was not listed in scripts/spelling.txt, thus it was more
difficult to detect. Add it for convenience.

Link: https://lkml.kernel.org/r/02153C05ED7B49B7+20250722073431.21983-8-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:40 -07:00
WangYuli 004f42dd90 xen/xenbus: fix typo "notifer" 
There is a spelling mistake of 'notifer' in the comment which
should be 'notifier'.

Link: https://lkml.kernel.org/r/C6633C66376C709A+20250722073431.21983-7-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:40 -07:00
WangYuli 545040384e net: mvneta: fix typo "notifer" 
There is a spelling mistake of 'notifer' in the comment which
should be 'notifier'.

Link: https://lkml.kernel.org/r/0CB4300CB6F49007+20250722073431.21983-4-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:40 -07:00
WangYuli 26197b0fd2 drm/xe: fix typo "notifer" 
There is a spelling mistake of 'notifer' in the comment which
should be 'notifier'.

Link: https://lkml.kernel.org/r/94190C5F54A19F3E+20250722073431.21983-3-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:39 -07:00
WangYuli fbedfb051a cxl: mce: fix typo "notifer" 
According to the context, "mce_notifer" should be "mce_notifier".

Link: https://lkml.kernel.org/r/E1EB1BA9FDF07D53+20250722073431.21983-2-wangyuli@uniontech.com
Fixes: 516e5bd0b6 ("cxl: Add mce notifier to emit aliased address for extended linear cache")
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:39 -07:00
WangYuli a30469cac8 KVM: x86: fix typo "notifer" 
Patch series "treewide: Fix typo "notifer"", v3.

There are some spelling mistakes of 'notifer' in comments which
should be 'notifier'.

Fix them and add it to scripts/spelling.txt.


This patch (of 8):

There are some spelling mistakes of 'notifer' which should be 'notifier'.

Link: https://lkml.kernel.org/r/576F0D85F6853074+20250722072734.19367-1-wangyuli@uniontech.com
Link: https://lkml.kernel.org/r/7F05778C3A1A9F8B+20250722073431.21983-1-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:39 -07:00
Wang Yaxin 1f03d55e5e MAINTAINERS: add maintainers for delaytop 
The delaytop tool supports showing system delays and task-level delays,
effectively identifying the top-n tasks with high latency in the system,
which is highly beneficial for improving system performance.  Wang Yaxin
and her colleague Fan Yu focus on locating system delay issues.  To
promote the thriving development of delaytop, we hope to serve as
maintainers to continuously improve it, aiming to provide a more effective
solution for system latency issues in the future.

Link: https://lkml.kernel.org/r/20250721094049958ImB8XG_imntcPqpQn1KfG@zte.com.cn
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:39 -07:00
Uros Bizjak 58b4fba81a ucount: use atomic_long_try_cmpxchg() in atomic_long_inc_below() 
Use atomic_long_try_cmpxchg() instead of
atomic_long_cmpxchg (*ptr, old, new) == old in atomic_long_inc_below().
x86 CMPXCHG instruction returns success in ZF flag, so this change saves
a compare after cmpxchg (and related move instruction in front of cmpxchg).

Also, atomic_long_try_cmpxchg implicitly assigns old *ptr value to "old"
when cmpxchg fails, enabling further code simplifications.

No functional change intended.

Link: https://lkml.kernel.org/r/20250721174610.28361-2-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Reviewed-by: Alexey Gladkov <legion@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: MengEn Sun <mengensun@tencent.com>
Cc: "Thomas Weißschuh" <linux@weissschuh.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:38 -07:00
Uros Bizjak f8cd9193b6 ucount: fix atomic_long_inc_below() argument type 
The type of u argument of atomic_long_inc_below() should be long to avoid
unwanted truncation to int.

The patch fixes the wrong argument type of an internal function to
prevent unwanted argument truncation.  It fixes an internal locking
primitive; it should not have any direct effect on userspace.

Mark said

: AFAICT there's no problem in practice because atomic_long_inc_below()
: is only used by inc_ucount(), and it looks like the value is
: constrained between 0 and INT_MAX.
: 
: In inc_ucount() the limit value is taken from
: user_namespace::ucount_max[], and AFAICT that's only written by
: sysctls, to the table setup by setup_userns_sysctls(), where
: UCOUNT_ENTRY() limits the value between 0 and INT_MAX.
: 
: This is certainly a cleanup, but there might be no functional issue in
: practice as above.

Link: https://lkml.kernel.org/r/20250721174610.28361-1-ubizjak@gmail.com
Fixes: f9c82a4ea8 ("Increase size of ucounts to atomic_long_t")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: MengEn Sun <mengensun@tencent.com>
Cc: "Thomas Weißschuh" <linux@weissschuh.net>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:38 -07:00
Alexander Graf 07d2490297 kexec: enable CMA based contiguous allocation 
When booting a new kernel with kexec_file, the kernel picks a target
location that the kernel should live at, then allocates random pages,
checks whether any of those patches magically happens to coincide with a
target address range and if so, uses them for that range.

For every page allocated this way, it then creates a page list that the
relocation code - code that executes while all CPUs are off and we are
just about to jump into the new kernel - copies to their final memory
location.  We can not put them there before, because chances are pretty
good that at least some page in the target range is already in use by the
currently running Linux environment.  Copying is happening from a single
CPU at RAM rate, which takes around 4-50 ms per 100 MiB.

All of this is inefficient and error prone.

To successfully kexec, we need to quiesce all devices of the outgoing
kernel so they don't scribble over the new kernel's memory.  We have seen
cases where that does not happen properly (*cough* GIC *cough*) and hence
the new kernel was corrupted.  This started a month long journey to root
cause failing kexecs to eventually see memory corruption, because the new
kernel was corrupted severely enough that it could not emit output to tell
us about the fact that it was corrupted.  By allocating memory for the
next kernel from a memory range that is guaranteed scribbling free, we can
boot the next kernel up to a point where it is at least able to detect
corruption and maybe even stop it before it becomes severe.  This
increases the chance for successful kexecs.

Since kexec got introduced, Linux has gained the CMA framework which can
perform physically contiguous memory mappings, while keeping that memory
available for movable memory when it is not needed for contiguous
allocations.  The default CMA allocator is for DMA allocations.

This patch adds logic to the kexec file loader to attempt to place the
target payload at a location allocated from CMA.  If successful, it uses
that memory range directly instead of creating copy instructions during
the hot phase.  To ensure that there is a safety net in case anything goes
wrong with the CMA allocation, it also adds a flag for user space to force
disable CMA allocations.

Using CMA allocations has two advantages:

  1) Faster by 4-50 ms per 100 MiB. There is no more need to copy in the
     hot phase.
  2) More robust. Even if by accident some page is still in use for DMA,
     the new kernel image will be safe from that access because it resides
     in a memory region that is considered allocated in the old kernel and
     has a chance to reinitialize that component.

Link: https://lkml.kernel.org/r/20250610085327.51817-1-graf@amazon.com
Signed-off-by: Alexander Graf <graf@amazon.com>
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Zhongkun He <hezhongkun.hzk@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:38 -07:00
Matt Fleming ed4f142f72 stackdepot: make max number of pools boot-time configurable 
We're hitting the WARN in depot_init_pool() about reaching the stack depot
limit because we have long stacks that don't dedup very well.

Introduce a new start-up parameter to allow users to set the number of
maximum stack depot pools.

Link: https://lkml.kernel.org/r/20250718153928.94229-1-matt@readmodwrite.com
Signed-off-by: Matt Fleming <mfleming@cloudflare.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:38 -07:00
Dr. David Alan Gilbert 6c6d8f8ba7 lib/xxhash: remove unused functions 
xxh32_digest() and xxh32_update() were added in 2017 in the original
xxhash commit, but have remained unused.

Remove them.

Link: https://lkml.kernel.org/r/20250716133245.243363-1-linux@treblig.org
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Dave Gilbert <linux@treblig.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:37 -07:00
Andrew Morton fefbeed8c6 init/Kconfig: restore CONFIG_BROKEN help text 
Linus added it in 2003, it later was removed.  Put it back.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-08-02 12:01:37 -07:00
Herbert Xu a9ed4422ad lib/raid6: update recov_rvv.c zero page usage 
Update lib/raid6/recov_rvv.c, for 1857fcc847 ("lib/raid6: replace custom
zero page with ZERO_PAGE"), per Klara.

Link: https://lkml.kernel.org/r/aFkUnXWtxcgOTVkw@gondor.apana.org.au
Fixes: 1857fcc847 ("lib/raid6: replace custom zero page with ZERO_PAGE")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Song Liu <song@kernel.org>
Cc: Yu Kuai <yukuai3@huawei.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:29 -07:00
Wang Yaxin 320bf1709a docs: update docs after introducing delaytop 
The "getdelays" can only display the latency of a single task by
specifying a PID, we introduce the "delaytop" with the following
capabilities:

1. system view: monitors latency metrics (CPU, I/O, memory, IRQ, etc.)
   for all system processes

2. supports field-based sorting (e.g., default sort by CPU latency in
   descending order)

3. dynamic interactive interface: focus on specific processes with
   --pid; limit displayed entries with --processes 20; control monitoring
   duration with --iterations;

Link: https://lkml.kernel.org/r/2025071013514177028RdjISjqeIOnTCRvGAwy@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Jiang Kun <jiang.kun2@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Peilin He <he.peilin@zte.com.cn>
Cc: Qiang Tu <tu.qiang35@zte.com.cn>
Cc: wangyong <wang.yong12@zte.com.cn>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Yunkai Zhang <zhang.yunkai@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:29 -07:00
Wang Yaxin 6b47c9f8ee delaytop: add psi info to show system delay 
Support showing whole delay of system by reading PSI, just like the first
few lines of information output by the top command.  the output of
delaytop includes both system-wide delay and delay of individual tasks,
providing a more comprehensive reflection of system latency status.

Use case
========
bash# ./delaytop
System Pressure Information: (avg10/avg60/avg300/total)
CPU:    full:    0.0%/   0.0%/   0.0%/0           some:    0.1%/   0.0%/   0.0%/14216596
Memory: full:    0.0%/   0.0%/   0.0%/34010659    some:    0.0%/   0.0%/   0.0%/35406492
IO:     full:    0.1%/   0.0%/   0.0%/51029453    some:    0.1%/   0.0%/   0.0%/55330465
IRQ:    full:    0.0%/   0.0%/   0.0%/0

Top 20 processes (sorted by CPU delay):

  PID   TGID  COMMAND            CPU(ms)  IO(ms)        SWAP(ms) RCL(ms) THR(ms)  CMP(ms)  WP(ms)  IRQ(ms)
---------------------------------------------------------------------------------------------
   32     32  kworker/2:0H-sy   23.65     0.00     0.00     0.00    0.00     0.00     0.00     0.00
  497    497  kworker/R-scsi_    1.20     0.00     0.00     0.00    0.00     0.00     0.00     0.00
  495    495  kworker/R-scsi_    1.13     0.00     0.00     0.00    0.00     0.00     0.00     0.00
  494    494  scsi_eh_0          1.12     0.00     0.00     0.00    0.00     0.00     0.00     0.00
  485    485  kworker/R-ata_s    0.90     0.00     0.00     0.00    0.00     0.00     0.00     0.00
  574    574  kworker/R-kdmfl    0.36     0.00     0.00     0.00    0.00     0.00     0.00     0.00
   34     34  idle_inject/3      0.33     0.00     0.00     0.00    0.00     0.00     0.00     0.00
 1123   1123  nde-netfilter      0.28     0.00     0.00     0.00    0.00     0.00     0.00     0.00
   60     60  ksoftirqd/7        0.25     0.00     0.00     0.00    0.00     0.00     0.00     0.00
  114    114  kworker/0:2-cgr    0.25     0.00     0.00     0.00    0.00     0.00     0.00     0.00
  496    496  scsi_eh_1          0.24     0.00     0.00     0.00    0.00     0.00     0.00     0.00
   51     51  cpuhp/6            0.24     0.00     0.00     0.00    0.00     0.00     0.00     0.00
 1667   1667  atd                0.24     0.00     0.00     0.00    0.00     0.00     0.00     0.00
   45     45  cpuhp/5            0.23     0.00     0.00     0.00    0.00     0.00     0.00     0.00
 1102   1102  nde-backupservi    0.22     0.00     0.00     0.00    0.00     0.00     0.00     0.00
 1098   1098  systemsettings     0.21     0.00     0.00     0.00    0.00     0.00     0.00     0.00
 1100   1100  audit-monitor      0.20     0.00     0.00     0.00    0.00     0.00     0.00     0.00
   53     53  migration/6        0.20     0.00     0.00     0.00    0.00     0.00     0.00     0.00
 1482   1482  sshd               0.19     0.00     0.00     0.00    0.00     0.00     0.00     0.00
   39     39  cpuhp/4            0.19     0.00     0.00     0.00    0.00     0.00     0.00     0.00

Link: https://lkml.kernel.org/r/20250710135451340_5pOgpIFi0M5AE7H44W1D@zte.com.cn
Co-developed-by: Fan Yu <fan.yu9@zte.com.cn>
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Jiang Kun <jiang.kun2@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Peilin He <he.peilin@zte.com.cn>
Cc: Qiang Tu <tu.qiang35@zte.com.cn>
Cc: wangyong <wang.yong12@zte.com.cn>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Yunkai Zhang <zhang.yunkai@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:29 -07:00
WangYuli 599579e857 selftests/thermal: remove duplicate newlines in perror calls 
perror() automatically appends a newline character, so the explicit '\n'
in the format strings is redundant and results in duplicate newlines in
the output.

Remove the redundant '\n' characters from perror() calls in
workload_hint_test.c to fix the formatting.

Link: https://lkml.kernel.org/r/F482FB1EC020000C+20250710134751.306096-1-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Cc: Guan Wentao <guanwentao@uniontech.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:28 -07:00
WangYuli 813b468088 selftests/thermal: remove duplicate sprintf() call in workload_hint_test 
Remove redundant sprintf() call that was duplicating the same operation of
formatting delay_str with argv[1].

Link: https://lkml.kernel.org/r/6338CD0E839B770B+20250710130412.284531-1-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Cc: Guan Wentao <guanwentao@uniontech.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:28 -07:00
Kuan-Wei Chiu 36e2241687 riscv: optimize gcd() performance on RISC-V without Zbb extension 
The binary GCD implementation uses FFS (find first set), which benefits
from hardware support for the ctz instruction, provided by the Zbb
extension on RISC-V.  Without Zbb, this results in slower
software-emulated behavior.

Previously, RISC-V always used the binary GCD, regardless of actual
hardware support.  This patch improves runtime efficiency by disabling the
efficient_ffs_key static branch when Zbb is either not enabled in the
kernel (config) or not supported on the executing CPU.  This selects the
odd-even GCD implementation, which is faster in the absence of efficient
FFS.

This change ensures the most suitable GCD algorithm is chosen dynamically
based on actual hardware capabilities.

Link: https://lkml.kernel.org/r/20250606134758.1308400-4-visitorckw@gmail.com
Co-developed-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:28 -07:00
Kuan-Wei Chiu 26b537edc5 riscv: optimize gcd() code size when CONFIG_RISCV_ISA_ZBB is disabled 
The binary GCD implementation depends on efficient ffs(), which on RISC-V
requires hardware support for the Zbb extension.  When
CONFIG_RISCV_ISA_ZBB is not enabled, the kernel will never use binary GCD,
as runtime logic will always fall back to the odd-even implementation.

To avoid compiling unused code and reduce code size, select
CONFIG_CPU_NO_EFFICIENT_FFS when CONFIG_RISCV_ISA_ZBB is not set.

$ ./scripts/bloat-o-meter ./lib/math/gcd.o.old ./lib/math/gcd.o.new
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-274 (-274)
Function                                     old     new   delta
gcd                                          360      86    -274
Total: Before=384, After=110, chg -71.35%

Link: https://lkml.kernel.org/r/20250606134758.1308400-3-visitorckw@gmail.com
Co-developed-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:28 -07:00
Kuan-Wei Chiu b3d5fd6f82 lib/math/gcd: use static key to select implementation at runtime 
Patch series "Optimize GCD performance on RISC-V by selecting
implementation at runtime", v3.

The current implementation of gcd() selects between the binary GCD and the
odd-even GCD algorithm at compile time, depending on whether
CONFIG_CPU_NO_EFFICIENT_FFS is set.  On platforms like RISC-V, however,
this compile-time decision can be misleading: even when the compiler emits
ctz instructions based on the assumption that they are efficient (as is
the case when CONFIG_RISCV_ISA_ZBB is enabled), the actual hardware may
lack support for the Zbb extension.  In such cases, ffs() falls back to a
software implementation at runtime, making the binary GCD algorithm
significantly slower than the odd-even variant.

To address this, we introduce a static key to allow runtime selection
between the binary and odd-even GCD implementations.  On RISC-V, the
kernel now checks for Zbb support during boot.  If Zbb is unavailable, the
static key is disabled so that gcd() consistently uses the more efficient
odd-even algorithm in that scenario.  Additionally, to further reduce code
size, we select CONFIG_CPU_NO_EFFICIENT_FFS automatically when
CONFIG_RISCV_ISA_ZBB is not enabled, avoiding compilation of the unused
binary GCD implementation entirely on systems where it would never be
executed.

This series ensures that the most efficient GCD algorithm is used in
practice and avoids compiling unnecessary code based on hardware
capabilities and kernel configuration.


This patch (of 3):

On platforms like RISC-V, the compiler may generate hardware FFS
instructions even if the underlying CPU does not actually support them. 
Currently, the GCD implementation is chosen at compile time based on
CONFIG_CPU_NO_EFFICIENT_FFS, which can result in suboptimal behavior on
such systems.

Introduce a static key, efficient_ffs_key, to enable runtime selection
between the binary GCD (using ffs) and the odd-even GCD implementation. 
This allows the kernel to default to the faster binary GCD when FFS is
efficient, while retaining the ability to fall back when needed.

Link: https://lkml.kernel.org/r/20250606134758.1308400-1-visitorckw@gmail.com
Link: https://lkml.kernel.org/r/20250606134758.1308400-2-visitorckw@gmail.com
Co-developed-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:28 -07:00
Ivan Pravdin 08eabe4b9e ocfs2: avoid potential ABBA deadlock by reordering tl_inode lock 
In ocfs2_move_extent(), tl_inode is currently locked after the global
bitmap inode.  However, in ocfs2_flush_truncate_log(), the lock order is
reversed: tl_inode is locked first, followed by the global bitmap inode.

This creates a classic ABBA deadlock scenario if two threads attempt these
operations concurrently and acquire the locks in different orders.

To prevent this, move the tl_inode locking earlier in ocfs2_move_extent(),
so that it always precedes the global bitmap inode lock.

No functional changes beyond lock ordering.

Link: https://lkml.kernel.org/r/20250708020640.387741-1-ipravdin.official@gmail.com
Reported-by: syzbot+6bf948e47f9bac7aacfa@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67d5645c.050a0220.1dc86f.0004.GAE@google.com/
Signed-off-by: Ivan Pravdin <ipravdin.official@gmail.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:27 -07:00
Colin Ian King 97103dcec2 squashfs: fix incorrect argument to sizeof in kmalloc_array call 
The sizeof(void *) is the incorrect argument in the kmalloc_array call, it
best to fix this by using sizeof(*cache_folios) instead.

Fortunately the sizes of void* and folio* happen to be the same, so this
has not shown up as a run time issue.

[akpm@linux-foundation.org: fix build]
Link: https://lkml.kernel.org/r/20250708142604.1891156-1-colin.i.king@gmail.com
Fixes: 2e227ff5e2 ("squashfs: add optional full compressed block caching")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Chanho Min <chanho.min@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:27 -07:00
Colin Ian King c0f98be69f squashfs: replace ;; with ; and end of fi declaration 
There is an extraneous ; after a declaration, remove it.

Link: https://lkml.kernel.org/r/20250708114900.1883130-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:27 -07:00
Ivan Pravdin 44acc46d18 ocfs2: avoid NULL pointer dereference in dx_dir_lookup_rec() 
When a directory entry is not found, ocfs2_dx_dir_lookup_rec() prints an
error message that unconditionally dereferences the 'rec' pointer. 
However, if 'rec' is NULL, this leads to a NULL pointer dereference and a
kernel panic.

Add an explicit check empty extent list to avoid dereferencing NULL
'rec' pointer.

Link: https://lkml.kernel.org/r/20250708001009.372263-1-ipravdin.official@gmail.com
Reported-by: syzbot+20282c1b2184a857ac4c@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67cd7e29.050a0220.e1a89.0007.GAE@google.com/
Signed-off-by: Ivan Pravdin <ipravdin.official@gmail.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:27 -07:00
Ahelenia Ziemiańska 988f451ecb ocfs2/dlm: fix "take a while" typo 
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:26 -07:00
Lillian Berry 98aa4d5d24 init/main.c: add warning when file specified in rdinit is inaccessible 
Avoid silently ignoring the initramfs when the file specified in rdinit is
not usable.  This prints an error that clearly explains the issue (file
was not found, vs initramfs was not found).

Link: https://lkml.kernel.org/r/20250707091411.1412681-1-lillian@star-ark.net
Signed-off-by: Lillian Berry <lillian@star-ark.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:26 -07:00
Zi Li 4efec6c091 samples: enhance hung_task detector test with read-write semaphore support 
Extend the hung_task detector test module to include read-write semaphore
support alongside existing mutex and semaphore tests.  This module now
creates additional debugfs files under <debugfs>/hung_task, namely
'rw_semaphore_read' and 'rw_semaphore_write', in addition to 'mutex' and
'semaphore'.  Reading these files with multiple processes triggers a
prolonged sleep (256 seconds) while holding the respective lock, enabling
hung_task detector testing for various locking mechanisms.

This change builds on the extensible hung_task_tests module, adding
read-write semaphore functionality to improve test coverage for kernel
locking primitives.  The implementation ensures proper lock handling and
includes checks to prevent redundant data reads.

Usage is:

        > cd /sys/kernel/debug/hung_task
        > cat mutex & cat mutex           # Test mutex blocking
        > cat semaphore & cat semaphore   # Test semaphore blocking
        > cat rw_semaphore_write \
            & cat rw_semaphore_read       # Test rwsem blocking
        > cat rw_semaphore_write \
            & cat rw_semaphore_write      # Test rwsem blocking

Update the Kconfig description to reflect the addition of read-write
semaphore debugfs files.

Link: https://lkml.kernel.org/r/20250627072924.36567-4-lance.yang@linux.dev
Signed-off-by: Zi Li <zi.li@linux.dev>
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Stultz <jstultz@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Mingzhe Yang <mingzhe.yang@ly.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tomasz Figa <tfiga@chromium.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yongliang Gao <leonylgao@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:26 -07:00
Lance Yang 77da18de55 hung_task: extend hung task blocker tracking to rwsems 
Inspired by mutex blocker tracking[1], and having already extended it to
semaphores, let's now add support for reader-writer semaphores (rwsems).

The approach is simple: when a task enters TASK_UNINTERRUPTIBLE while
waiting for an rwsem, we just call hung_task_set_blocker().  The hung task
detector can then query the rwsem's owner to identify the lock holder.

Tracking works reliably for writers, as there can only be a single writer
holding the lock, and its task struct is stored in the owner field.

The main challenge lies with readers.  The owner field points to only one
of many concurrent readers, so we might lose track of the blocker if that
specific reader unlocks, even while others remain.  This is not a
significant issue, however.  In practice, long-lasting lock contention is
almost always caused by a writer.  Therefore, reliably tracking the writer
is the primary goal of this patch series ;)

With this change, the hung task detector can now show blocker task's info
like below:

[Fri Jun 27 15:21:34 2025] INFO: task cat:28631 blocked for more than 122 seconds.
[Fri Jun 27 15:21:34 2025]       Tainted: G S                  6.16.0-rc3 #8
[Fri Jun 27 15:21:34 2025] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[Fri Jun 27 15:21:34 2025] task:cat             state:D stack:0     pid:28631 tgid:28631 ppid:28501  task_flags:0x400000 flags:0x00004000
[Fri Jun 27 15:21:34 2025] Call Trace:
[Fri Jun 27 15:21:34 2025]  <TASK>
[Fri Jun 27 15:21:34 2025]  __schedule+0x7c7/0x1930
[Fri Jun 27 15:21:34 2025]  ? __pfx___schedule+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? policy_nodemask+0x215/0x340
[Fri Jun 27 15:21:34 2025]  ? _raw_spin_lock_irq+0x8a/0xe0
[Fri Jun 27 15:21:34 2025]  ? __pfx__raw_spin_lock_irq+0x10/0x10
[Fri Jun 27 15:21:34 2025]  schedule+0x6a/0x180
[Fri Jun 27 15:21:34 2025]  schedule_preempt_disabled+0x15/0x30
[Fri Jun 27 15:21:34 2025]  rwsem_down_read_slowpath+0x55e/0xe10
[Fri Jun 27 15:21:34 2025]  ? __pfx_rwsem_down_read_slowpath+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? __pfx___might_resched+0x10/0x10
[Fri Jun 27 15:21:34 2025]  down_read+0xc9/0x230
[Fri Jun 27 15:21:34 2025]  ? __pfx_down_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? __debugfs_file_get+0x14d/0x700
[Fri Jun 27 15:21:34 2025]  ? __pfx___debugfs_file_get+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? handle_pte_fault+0x52a/0x710
[Fri Jun 27 15:21:34 2025]  ? selinux_file_permission+0x3a9/0x590
[Fri Jun 27 15:21:34 2025]  read_dummy_rwsem_read+0x4a/0x90
[Fri Jun 27 15:21:34 2025]  full_proxy_read+0xff/0x1c0
[Fri Jun 27 15:21:34 2025]  ? rw_verify_area+0x6d/0x410
[Fri Jun 27 15:21:34 2025]  vfs_read+0x177/0xa50
[Fri Jun 27 15:21:34 2025]  ? __pfx_vfs_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? fdget_pos+0x1cf/0x4c0
[Fri Jun 27 15:21:34 2025]  ksys_read+0xfc/0x1d0
[Fri Jun 27 15:21:34 2025]  ? __pfx_ksys_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  do_syscall_64+0x66/0x2d0
[Fri Jun 27 15:21:34 2025]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f3f8faefb40
[Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffdeda5ab98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f3f8faefb40
[Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 00000000010fa000 RDI: 0000000000000003
[Fri Jun 27 15:21:34 2025] RBP: 00000000010fa000 R08: 0000000000000000 R09: 0000000000010fff
[Fri Jun 27 15:21:34 2025] R10: 00007ffdeda59fe0 R11: 0000000000000246 R12: 00000000010fa000
[Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff
[Fri Jun 27 15:21:34 2025]  </TASK>
[Fri Jun 27 15:21:34 2025] INFO: task cat:28631 <reader> blocked on an rw-semaphore likely owned by task cat:28630 <writer>
[Fri Jun 27 15:21:34 2025] task:cat             state:S stack:0     pid:28630 tgid:28630 ppid:28501  task_flags:0x400000 flags:0x00004000
[Fri Jun 27 15:21:34 2025] Call Trace:
[Fri Jun 27 15:21:34 2025]  <TASK>
[Fri Jun 27 15:21:34 2025]  __schedule+0x7c7/0x1930
[Fri Jun 27 15:21:34 2025]  ? __pfx___schedule+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? __mod_timer+0x304/0xa80
[Fri Jun 27 15:21:34 2025]  schedule+0x6a/0x180
[Fri Jun 27 15:21:34 2025]  schedule_timeout+0xfb/0x230
[Fri Jun 27 15:21:34 2025]  ? __pfx_schedule_timeout+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? __pfx_process_timeout+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? down_write+0xc4/0x140
[Fri Jun 27 15:21:34 2025]  msleep_interruptible+0xbe/0x150
[Fri Jun 27 15:21:34 2025]  read_dummy_rwsem_write+0x54/0x90
[Fri Jun 27 15:21:34 2025]  full_proxy_read+0xff/0x1c0
[Fri Jun 27 15:21:34 2025]  ? rw_verify_area+0x6d/0x410
[Fri Jun 27 15:21:34 2025]  vfs_read+0x177/0xa50
[Fri Jun 27 15:21:34 2025]  ? __pfx_vfs_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? fdget_pos+0x1cf/0x4c0
[Fri Jun 27 15:21:34 2025]  ksys_read+0xfc/0x1d0
[Fri Jun 27 15:21:34 2025]  ? __pfx_ksys_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  do_syscall_64+0x66/0x2d0
[Fri Jun 27 15:21:34 2025]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f8f288efb40
[Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffffb631038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f8f288efb40
[Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 000000002a4b5000 RDI: 0000000000000003
[Fri Jun 27 15:21:34 2025] RBP: 000000002a4b5000 R08: 0000000000000000 R09: 0000000000010fff
[Fri Jun 27 15:21:34 2025] R10: 00007ffffb630460 R11: 0000000000000246 R12: 000000002a4b5000
[Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff
[Fri Jun 27 15:21:34 2025]  </TASK>

[1] https://lore.kernel.org/all/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com/

Link: https://lkml.kernel.org/r/20250627072924.36567-3-lance.yang@linux.dev
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Stultz <jstultz@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Mingzhe Yang <mingzhe.yang@ly.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tomasz Figa <tfiga@chromium.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yongliang Gao <leonylgao@tencent.com>
Cc: Zi Li <zi.li@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:26 -07:00
Lance Yang ae2da51def locking/rwsem: make owner helpers globally available 
Patch series "extend hung task blocker tracking to rwsems".

Inspired by mutex blocker tracking[1], and having already extended it to
semaphores, let's now add support for reader-writer semaphores (rwsems).

The approach is simple: when a task enters TASK_UNINTERRUPTIBLE while
waiting for an rwsem, we just call hung_task_set_blocker().  The hung task
detector can then query the rwsem's owner to identify the lock holder.

Tracking works reliably for writers, as there can only be a single writer
holding the lock, and its task struct is stored in the owner field.

The main challenge lies with readers.  The owner field points to only one
of many concurrent readers, so we might lose track of the blocker if that
specific reader unlocks, even while others remain.  This is not a
significant issue, however.  In practice, long-lasting lock contention is
almost always caused by a writer.  Therefore, reliably tracking the writer
is the primary goal of this patch series ;)

With this change, the hung task detector can now show blocker task's info
like below:

[Fri Jun 27 15:21:34 2025] INFO: task cat:28631 blocked for more than 122 seconds.
[Fri Jun 27 15:21:34 2025]       Tainted: G S                  6.16.0-rc3 #8
[Fri Jun 27 15:21:34 2025] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[Fri Jun 27 15:21:34 2025] task:cat             state:D stack:0     pid:28631 tgid:28631 ppid:28501  task_flags:0x400000 flags:0x00004000
[Fri Jun 27 15:21:34 2025] Call Trace:
[Fri Jun 27 15:21:34 2025]  <TASK>
[Fri Jun 27 15:21:34 2025]  __schedule+0x7c7/0x1930
[Fri Jun 27 15:21:34 2025]  ? __pfx___schedule+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? policy_nodemask+0x215/0x340
[Fri Jun 27 15:21:34 2025]  ? _raw_spin_lock_irq+0x8a/0xe0
[Fri Jun 27 15:21:34 2025]  ? __pfx__raw_spin_lock_irq+0x10/0x10
[Fri Jun 27 15:21:34 2025]  schedule+0x6a/0x180
[Fri Jun 27 15:21:34 2025]  schedule_preempt_disabled+0x15/0x30
[Fri Jun 27 15:21:34 2025]  rwsem_down_read_slowpath+0x55e/0xe10
[Fri Jun 27 15:21:34 2025]  ? __pfx_rwsem_down_read_slowpath+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? __pfx___might_resched+0x10/0x10
[Fri Jun 27 15:21:34 2025]  down_read+0xc9/0x230
[Fri Jun 27 15:21:34 2025]  ? __pfx_down_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? __debugfs_file_get+0x14d/0x700
[Fri Jun 27 15:21:34 2025]  ? __pfx___debugfs_file_get+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? handle_pte_fault+0x52a/0x710
[Fri Jun 27 15:21:34 2025]  ? selinux_file_permission+0x3a9/0x590
[Fri Jun 27 15:21:34 2025]  read_dummy_rwsem_read+0x4a/0x90
[Fri Jun 27 15:21:34 2025]  full_proxy_read+0xff/0x1c0
[Fri Jun 27 15:21:34 2025]  ? rw_verify_area+0x6d/0x410
[Fri Jun 27 15:21:34 2025]  vfs_read+0x177/0xa50
[Fri Jun 27 15:21:34 2025]  ? __pfx_vfs_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? fdget_pos+0x1cf/0x4c0
[Fri Jun 27 15:21:34 2025]  ksys_read+0xfc/0x1d0
[Fri Jun 27 15:21:34 2025]  ? __pfx_ksys_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  do_syscall_64+0x66/0x2d0
[Fri Jun 27 15:21:34 2025]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f3f8faefb40
[Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffdeda5ab98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f3f8faefb40
[Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 00000000010fa000 RDI: 0000000000000003
[Fri Jun 27 15:21:34 2025] RBP: 00000000010fa000 R08: 0000000000000000 R09: 0000000000010fff
[Fri Jun 27 15:21:34 2025] R10: 00007ffdeda59fe0 R11: 0000000000000246 R12: 00000000010fa000
[Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff
[Fri Jun 27 15:21:34 2025]  </TASK>
[Fri Jun 27 15:21:34 2025] INFO: task cat:28631 <reader> blocked on an rw-semaphore likely owned by task cat:28630 <writer>
[Fri Jun 27 15:21:34 2025] task:cat             state:S stack:0     pid:28630 tgid:28630 ppid:28501  task_flags:0x400000 flags:0x00004000
[Fri Jun 27 15:21:34 2025] Call Trace:
[Fri Jun 27 15:21:34 2025]  <TASK>
[Fri Jun 27 15:21:34 2025]  __schedule+0x7c7/0x1930
[Fri Jun 27 15:21:34 2025]  ? __pfx___schedule+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? __mod_timer+0x304/0xa80
[Fri Jun 27 15:21:34 2025]  schedule+0x6a/0x180
[Fri Jun 27 15:21:34 2025]  schedule_timeout+0xfb/0x230
[Fri Jun 27 15:21:34 2025]  ? __pfx_schedule_timeout+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? __pfx_process_timeout+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? down_write+0xc4/0x140
[Fri Jun 27 15:21:34 2025]  msleep_interruptible+0xbe/0x150
[Fri Jun 27 15:21:34 2025]  read_dummy_rwsem_write+0x54/0x90
[Fri Jun 27 15:21:34 2025]  full_proxy_read+0xff/0x1c0
[Fri Jun 27 15:21:34 2025]  ? rw_verify_area+0x6d/0x410
[Fri Jun 27 15:21:34 2025]  vfs_read+0x177/0xa50
[Fri Jun 27 15:21:34 2025]  ? __pfx_vfs_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  ? fdget_pos+0x1cf/0x4c0
[Fri Jun 27 15:21:34 2025]  ksys_read+0xfc/0x1d0
[Fri Jun 27 15:21:34 2025]  ? __pfx_ksys_read+0x10/0x10
[Fri Jun 27 15:21:34 2025]  do_syscall_64+0x66/0x2d0
[Fri Jun 27 15:21:34 2025]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[Fri Jun 27 15:21:34 2025] RIP: 0033:0x7f8f288efb40
[Fri Jun 27 15:21:34 2025] RSP: 002b:00007ffffb631038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[Fri Jun 27 15:21:34 2025] RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f8f288efb40
[Fri Jun 27 15:21:34 2025] RDX: 0000000000010000 RSI: 000000002a4b5000 RDI: 0000000000000003
[Fri Jun 27 15:21:34 2025] RBP: 000000002a4b5000 R08: 0000000000000000 R09: 0000000000010fff
[Fri Jun 27 15:21:34 2025] R10: 00007ffffb630460 R11: 0000000000000246 R12: 000000002a4b5000
[Fri Jun 27 15:21:34 2025] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff
[Fri Jun 27 15:21:34 2025]  </TASK>


This patch (of 3):

In preparation for extending blocker tracking to support rwsems, make the
rwsem_owner() and is_rwsem_reader_owned() helpers globally available for
determining if the blocker is a writer or one of the readers.

Additionally, a stale owner pointer in a reader-owned rwsem can lead to
false positives in blocker tracking when CONFIG_DETECT_HUNG_TASK_BLOCKER
is enabled.  To mitigate this, clear the owner field on the reader unlock
path, similar to what CONFIG_DEBUG_RWSEMS does.  A NULL owner is better
than a stale one for diagnostics.

Link: https://lkml.kernel.org/r/20250627072924.36567-1-lance.yang@linux.dev
Link: https://lkml.kernel.org/r/20250627072924.36567-2-lance.yang@linux.dev
Link: https://lore.kernel.org/all/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com/ [1]
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Stultz <jstultz@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Mingzhe Yang <mingzhe.yang@ly.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tomasz Figa <tfiga@chromium.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yongliang Gao <leonylgao@tencent.com>
Cc: Zi Li <zi.li@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:25 -07:00
Easwar Hariharan 249e7ced72 coccinelle: misc: secs_to_jiffies: implement context and report modes 
As requested by Ricardo and Jakub, implement report and context modes for
the secs_to_jiffies Coccinelle script.  While here, add the option to look
for opportunities to use secs_to_jiffies() in headers.

Link: https://lkml.kernel.org/r/20250703225145.152288-1-eahariha@linux.microsoft.com
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
Closes: https://lore.kernel.org/all/20250129-secs_to_jiffles-v1-1-35a5e16b9f03@chromium.org/
Closes: https://lore.kernel.org/all/20250221162107.409ae333@kernel.org/
Tested-by: Ricardo Ribalda <ribalda@chromium.org>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Nicolas Palix <nicolas.palix@imag.fr>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:25 -07:00
Feng Tang ee13240cd7 panic: add note that panic_print sysctl interface is deprecated 
Add a dedicated core parameter 'panic_console_replay' for controlling
console replay, and add note that 'panic_print' sysctl interface will be
obsoleted by 'panic_sys_info' and 'panic_console_replay'.  When it
happens, the SYS_INFO_PANIC_CONSOLE_REPLAY can be removed as well.

Link: https://lkml.kernel.org/r/20250703021004.42328-6-feng.tang@linux.alibaba.com
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:25 -07:00
Feng Tang 9743d12d0c panic: add 'panic_sys_info=' setup option for kernel cmdline 
'panic_sys_info=' sysctl interface is already added for runtime setting. 
Add counterpart kernel cmdline option for boottime setting.

Link: https://lkml.kernel.org/r/20250703021004.42328-5-feng.tang@linux.alibaba.com
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:24 -07:00
Feng Tang d747755917 panic: add 'panic_sys_info' sysctl to take human readable string parameter 
Bitmap definition for 'panic_print' is hard to remember and decode.  Add
'panic_sys_info='sysctl to take human readable string like
"tasks,mem,timers,locks,ftrace,..." and translate it into bitmap.

The detailed mapping is:
	SYS_INFO_TASKS		"tasks"
	SYS_INFO_MEM		"mem"
	SYS_INFO_TIMERS		"timers"
	SYS_INFO_LOCKS		"locks"
	SYS_INFO_FTRACE		"ftrace"
	SYS_INFO_ALL_CPU_BT	"all_bt"
	SYS_INFO_BLOCKED_TASKS	"blocked_tasks"

[nathan@kernel.org: add __maybe_unused to sys_info_avail]
  Link: https://lkml.kernel.org/r/20250708-fix-clang-sys_info_avail-warning-v1-1-60d239eacd64@kernel.org
Link: https://lkml.kernel.org/r/20250703021004.42328-4-feng.tang@linux.alibaba.com
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:24 -07:00
Feng Tang b76e89e50f panic: generalize panic_print's function to show sys info 
'panic_print' was introduced to help debugging kernel panic by dumping
different kinds of system information like tasks' call stack, memory,
ftrace buffer, etc.  Actually this function could also be used to help
debugging other cases like task-hung, soft/hard lockup, etc.  where user
may need the snapshot of system info at that time.

Extract system info dump function related code from panic.c to separate
file sys_info.[ch], for wider usage by other kernel parts for debugging.

Also modify the macro names about singulars/plurals.

Link: https://lkml.kernel.org/r/20250703021004.42328-3-feng.tang@linux.alibaba.com
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:24 -07:00
Feng Tang 261743b013 panic: clean up code for console replay 
Patch series "generalize panic_print's dump function to be used by other
kernel parts", v3.

When working on kernel stability issues, panic, task-hung and
software/hardware lockup are frequently met.  And to debug them, user may
need lots of system information at that time, like task call stacks, lock
info, memory info etc.  

panic case already has panic_print_sys_info() for this purpose, and has a
'panic_print' bitmask to control what kinds of information is needed,
which is also helpful to debug other task-hung and lockup cases.

So this patchset extracts the function out to a new file 'lib/sys_info.c',
and makes it available for other cases which also need to dump system info
for debugging.  

Also as suggested by Petr Mladek, add 'panic_sys_info=' interface to take
human readable string like "tasks,mem,locks,timers,ftrace,....", and
eventually obsolete the current 'panic_print' bitmap interface.

In RFC and V1 version, hung_task and SW/HW watchdog modules are enabled
with the new sys_info dump interface.  In v2, they are kept out for better
review of current change, and will be posted later.  

Locally these have been used in our bug chasing for stability issues and
was proven helpful.

Many thanks to Petr Mladek for great suggestions on both the code and
architectures!


This patch (of 5):

Currently the panic_print_sys_info() was called twice with different
parameters to handle console replay case, which is kind of confusing.

Add panic_console_replay() explicitly and rename
'PANIC_PRINT_ALL_PRINTK_MSG' to 'PANIC_CONSOLE_REPLAY', to make the code
straightforward.  The related kernel document is also updated.

Link: https://lkml.kernel.org/r/20250703021004.42328-1-feng.tang@linux.alibaba.com
Link: https://lkml.kernel.org/r/20250703021004.42328-2-feng.tang@linux.alibaba.com
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:24 -07:00
Jiri Bohac bf8be1c361 x86: implement crashkernel cma reservation 
Implement the crashkernel CMA reservation for x86:
- enable parsing of the cma suffix by parse_crashkernel()
- reserve memory with reserve_crashkernel_cma()
- add the CMA-reserved ranges to the e820 map for the crash kernel
- exclude the CMA-reserved ranges from vmcore

Link: https://lkml.kernel.org/r/aEqp1LD2og4QeBw9@dwarf.suse.cz
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Donald Dutile <ddutile@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Tao Liu <ltao@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:23 -07:00
Jiri Bohac e1280f3071 kdump: wait for DMA to finish when using CMA 
When re-using the CMA area for kdump there is a risk of pending DMA into
pinned user pages in the CMA area.

Pages residing in CMA areas can usually not get long-term pinned and are
instead migrated away from the CMA area, so long-term pinning is typically
not a concern.  (BUGs in the kernel might still lead to long-term pinning
of such pages if everything goes wrong.)

Pages pinned without FOLL_LONGTERM remain in the CMA and may possibly be
the source or destination of a pending DMA transfer.

Although there is no clear specification how long a page may be pinned
without FOLL_LONGTERM, pinning without the flag shows an intent of the
caller to only use the memory for short-lived DMA transfers, not a
transfer initiated by a device asynchronously at a random time in the
future.

Add a delay of CMA_DMA_TIMEOUT_SEC seconds before starting the kdump
kernel, giving such short-lived DMA transfers time to finish before the
CMA memory is re-used by the kdump kernel.

Set CMA_DMA_TIMEOUT_SEC to 10 seconds - chosen arbitrarily as both a huge
margin for a DMA transfer, yet not increasing the kdump time too
significantly.

Link: https://lkml.kernel.org/r/aEqpgDIBndZ5LXSo@dwarf.suse.cz
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Donald Dutile <ddutile@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Tao Liu <ltao@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:23 -07:00
Jiri Bohac ce1bf19a34 kdump, documentation: describe craskernel CMA reservation 
Describe the new crashkernel ",cma" suffix in Documentation/

Link: https://lkml.kernel.org/r/aEqpQwUy6gqSiUkV@dwarf.suse.cz
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Donald Dutile <ddutile@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Tao Liu <ltao@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:23 -07:00
Jiri Bohac ab475510e0 kdump: implement reserve_crashkernel_cma 
reserve_crashkernel_cma() reserves CMA ranges for the crash kernel.  If
allocating the requested size fails, try to reserve in smaller blocks.

Store the reserved ranges in the crashk_cma_ranges array and the number of
ranges in crashk_cma_cnt.

Link: https://lkml.kernel.org/r/aEqpBwOy_ekm0gw9@dwarf.suse.cz
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Donald Dutile <ddutile@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Tao Liu <ltao@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:23 -07:00
Jiri Bohac 35c18f2933 Add a new optional ",cma" suffix to the crashkernel= command line option 
Patch series "kdump: crashkernel reservation from CMA", v5.

This series implements a way to reserve additional crash kernel memory
using CMA.

Currently, all the memory for the crash kernel is not usable by the 1st
(production) kernel.  It is also unmapped so that it can't be corrupted by
the fault that will eventually trigger the crash.  This makes sense for
the memory actually used by the kexec-loaded crash kernel image and initrd
and the data prepared during the load (vmcoreinfo, ...).  However, the
reserved space needs to be much larger than that to provide enough
run-time memory for the crash kernel and the kdump userspace.  Estimating
the amount of memory to reserve is difficult.  Being too careful makes
kdump likely to end in OOM, being too generous takes even more memory from
the production system.  Also, the reservation only allows reserving a
single contiguous block (or two with the "low" suffix).  I've seen systems
where this fails because the physical memory is fragmented.

By reserving additional crashkernel memory from CMA, the main crashkernel
reservation can be just large enough to fit the kernel and initrd image,
minimizing the memory taken away from the production system.  Most of the
run-time memory for the crash kernel will be memory previously available
to userspace in the production system.  As this memory is no longer
wasted, the reservation can be done with a generous margin, making kdump
more reliable.  Kernel memory that we need to preserve for dumping is
normally not allocated from CMA, unless it is explicitly allocated as
movable.  Currently this is only the case for memory ballooning and zswap.
Such movable memory will be missing from the vmcore.  User data is
typically not dumped by makedumpfile.  When dumping of user data is
intended this new CMA reservation cannot be used.

There are five patches in this series:

The first adds a new ",cma" suffix to the recenly introduced generic
crashkernel parsing code.  parse_crashkernel() takes one more argument to
store the cma reservation size.

The second patch implements reserve_crashkernel_cma() which performs the
reservation.  If the requested size is not available in a single range,
multiple smaller ranges will be reserved.

The third patch updates Documentation/, explicitly mentioning the
potential DMA corruption of the CMA-reserved memory.

The fourth patch adds a short delay before booting the kdump kernel,
allowing pending DMA transfers to finish.

The fifth patch enables the functionality for x86 as a proof of
concept. There are just three things every arch needs to do:
- call reserve_crashkernel_cma()
- include the CMA-reserved ranges in the physical memory map
- exclude the CMA-reserved ranges from the memory available
  through /proc/vmcore by excluding them from the vmcoreinfo
  PT_LOAD ranges.

Adding other architectures is easy and I can do that as soon as this
series is merged.

With this series applied, specifying
	crashkernel=100M craskhernel=1G,cma
on the command line will make a standard crashkernel reservation
of 100M, where kexec will load the kernel and initrd.

An additional 1G will be reserved from CMA, still usable by the production
system.  The crash kernel will have 1.1G memory available.  The 100M can
be reliably predicted based on the size of the kernel and initrd.

The new cma suffix is completely optional. When no
crashkernel=size,cma is specified, everything works as before.


This patch (of 5):

Add a new cma_size parameter to parse_crashkernel().  When not NULL, call
__parse_crashkernel to parse the CMA reservation size from
"crashkernel=size,cma" and store it in cma_size.

Set cma_size to NULL in all calls to parse_crashkernel().

Link: https://lkml.kernel.org/r/aEqnxxfLZMllMC8I@dwarf.suse.cz
Link: https://lkml.kernel.org/r/aEqoQckgoTQNULnh@dwarf.suse.cz
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Donald Dutile <ddutile@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Tao Liu <ltao@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 19:08:22 -07:00
Brian Norris 22c2ed6996 checkpatch: check for missing sentinels in ID arrays 
All of the ID tables based on <linux/mod_devicetable.h> (of_device_id,
pci_device_id, ...) require their arrays to end in an empty sentinel
value.  That's usually spelled with an empty initializer entry (e.g.,
"{}"), but also sometimes with explicit 0 entries, field initializers
(e.g., '.id = ""'), or even a macro entry (like PCMCIA_DEVICE_NULL).

Without a sentinel, device-matching code may read out of bounds.

I've found a number of such bugs in driver reviews, and we even
occasionally commit one to the tree.  See commit 5751eee5c6 ("i2c:
nomadik: Add missing sentinel to match table") for example.

Teach checkpatch to find these ID tables, and complain if it looks like
there wasn't a sentinel value.

Test output:

  $ git format-patch -1 a0d15cc47f --stdout | scripts/checkpatch.pl -
  ERROR: missing sentinel in ID array
  #57: FILE: drivers/i2c/busses/i2c-nomadik.c:1073:
  +static const struct of_device_id nmk_i2c_eyeq_match_table[] = {
   	{
   		.compatible = "XXXXXXXXXXXXXXXXXX",
   		.data = (void *)(NMK_I2C_EYEQ_FLAG_32B_BUS | NMK_I2C_EYEQ_FLAG_IS_EYEQ5),
   	},
   };

  total: 1 errors, 0 warnings, 66 lines checked

  NOTE: For some of the reported defects, checkpatch may be able to
        mechanically convert to the typical style using --fix or --fix-inplace.

  "[PATCH] i2c: nomadik: switch from of_device_is_compatible() to" has style problems, please review.

  NOTE: If any of the errors are false positives, please report
        them to the maintainer, see CHECKPATCH in MAINTAINERS.

When run across the entire tree (scripts/checkpatch.pl -q --types
MISSING_SENTINEL -f ...), false positives exist:

* where macros are used that hide the table from analysis
  (e.g., drivers/gpu/drm/radeon/radeon_drv.c / radeon_PCI_IDS).
  There are fewer than 5 of these.

* where such tables are processed correctly via ARRAY_SIZE() (fewer than
  5 instances). This is by far not the typical usage of *_device_id
  arrays.

* some odd parsing artifacts, where ctx_statement_block() seems to quit
  in the middle of a block due to #if/#else/#endif.

Also, not every "struct *_device_id" is in fact a sentinel-requiring
structure, but even with such types, false positives are very rare.

Link: https://lkml.kernel.org/r/20250702235245.1007351-1-briannorris@chromium.org
Signed-off-by: Brian Norris <briannorris@chromium.org>
Acked-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-09 22:57:57 -07:00
Moon Hee Lee 1f04e0e652 selftests: ptrace: add set_syscall_info to .gitignore 
Add the set_syscall_info test binary to .gitignore to avoid tracking build
artifacts in the ptrace selftests directory.

Link: https://lkml.kernel.org/r/20250623183405.133434-2-moonhee.lee.ca@gmail.com
Signed-off-by: Moon Hee Lee <moonhee.lee.ca@gmail.com>
Cc: "Dmitry V. Levin" <ldv@strace.io>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-09 22:57:57 -07:00
Tetsuo Handa d0118d7d20 ocfs2: update d_splice_alias() return code checking 
When commit d3556babd7 ("ocfs2: fix d_splice_alias() return code
checking") was merged into v3.18-rc3, d_splice_alias() was returning one
of a valid dentry, NULL or an ERR_PTR.

When commit b5ae6b15bd ("merge d_materialise_unique() into
d_splice_alias()") was merged into v3.19-rc1, d_splice_alias() started
returning -ELOOP as one of ERR_PTR values.

Now, when syzkaller mounts a crafted ocfs2 filesystem image that hits
d_splice_alias() == -ELOOP case from ocfs2_lookup(), ocfs2_lookup() fails
to handle -ELOOP case and generic_shutdown_super() hits "VFS: Busy inodes
after unmount" message.

Instead of calling ocfs2_dentry_attach_lock() or ocfs2_dentry_attach_gen()
when d_splice_alias() returned an ERR_PTR value, change ocfs2_lookup() to
bail out immediately.

Also, ocfs2_lookup() needs to call dupt() when ocfs2_dentry_attach_lock()
returned an ERR_PTR value.

Link: https://lkml.kernel.org/r/da5be67d-2a0b-4b93-85d6-42f3b7440135@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+1134d3a5b062e9665a7a@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=1134d3a5b062e9665a7a
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tetsuo Handa <penguin-kernel@i-love-sakura.ne.jp>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-09 22:57:57 -07:00
Su Hui ad0039db42 fs/proc/vmcore: a few cleanups for vmcore_add_device_dump() 
There are two cleanups for vmcore_add_device_dump().  Return -ENOMEM
directly rather than goto the label to simplify the code and use
scoped_guard() to simplify the lock/unlock code.

Link: https://lkml.kernel.org/r/20250626105440.1053139-1-suhui@nfschina.com
Signed-off-by: Su Hui <suhui@nfschina.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Suhui <suhui@nfschina.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-09 22:57:56 -07:00