[ Upstream commit 15def34e26 ]
commit e050e3f0a7 ("perf: Fix broken interrupt rate throttling")
introduces a change in throttling threshold judgment. Before this,
compare hwc->interrupts and max_samples_per_tick, then increase
hwc->interrupts by 1, but this commit reverses order of these two
behaviors, causing the semantics of max_samples_per_tick to change.
In literal sense of "max_samples_per_tick", if hwc->interrupts ==
max_samples_per_tick, it should not be throttled, therefore, the judgment
condition should be changed to "hwc->interrupts > max_samples_per_tick".
In fact, this may cause the hardlockup to fail, The minimum value of
max_samples_per_tick may be 1, in this case, the return value of
__perf_event_account_interrupt function is 1.
As a result, nmi_watchdog gets throttled, which would stop PMU (Use x86
architecture as an example, see x86_pmu_handle_irq).
Fixes: e050e3f0a7 ("perf: Fix broken interrupt rate throttling")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230227023508.102230-1-yangjihong1@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 24d3ae2f37 ]
The same task check in perf_event_set_output has some potential issues
for some usages.
For the current perf code, there is a problem if using of
perf_event_open() to have multiple samples getting into the same mmap’d
memory when they are both attached to the same process.
https://lore.kernel.org/all/92645262-D319-4068-9C44-2409EF44888E@gmail.com/
Because the event->ctx is not ready when the perf_event_set_output() is
invoked in the perf_event_open().
Besides the above issue, before the commit bd27568117 ("perf: Rewrite
core context handling"), perf record can errors out when sampling with
a hardware event and a software event as below.
$ perf record -e cycles,dummy --per-thread ls
failed to mmap with 22 (Invalid argument)
That's because that prior to the commit a hardware event and a software
event are from different task context.
The problem should be a long time issue since commit c3f00c7027
("perk: Separate find_get_context() from event initialization").
The task struct is stored in the event->hw.target for each per-thread
event. It is a more reliable way to determine whether two events are
attached to the same task.
The event->hw.target was also introduced several years ago by the
commit 50f16a8bf9 ("perf: Remove type specific target pointers"). It
can not only be used to fix the issue with the current code, but also
back port to fix the issues with an older kernel.
Note: The event->hw.target was introduced later than commit
c3f00c7027. The patch may cannot be applied between the commit
c3f00c7027 and commit 50f16a8bf9. Anybody that wants to back-port
this at that period may have to find other solutions.
Fixes: c3f00c7027 ("perf: Separate find_get_context() from event initialization")
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
Link: https://lkml.kernel.org/r/20230322202449.512091-1-kan.liang@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit baf1b12a67 ]
Time readers rely on perf_event_context->[time|timestamp|timeoffset] to get
accurate time_enabled and time_running for an event. The difference between
ctx->timestamp and ctx->time is the among of time when the context is not
enabled. __update_context_time(ctx, false) is used to increase timestamp,
but not time. Therefore, it should only be called in ctx_sched_in() when
EVENT_TIME was not enabled.
Fixes: 09f5e7dc7a ("perf: Fix perf_event_read_local() time")
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/r/20230313171608.298734-1-song@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit fd0815f632 upstream.
Events should only be added to a groups rb tree if they have not been
removed from their context by list_del_event(). Since remove_on_exec
made it possible to call list_del_event() on individual events before
they are detached from their group, perf_group_detach() should check each
sibling's attach_state before calling add_event_to_groups() on it.
Fixes: 2e498d0a74 ("perf: Add support for event removal on exec")
Signed-off-by: Budimir Markovic <markovicbudimir@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/ZBFzvQV9tEqoHEtH@gentoo
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e8d7a90c08 ]
In pmu_dev_alloc(), when dev_set_name() failed, it will goto free_dev
and call put_device(pmu->dev) to release it.
However pmu->dev->release is assigned after this, which makes warning
and memleak.
Call dev_set_name() after pmu->dev->release = pmu_dev_release to fix it.
Device '(null)' does not have a release() function...
WARNING: CPU: 2 PID: 441 at drivers/base/core.c:2332 device_release+0x1b9/0x240
...
Call Trace:
<TASK>
kobject_put+0x17f/0x460
put_device+0x20/0x30
pmu_dev_alloc+0x152/0x400
perf_pmu_register+0x96b/0xee0
...
kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
unreferenced object 0xffff888014759000 (size 2048):
comm "modprobe", pid 441, jiffies 4294931444 (age 38.332s)
backtrace:
[<0000000005aed3b4>] kmalloc_trace+0x27/0x110
[<000000006b38f9b8>] pmu_dev_alloc+0x50/0x400
[<00000000735f17be>] perf_pmu_register+0x96b/0xee0
[<00000000e38477f1>] 0xffffffffc0ad8603
[<000000004e162216>] do_one_initcall+0xd0/0x4e0
...
Fixes: abe4340057 ("perf: Sysfs enumeration")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221111103653.91058-1-chenzhongjin@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Pull perf fix from Borislav Petkov:
- Fix a use-after-free case where the perf pending task callback would
see an already freed event
* tag 'perf_urgent_for_v6.1_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Fix perf_pending_task() UaF
Pull networking fixes from Jakub Kicinski:
"Including fixes from bpf, can and wifi.
Current release - new code bugs:
- eth: mlx5e:
- use kvfree() in mlx5e_accel_fs_tcp_create()
- MACsec, fix RX data path 16 RX security channel limit
- MACsec, fix memory leak when MACsec device is deleted
- MACsec, fix update Rx secure channel active field
- MACsec, fix add Rx security association (SA) rule memory leak
Previous releases - regressions:
- wifi: cfg80211: don't allow multi-BSSID in S1G
- stmmac: set MAC's flow control register to reflect current settings
- eth: mlx5:
- E-switch, fix duplicate lag creation
- fix use-after-free when reverting termination table
Previous releases - always broken:
- ipv4: fix route deletion when nexthop info is not specified
- bpf: fix a local storage BPF map bug where the value's spin lock
field can get initialized incorrectly
- tipc: re-fetch skb cb after tipc_msg_validate
- wifi: wilc1000: fix Information Element parsing
- packet: do not set TP_STATUS_CSUM_VALID on CHECKSUM_COMPLETE
- sctp: fix memory leak in sctp_stream_outq_migrate()
- can: can327: fix potential skb leak when netdev is down
- can: add number of missing netdev freeing on error paths
- aquantia: do not purge addresses when setting the number of rings
- wwan: iosm:
- fix incorrect skb length leading to truncated packet
- fix crash in peek throughput test due to skb UAF"
* tag 'net-6.1-rc8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (79 commits)
net: ethernet: renesas: ravb: Fix promiscuous mode after system resumed
MAINTAINERS: Update maintainer list for chelsio drivers
ionic: update MAINTAINERS entry
sctp: fix memory leak in sctp_stream_outq_migrate()
packet: do not set TP_STATUS_CSUM_VALID on CHECKSUM_COMPLETE
net/mlx5: Lag, Fix for loop when checking lag
Revert "net/mlx5e: MACsec, remove replay window size limitation in offload path"
net: marvell: prestera: Fix a NULL vs IS_ERR() check in some functions
net: tun: Fix use-after-free in tun_detach()
net: mdiobus: fix unbalanced node reference count
net: hsr: Fix potential use-after-free
tipc: re-fetch skb cb after tipc_msg_validate
mptcp: fix sleep in atomic at close time
mptcp: don't orphan ssk in mptcp_close()
dsa: lan9303: Correct stat name
ipv4: Fix route deletion when nexthop info is not specified
net: wwan: iosm: fix incorrect skb length
net: wwan: iosm: fix crash in peek throughput test
net: wwan: iosm: fix dma_alloc_coherent incompatible pointer type
net: wwan: iosm: fix kernel test robot reported error
...
Per syzbot it is possible for perf_pending_task() to run after the
event is free()'d. There are two related but distinct cases:
- the task_work was already queued before destroying the event;
- destroying the event itself queues the task_work.
The first cannot be solved using task_work_cancel() since
perf_release() itself might be called from a task_work (____fput),
which means the current->task_works list is already empty and
task_work_cancel() won't be able to find the perf_pending_task()
entry.
The simplest alternative is extending the perf_event lifetime to cover
the task_work.
The second is just silly, queueing a task_work while you know the
event is going away makes no sense and is easily avoided by
re-arranging how the event is marked STATE_DEAD and ensuring it goes
through STATE_OFF on the way down.
Reported-by: syzbot+9228d6098455bb209ec8@syzkaller.appspotmail.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Marco Elver <elver@google.com>
Some PMUs (notably the traditional hardware kind) have boundary issues
with the OS filter. Specifically, it is possible for
perf_event_attr::exclude_kernel=1 events to trigger in-kernel due to
SKID or errata.
This can upset the sigtrap logic some and trigger the WARN.
However, if this invalid sample is the first we must not loose the
SIGTRAP, OTOH if it is the second, it must not override the
pending_addr with a (possibly) invalid one.
Fixes: ca6c21327c ("perf: Fix missing SIGTRAPs")
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Marco Elver <elver@google.com>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Link: https://lkml.kernel.org/r/Y3hDYiXwRnJr8RYG@xpf.sh.intel.com
Since commit bfea9a8574 ("bpf: Add name to struct bpf_ksym"), when
reporting subprog ksymbol to perf, prog name instead of subprog name is
used. The backtrace of bpf program with subprogs will be incorrect as
shown below:
ffffffffc02deace bpf_prog_e44a3057dcb151f8_overwrite+0x66
ffffffffc02de9f7 bpf_prog_e44a3057dcb151f8_overwrite+0x9f
ffffffffa71d8d4e trace_call_bpf+0xce
ffffffffa71c2938 perf_call_bpf_enter.isra.0+0x48
overwrite is the entry program and it invokes the overwrite_htab subprog
through bpf_loop, but in above backtrace, overwrite program just jumps
inside itself.
Fixing it by using subprog name when reporting subprog ksymbol. After
the fix, the output of perf script will be correct as shown below:
ffffffffc031aad2 bpf_prog_37c0bec7d7c764a4_overwrite_htab+0x66
ffffffffc031a9e7 bpf_prog_c7eb827ef4f23e71_overwrite+0x9f
ffffffffa3dd8d4e trace_call_bpf+0xce
ffffffffa3dc2938 perf_call_bpf_enter.isra.0+0x48
Fixes: bfea9a8574 ("bpf: Add name to struct bpf_ksym")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20221114095733.158588-1-houtao@huaweicloud.com
To catch missing SIGTRAP we employ a WARN in __perf_event_overflow(),
which fires if pending_sigtrap was already set: returning to user space
without consuming pending_sigtrap, and then having the event fire again
would re-enter the kernel and trigger the WARN.
This, however, seemed to miss the case where some events not associated
with progress in the user space task can fire and the interrupt handler
runs before the IRQ work meant to consume pending_sigtrap (and generate
the SIGTRAP).
syzbot gifted us this stack trace:
| WARNING: CPU: 0 PID: 3607 at kernel/events/core.c:9313 __perf_event_overflow
| Modules linked in:
| CPU: 0 PID: 3607 Comm: syz-executor100 Not tainted 6.1.0-rc2-syzkaller-00073-g88619e77b33d #0
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
| RIP: 0010:__perf_event_overflow+0x498/0x540 kernel/events/core.c:9313
| <...>
| Call Trace:
| <TASK>
| perf_swevent_hrtimer+0x34f/0x3c0 kernel/events/core.c:10729
| __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
| __hrtimer_run_queues+0x1c6/0xfb0 kernel/time/hrtimer.c:1749
| hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811
| local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1096 [inline]
| __sysvec_apic_timer_interrupt+0x17c/0x640 arch/x86/kernel/apic/apic.c:1113
| sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1107
| asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
| <...>
| </TASK>
In this case, syzbot produced a program with event type
PERF_TYPE_SOFTWARE and config PERF_COUNT_SW_CPU_CLOCK. The hrtimer
manages to fire again before the IRQ work got a chance to run, all while
never having returned to user space.
Improve the WARN to check for real progress in user space: approximate
this by storing a 32-bit hash of the current IP into pending_sigtrap,
and if an event fires while pending_sigtrap still matches the previous
IP, we assume no progress (false negatives are possible given we could
return to user space and trigger again on the same IP).
Fixes: ca6c21327c ("perf: Fix missing SIGTRAPs")
Reported-by: syzbot+b8ded3e2e2c6adde4990@syzkaller.appspotmail.com
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221031093513.3032814-1-elver@google.com
Since commit 838d9bb62d ("perf: Use sample_flags for raw_data")
raw data is not being output on tracepoints due to the PERF_SAMPLE_RAW
field not being set. Fix this by setting it for tracepoint events.
This fixes the following test failure:
perf test "sched_switch" -vvv
35: Track with sched_switch
--- start ---
test child forked, pid 1828
...
Using CPUID 0x00000000410fd400
sched_switch: cpu: 2 prev_tid -14687 next_tid 0
sched_switch: cpu: 2 prev_tid -14687 next_tid 0
Missing sched_switch events
4613 events recorded
test child finished with -1
---- end ----
Track with sched_switch: FAILED!
Fixes: 838d9bb62d ("perf: Use sample_flags for raw_data")
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: SeongJae Park <sj@kernel.org>
Tested-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20221012143857.48198-1-james.clark@arm.com
Marco reported:
Due to the implementation of how SIGTRAP are delivered if
perf_event_attr::sigtrap is set, we've noticed 3 issues:
1. Missing SIGTRAP due to a race with event_sched_out() (more
details below).
2. Hardware PMU events being disabled due to returning 1 from
perf_event_overflow(). The only way to re-enable the event is
for user space to first "properly" disable the event and then
re-enable it.
3. The inability to automatically disable an event after a
specified number of overflows via PERF_EVENT_IOC_REFRESH.
The worst of the 3 issues is problem (1), which occurs when a
pending_disable is "consumed" by a racing event_sched_out(), observed
as follows:
CPU0 | CPU1
--------------------------------+---------------------------
__perf_event_overflow() |
perf_event_disable_inatomic() |
pending_disable = CPU0 | ...
| _perf_event_enable()
| event_function_call()
| task_function_call()
| /* sends IPI to CPU0 */
<IPI> | ...
__perf_event_enable() +---------------------------
ctx_resched()
task_ctx_sched_out()
ctx_sched_out()
group_sched_out()
event_sched_out()
pending_disable = -1
</IPI>
<IRQ-work>
perf_pending_event()
perf_pending_event_disable()
/* Fails to send SIGTRAP because no pending_disable! */
</IRQ-work>
In the above case, not only is that particular SIGTRAP missed, but also
all future SIGTRAPs because 'event_limit' is not reset back to 1.
To fix, rework pending delivery of SIGTRAP via IRQ-work by introduction
of a separate 'pending_sigtrap', no longer using 'event_limit' and
'pending_disable' for its delivery.
Additionally; and different to Marco's proposed patch:
- recognise that pending_disable effectively duplicates oncpu for
the case where it is set. As such, change the irq_work handler to
use ->oncpu to target the event and use pending_* as boolean toggles.
- observe that SIGTRAP targets the ctx->task, so the context switch
optimization that carries contexts between tasks is invalid. If
the irq_work were delayed enough to hit after a context switch the
SIGTRAP would be delivered to the wrong task.
- observe that if the event gets scheduled out
(rotation/migration/context-switch/...) the irq-work would be
insufficient to deliver the SIGTRAP when the event gets scheduled
back in (the irq-work might still be pending on the old CPU).
Therefore have event_sched_out() convert the pending sigtrap into a
task_work which will deliver the signal at return_to_user.
Fixes: 97ba62b278 ("perf: Add support for SIGTRAP on perf events")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Debugged-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: Marco Elver <elver@google.com>
Debugged-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Marco Elver <elver@google.com>
Tested-by: Marco Elver <elver@google.com>
Pull MM updates from Andrew Morton:
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any
negative reports (or any positive ones, come to that).
- Also the Maple Tree from Liam Howlett. An overlapping range-based
tree for vmas. It it apparently slightly more efficient in its own
right, but is mainly targeted at enabling work to reduce mmap_lock
contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
at [1]. This has yet to be addressed due to Liam's unfortunately
timed vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down
to the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
support file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging
activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]
* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
hugetlb: allocate vma lock for all sharable vmas
hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb: fix vma lock handling during split vma and range unmapping
mglru: mm/vmscan.c: fix imprecise comments
mm/mglru: don't sync disk for each aging cycle
mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
mm: memcontrol: use do_memsw_account() in a few more places
mm: memcontrol: deprecate swapaccounting=0 mode
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
mm/secretmem: remove reduntant return value
mm/hugetlb: add available_huge_pages() func
mm: remove unused inline functions from include/linux/mm_inline.h
selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
selftests/vm: add thp collapse shmem testing
selftests/vm: add thp collapse file and tmpfs testing
selftests/vm: modularize thp collapse memory operations
selftests/vm: dedup THP helpers
mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
mm/madvise: add file and shmem support to MADV_COLLAPSE
...
Pull perf events updates from Ingo Molnar:
"PMU driver updates:
- Add AMD Last Branch Record Extension Version 2 (LbrExtV2) feature
support for Zen 4 processors.
- Extend the perf ABI to provide branch speculation information, if
available, and use this on CPUs that have it (eg. LbrExtV2).
- Improve Intel PEBS TSC timestamp handling & integration.
- Add Intel Raptor Lake S CPU support.
- Add 'perf mem' and 'perf c2c' memory profiling support on AMD CPUs
by utilizing IBS tagged load/store samples.
- Clean up & optimize various x86 PMU details.
HW breakpoints:
- Big rework to optimize the code for systems with hundreds of CPUs
and thousands of breakpoints:
- Replace the nr_bp_mutex global mutex with the bp_cpuinfo_sem
per-CPU rwsem that is read-locked during most of the key
operations.
- Improve the O(#cpus * #tasks) logic in toggle_bp_slot() and
fetch_bp_busy_slots().
- Apply micro-optimizations & cleanups.
- Misc cleanups & enhancements"
* tag 'perf-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits)
perf/hw_breakpoint: Annotate tsk->perf_event_mutex vs ctx->mutex
perf: Fix pmu_filter_match()
perf: Fix lockdep_assert_event_ctx()
perf/x86/amd/lbr: Adjust LBR regardless of filtering
perf/x86/utils: Fix uninitialized var in get_branch_type()
perf/uapi: Define PERF_MEM_SNOOPX_PEER in kernel header file
perf/x86/amd: Support PERF_SAMPLE_PHY_ADDR
perf/x86/amd: Support PERF_SAMPLE_ADDR
perf/x86/amd: Support PERF_SAMPLE_{WEIGHT|WEIGHT_STRUCT}
perf/x86/amd: Support PERF_SAMPLE_DATA_SRC
perf/x86/amd: Add IBS OP_DATA2 DataSrc bit definitions
perf/mem: Introduce PERF_MEM_LVLNUM_{EXTN_MEM|IO}
perf/x86/uncore: Add new Raptor Lake S support
perf/x86/cstate: Add new Raptor Lake S support
perf/x86/msr: Add new Raptor Lake S support
perf/x86: Add new Raptor Lake S support
bpf: Check flags for branch stack in bpf_read_branch_records helper
perf, hw_breakpoint: Fix use-after-free if perf_event_open() fails
perf: Use sample_flags for raw_data
perf: Use sample_flags for addr
...
Local testing revealed that we can trigger a use-after-free during
rhashtable lookup as follows:
| BUG: KASAN: use-after-free in memcmp lib/string.c:757
| Read of size 8 at addr ffff888107544dc0 by task perf-rhltable-n/1293
|
| CPU: 0 PID: 1293 Comm: perf-rhltable-n Not tainted 6.0.0-rc3-00014-g85260862789c #46
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014
| Call Trace:
| <TASK>
| memcmp lib/string.c:757
| rhashtable_compare include/linux/rhashtable.h:577 [inline]
| __rhashtable_lookup include/linux/rhashtable.h:602 [inline]
| rhltable_lookup include/linux/rhashtable.h:688 [inline]
| task_bp_pinned kernel/events/hw_breakpoint.c:324
| toggle_bp_slot kernel/events/hw_breakpoint.c:462
| __release_bp_slot kernel/events/hw_breakpoint.c:631 [inline]
| release_bp_slot kernel/events/hw_breakpoint.c:639
| register_perf_hw_breakpoint kernel/events/hw_breakpoint.c:742
| hw_breakpoint_event_init kernel/events/hw_breakpoint.c:976
| perf_try_init_event kernel/events/core.c:11261
| perf_init_event kernel/events/core.c:11325 [inline]
| perf_event_alloc kernel/events/core.c:11619
| __do_sys_perf_event_open kernel/events/core.c:12157
| do_syscall_x64 arch/x86/entry/common.c:50 [inline]
| do_syscall_64 arch/x86/entry/common.c:80
| entry_SYSCALL_64_after_hwframe
| </TASK>
|
| Allocated by task 1292:
| perf_event_alloc kernel/events/core.c:11505
| __do_sys_perf_event_open kernel/events/core.c:12157
| do_syscall_x64 arch/x86/entry/common.c:50 [inline]
| do_syscall_64 arch/x86/entry/common.c:80
| entry_SYSCALL_64_after_hwframe
|
| Freed by task 1292:
| perf_event_alloc kernel/events/core.c:11716
| __do_sys_perf_event_open kernel/events/core.c:12157
| do_syscall_x64 arch/x86/entry/common.c:50 [inline]
| do_syscall_64 arch/x86/entry/common.c:80
| entry_SYSCALL_64_after_hwframe
|
| The buggy address belongs to the object at ffff888107544c00
| which belongs to the cache perf_event of size 1352
| The buggy address is located 448 bytes inside of
| 1352-byte region [ffff888107544c00, ffff888107545148)
This happens because the first perf_event_open() managed to reserve a HW
breakpoint slot, however, later fails for other reasons and returns. The
second perf_event_open() runs concurrently, and during rhltable_lookup()
looks up an entry which is being freed: since rhltable_lookup() may run
concurrently (under the RCU read lock) with rhltable_remove(), we may
end up with a stale entry, for which memory may also have already been
freed when being accessed.
To fix, only free the failed perf_event after an RCU grace period. This
allows subsystems that store references to an event to always access it
concurrently under the RCU read lock, even if initialization will fail.
Given failure is unlikely and a slow-path, turning the immediate free
into a call_rcu()-wrapped free does not affect performance elsewhere.
Fixes: 0370dc314d ("perf/hw_breakpoint: Optimize list of per-task breakpoints")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220927172025.1636995-1-elver@google.com
Use the new sample_flags to indicate whether the raw data field is
filled by the PMU driver. Although it could check with the NULL,
follow the same rule with other fields.
Remove the raw field from the perf_sample_data_init() to minimize
the number of cache lines touched.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220921220032.2858517-2-namhyung@kernel.org
Coccinelle reports a warning:
WARNING: use scnprintf or sprintf
This LWN article explains the rationale for this change:
https: //lwn.net/Articles/69419/
Ie. snprintf() returns what *would* be the resulting length,
while scnprintf() returns the actual length.
Adding to that, there has also been some slow migration from snprintf to scnprintf,
here's the shift in usage in the past 3.5 years, in all fs/ files:
v5.0 v6.0-rc6
--------------------------------------
snprintf() uses: 63 213
scnprintf() uses: 374 186
No intended change in behavior.
[ mingo: Improved the changelog & reviewed the usage sites. ]
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If the perf_event has PERF_SAMPLE_CALLCHAIN, BPF can use it for stack trace.
The problematic cases like PEBS and IBS already handled in the PMU driver and
they filled the callchain info in the sample data. For others, we can call
perf_callchain() before the BPF handler.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908214104.3851807-2-namhyung@kernel.org
While auditing 6b959ba22d ("perf/core: Fix reentry problem in
perf_output_read_group()") a few spots were found that wanted
assertions.
Notable for_each_sibling_event() relies on exclusion from
modification. This would normally be holding either ctx->lock or
ctx->mutex, however due to how things are constructed disabling IRQs
is a valid and sufficient substitute for ctx->lock.
Another possible site to add assertions would be the various
pmu::{add,del,read,..}() methods, but that's not trivially expressable
in C -- the best option is wrappers, but those are easy enough to
forget.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Besides the branch type filtering requests, 'event.attr.branch_sample_type'
also contains various flags indicating which additional information should
be captured, along with the base branch record. These flags help configure
the underlying hardware, and capture the branch records appropriately when
required e.g after PMU interrupt. But first, this moves an existing helper
perf_sample_save_hw_index() into the header before adding some more helpers
for other branch sample filter flags.
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220906084414.396220-1-anshuman.khandual@arm.com
On some platforms, some data e.g., timestamps, can be retrieved from
the PMU driver. Usually, the data from the PMU driver is more accurate.
The current perf kernel should output the PMU-filled sample data if
it's available.
To check the availability of the PMU-filled sample data, the current
perf kernel initializes the related fields in the
perf_sample_data_init(). When outputting a sample, the perf checks
whether the field is updated by the PMU driver. If yes, the updated
value will be output. If not, the perf uses an SW way to calculate the
value or just outputs the initialized value if an SW way is unavailable
either.
With more and more data being provided by the PMU driver, more fields
has to be initialized in the perf_sample_data_init(). That will
increase the number of cache lines touched in perf_sample_data_init()
and be harmful to the performance.
Add new "sample_flags" to indicate the PMU-filled sample data. The PMU
driver should set the corresponding PERF_SAMPLE_ flag when the field is
updated. The initialization of the corresponding field is not required
anymore. The following patches will make use of it and remove the
corresponding fields from the perf_sample_data_init(), which will
further minimize the number of cache lines touched.
Only clear the sample flags that have already been done by the PMU
driver in the perf_prepare_sample() for the PERF_RECORD_SAMPLE. For the
other PERF_RECORD_ event type, the sample data is not available.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220901130959.1285717-2-kan.liang@linux.intel.com
perf_output_read_group may respond to IPI request of other cores and invoke
__perf_install_in_context function. As a result, hwc configuration is modified.
causing inconsistency and unexpected consequences.
Interrupts are not disabled when perf_output_read_group reads PMU counter.
In this case, IPI request may be received from other cores.
As a result, PMU configuration is modified and an error occurs when
reading PMU counter:
CPU0 CPU1
__se_sys_perf_event_open
perf_install_in_context
perf_output_read_group smp_call_function_single
for_each_sibling_event(sub, leader) { generic_exec_single
if ((sub != event) && remote_function
(sub->state == PERF_EVENT_STATE_ACTIVE)) |
<enter IPI handler: __perf_install_in_context> <----RAISE IPI-----+
__perf_install_in_context
ctx_resched
event_sched_out
armpmu_del
...
hwc->idx = -1; // event->hwc.idx is set to -1
...
<exit IPI>
sub->pmu->read(sub);
armpmu_read
armv8pmu_read_counter
armv8pmu_read_hw_counter
int idx = event->hw.idx; // idx = -1
u64 val = armv8pmu_read_evcntr(idx);
u32 counter = ARMV8_IDX_TO_COUNTER(idx); // invalid counter = 30
read_pmevcntrn(counter) // undefined instruction
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220902082918.179248-1-yangjihong1@huawei.com
Pull perf fixes from Ingo Molnar:
"Misc fixes to kprobes and the faddr2line script, plus a cleanup"
* tag 'perf-urgent-2022-08-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Fix ';;' typo
scripts/faddr2line: Add CONFIG_DEBUG_INFO check
scripts/faddr2line: Fix vmlinux detection on arm64
x86/kprobes: Update kcb status flag after singlestepping
kprobes: Forbid probing on trampoline and BPF code areas
Pull networking changes from Paolo Abeni:
"Core:
- Refactor the forward memory allocation to better cope with memory
pressure with many open sockets, moving from a per socket cache to
a per-CPU one
- Replace rwlocks with RCU for better fairness in ping, raw sockets
and IP multicast router.
- Network-side support for IO uring zero-copy send.
- A few skb drop reason improvements, including codegen the source
file with string mapping instead of using macro magic.
- Rename reference tracking helpers to a more consistent netdev_*
schema.
- Adapt u64_stats_t type to address load/store tearing issues.
- Refine debug helper usage to reduce the log noise caused by bots.
BPF:
- Improve socket map performance, avoiding skb cloning on read
operation.
- Add support for 64 bits enum, to match types exposed by kernel.
- Introduce support for sleepable uprobes program.
- Introduce support for enum textual representation in libbpf.
- New helpers to implement synproxy with eBPF/XDP.
- Improve loop performances, inlining indirect calls when possible.
- Removed all the deprecated libbpf APIs.
- Implement new eBPF-based LSM flavor.
- Add type match support, which allow accurate queries to the eBPF
used types.
- A few TCP congetsion control framework usability improvements.
- Add new infrastructure to manipulate CT entries via eBPF programs.
- Allow for livepatch (KLP) and BPF trampolines to attach to the same
kernel function.
Protocols:
- Introduce per network namespace lookup tables for unix sockets,
increasing scalability and reducing contention.
- Preparation work for Wi-Fi 7 Multi-Link Operation (MLO) support.
- Add support to forciby close TIME_WAIT TCP sockets via user-space
tools.
- Significant performance improvement for the TLS 1.3 receive path,
both for zero-copy and not-zero-copy.
- Support for changing the initial MTPCP subflow priority/backup
status
- Introduce virtually contingus buffers for sockets over RDMA, to
cope better with memory pressure.
- Extend CAN ethtool support with timestamping capabilities
- Refactor CAN build infrastructure to allow building only the needed
features.
Driver API:
- Remove devlink mutex to allow parallel commands on multiple links.
- Add support for pause stats in distributed switch.
- Implement devlink helpers to query and flash line cards.
- New helper for phy mode to register conversion.
New hardware / drivers:
- Ethernet DSA driver for the rockchip mt7531 on BPI-R2 Pro.
- Ethernet DSA driver for the Renesas RZ/N1 A5PSW switch.
- Ethernet DSA driver for the Microchip LAN937x switch.
- Ethernet PHY driver for the Aquantia AQR113C EPHY.
- CAN driver for the OBD-II ELM327 interface.
- CAN driver for RZ/N1 SJA1000 CAN controller.
- Bluetooth: Infineon CYW55572 Wi-Fi plus Bluetooth combo device.
Drivers:
- Intel Ethernet NICs:
- i40e: add support for vlan pruning
- i40e: add support for XDP framented packets
- ice: improved vlan offload support
- ice: add support for PPPoE offload
- Mellanox Ethernet (mlx5)
- refactor packet steering offload for performance and scalability
- extend support for TC offload
- refactor devlink code to clean-up the locking schema
- support stacked vlans for bridge offloads
- use TLS objects pool to improve connection rate
- Netronome Ethernet NICs (nfp):
- extend support for IPv6 fields mangling offload
- add support for vepa mode in HW bridge
- better support for virtio data path acceleration (VDPA)
- enable TSO by default
- Microsoft vNIC driver (mana)
- add support for XDP redirect
- Others Ethernet drivers:
- bonding: add per-port priority support
- microchip lan743x: extend phy support
- Fungible funeth: support UDP segmentation offload and XDP xmit
- Solarflare EF100: add support for virtual function representors
- MediaTek SoC: add XDP support
- Mellanox Ethernet/IB switch (mlxsw):
- dropped support for unreleased H/W (XM router).
- improved stats accuracy
- unified bridge model coversion improving scalability (parts 1-6)
- support for PTP in Spectrum-2 asics
- Broadcom PHYs
- add PTP support for BCM54210E
- add support for the BCM53128 internal PHY
- Marvell Ethernet switches (prestera):
- implement support for multicast forwarding offload
- Embedded Ethernet switches:
- refactor OcteonTx MAC filter for better scalability
- improve TC H/W offload for the Felix driver
- refactor the Microchip ksz8 and ksz9477 drivers to share the
probe code (parts 1, 2), add support for phylink mac
configuration
- Other WiFi:
- Microchip wilc1000: diable WEP support and enable WPA3
- Atheros ath10k: encapsulation offload support
Old code removal:
- Neterion vxge ethernet driver: this is untouched since more than 10 years"
* tag 'net-next-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1890 commits)
doc: sfp-phylink: Fix a broken reference
wireguard: selftests: support UML
wireguard: allowedips: don't corrupt stack when detecting overflow
wireguard: selftests: update config fragments
wireguard: ratelimiter: use hrtimer in selftest
net/mlx5e: xsk: Discard unaligned XSK frames on striding RQ
net: usb: ax88179_178a: Bind only to vendor-specific interface
selftests: net: fix IOAM test skip return code
net: usb: make USB_RTL8153_ECM non user configurable
net: marvell: prestera: remove reduntant code
octeontx2-pf: Reduce minimum mtu size to 60
net: devlink: Fix missing mutex_unlock() call
net/tls: Remove redundant workqueue flush before destroy
net: txgbe: Fix an error handling path in txgbe_probe()
net: dsa: Fix spelling mistakes and cleanup code
Documentation: devlink: add add devlink-selftests to the table of contents
dccp: put dccp_qpolicy_full() and dccp_qpolicy_push() in the same lock
net: ionic: fix error check for vlan flags in ionic_set_nic_features()
net: ice: fix error NETIF_F_HW_VLAN_CTAG_FILTER check in ice_vsi_sync_fltr()
nfp: flower: add support for tunnel offload without key ID
...
Pull perf events updates from Ingo Molnar:
- Fix Intel Alder Lake PEBS memory access latency & data source
profiling info bugs.
- Use Intel large-PEBS hardware feature in more circumstances, to
reduce PMI overhead & reduce sampling data.
- Extend the lost-sample profiling output with the PERF_FORMAT_LOST ABI
variant, which tells tooling the exact number of samples lost.
- Add new IBS register bits definitions.
- AMD uncore events: Add PerfMonV2 DF (Data Fabric) enhancements.
* tag 'perf-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/ibs: Add new IBS register bits into header
perf/x86/intel: Fix PEBS data source encoding for ADL
perf/x86/intel: Fix PEBS memory access info encoding for ADL
perf/core: Add a new read format to get a number of lost samples
perf/x86/amd/uncore: Add PerfMonV2 RDPMC assignments
perf/x86/amd/uncore: Add PerfMonV2 DF event format
perf/x86/amd/uncore: Detect available DF counters
perf/x86/amd/uncore: Use attr_update for format attributes
perf/x86/amd/uncore: Use dynamic events array
x86/events/intel/ds: Enable large PEBS for PERF_SAMPLE_WEIGHT_TYPE
Yang Jihing reported a race between perf_event_set_output() and
perf_mmap_close():
CPU1 CPU2
perf_mmap_close(e2)
if (atomic_dec_and_test(&e2->rb->mmap_count)) // 1 - > 0
detach_rest = true
ioctl(e1, IOC_SET_OUTPUT, e2)
perf_event_set_output(e1, e2)
...
list_for_each_entry_rcu(e, &e2->rb->event_list, rb_entry)
ring_buffer_attach(e, NULL);
// e1 isn't yet added and
// therefore not detached
ring_buffer_attach(e1, e2->rb)
list_add_rcu(&e1->rb_entry,
&e2->rb->event_list)
After this; e1 is attached to an unmapped rb and a subsequent
perf_mmap() will loop forever more:
again:
mutex_lock(&e->mmap_mutex);
if (event->rb) {
...
if (!atomic_inc_not_zero(&e->rb->mmap_count)) {
...
mutex_unlock(&e->mmap_mutex);
goto again;
}
}
The loop in perf_mmap_close() holds e2->mmap_mutex, while the attach
in perf_event_set_output() holds e1->mmap_mutex. As such there is no
serialization to avoid this race.
Change perf_event_set_output() to take both e1->mmap_mutex and
e2->mmap_mutex to alleviate that problem. Additionally, have the loop
in perf_mmap() detach the rb directly, this avoids having to wait for
the concurrent perf_mmap_close() to get around to doing it to make
progress.
Fixes: 9bb5d40cd9 ("perf: Fix mmap() accounting hole")
Reported-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Yang Jihong <yangjihong1@huawei.com>
Link: https://lkml.kernel.org/r/YsQ3jm2GR38SW7uD@worktop.programming.kicks-ass.net
Sometimes we want to know an accurate number of samples even if it's
lost. Currenlty PERF_RECORD_LOST is generated for a ring-buffer which
might be shared with other events. So it's hard to know per-event
lost count.
Add event->lost_samples field and PERF_FORMAT_LOST to retrieve it from
userspace.
Original-patch-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220616180623.1358843-1-namhyung@kernel.org
Daniel Borkmann says:
====================
pull-request: bpf-next 2022-06-17
We've added 72 non-merge commits during the last 15 day(s) which contain
a total of 92 files changed, 4582 insertions(+), 834 deletions(-).
The main changes are:
1) Add 64 bit enum value support to BTF, from Yonghong Song.
2) Implement support for sleepable BPF uprobe programs, from Delyan Kratunov.
3) Add new BPF helpers to issue and check TCP SYN cookies without binding to a
socket especially useful in synproxy scenarios, from Maxim Mikityanskiy.
4) Fix libbpf's internal USDT address translation logic for shared libraries as
well as uprobe's symbol file offset calculation, from Andrii Nakryiko.
5) Extend libbpf to provide an API for textual representation of the various
map/prog/attach/link types and use it in bpftool, from Daniel Müller.
6) Provide BTF line info for RV64 and RV32 JITs, and fix a put_user bug in the
core seen in 32 bit when storing BPF function addresses, from Pu Lehui.
7) Fix libbpf's BTF pointer size guessing by adding a list of various aliases
for 'long' types, from Douglas Raillard.
8) Fix bpftool to readd setting rlimit since probing for memcg-based accounting
has been unreliable and caused a regression on COS, from Quentin Monnet.
9) Fix UAF in BPF cgroup's effective program computation triggered upon BPF link
detachment, from Tadeusz Struk.
10) Fix bpftool build bootstrapping during cross compilation which was pointing
to the wrong AR process, from Shahab Vahedi.
11) Fix logic bug in libbpf's is_pow_of_2 implementation, from Yuze Chi.
12) BPF hash map optimization to avoid grabbing spinlocks of all CPUs when there
is no free element. Also add a benchmark as reproducer, from Feng Zhou.
13) Fix bpftool's codegen to bail out when there's no BTF, from Michael Mullin.
14) Various minor cleanup and improvements all over the place.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (72 commits)
bpf: Fix bpf_skc_lookup comment wrt. return type
bpf: Fix non-static bpf_func_proto struct definitions
selftests/bpf: Don't force lld on non-x86 architectures
selftests/bpf: Add selftests for raw syncookie helpers in TC mode
bpf: Allow the new syncookie helpers to work with SKBs
selftests/bpf: Add selftests for raw syncookie helpers
bpf: Add helpers to issue and check SYN cookies in XDP
bpf: Allow helpers to accept pointers with a fixed size
bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie
selftests/bpf: add tests for sleepable (uk)probes
libbpf: add support for sleepable uprobe programs
bpf: allow sleepable uprobe programs to attach
bpf: implement sleepable uprobes by chaining gps
bpf: move bpf_prog to bpf.h
libbpf: Fix internal USDT address translation logic for shared libraries
samples/bpf: Check detach prog exist or not in xdp_fwd
selftests/bpf: Avoid skipping certain subtests
selftests/bpf: Fix test_varlen verification failure with latest llvm
bpftool: Do not check return value from libbpf_set_strict_mode()
Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"
...
====================
Link: https://lore.kernel.org/r/20220617220836.7373-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
uprobe and kprobe programs have the same program type, KPROBE, which is
currently not allowed to load sleepable programs.
To avoid adding a new UPROBE type, instead allow sleepable KPROBE
programs to load and defer the is-it-actually-a-uprobe-program check
to attachment time, where there's already validation of the
corresponding perf_event.
A corollary of this patch is that you can now load a sleepable kprobe
program but cannot attach it.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Delyan Kratunov <delyank@fb.com>
Link: https://lore.kernel.org/r/fcd44a7cd204f372f6bb03ef794e829adeaef299.1655248076.git.delyank@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull perf events updates from Ingo Molnar:
"Platform PMU changes:
- x86/intel:
- Add new Intel Alder Lake and Raptor Lake support
- x86/amd:
- AMD Zen4 IBS extensions support
- Add AMD PerfMonV2 support
- Add AMD Fam19h Branch Sampling support
Generic changes:
- signal: Deliver SIGTRAP on perf event asynchronously if blocked
Perf instrumentation can be driven via SIGTRAP, but this causes a
problem when SIGTRAP is blocked by a task & terminate the task.
Allow user-space to request these signals asynchronously (after
they get unblocked) & also give the information to the signal
handler when this happens:
"To give user space the ability to clearly distinguish
synchronous from asynchronous signals, introduce
siginfo_t::si_perf_flags and TRAP_PERF_FLAG_ASYNC (opted for
flags in case more binary information is required in future).
The resolution to the problem is then to (a) no longer force the
signal (avoiding the terminations), but (b) tell user space via
si_perf_flags if the signal was synchronous or not, so that such
signals can be handled differently (e.g. let user space decide
to ignore or consider the data imprecise). "
- Unify/standardize the /sys/devices/cpu/events/* output format.
- Misc fixes & cleanups"
* tag 'perf-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
perf/x86/amd/core: Fix reloading events for SVM
perf/x86/amd: Run AMD BRS code only on supported hw
perf/x86/amd: Fix AMD BRS period adjustment
perf/x86/amd: Remove unused variable 'hwc'
perf/ibs: Fix comment
perf/amd/ibs: Advertise zen4_ibs_extensions as pmu capability attribute
perf/amd/ibs: Add support for L3 miss filtering
perf/amd/ibs: Use ->is_visible callback for dynamic attributes
perf/amd/ibs: Cascade pmu init functions' return value
perf/x86/uncore: Add new Alder Lake and Raptor Lake support
perf/x86/uncore: Clean up uncore_pci_ids[]
perf/x86/cstate: Add new Alder Lake and Raptor Lake support
perf/x86/msr: Add new Alder Lake and Raptor Lake support
perf/x86: Add new Alder Lake and Raptor Lake support
perf/amd/ibs: Use interrupt regs ip for stack unwinding
perf/x86/amd/core: Add PerfMonV2 overflow handling
perf/x86/amd/core: Add PerfMonV2 counter control
perf/x86/amd/core: Detect available counters
perf/x86/amd/core: Detect PerfMonV2 support
x86/msr: Add PerfCntrGlobal* registers
...
Norbert reported that it's possible to race sys_perf_event_open() such
that the looser ends up in another context from the group leader,
triggering many WARNs.
The move_group case checks for races against itself, but the
!move_group case doesn't, seemingly relying on the previous
group_leader->ctx == ctx check. However, that check is racy due to not
holding any locks at that time.
Therefore, re-check the result after acquiring locks and bailing
if they no longer match.
Additionally, clarify the not_move_group case from the
move_group-vs-move_group race.
Fixes: f63a8daa58 ("perf: Fix event->ctx locking")
Reported-by: Norbert Slusarek <nslusarek@gmx.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With SIGTRAP on perf events, we have encountered termination of
processes due to user space attempting to block delivery of SIGTRAP.
Consider this case:
<set up SIGTRAP on a perf event>
...
sigset_t s;
sigemptyset(&s);
sigaddset(&s, SIGTRAP | <and others>);
sigprocmask(SIG_BLOCK, &s, ...);
...
<perf event triggers>
When the perf event triggers, while SIGTRAP is blocked, force_sig_perf()
will force the signal, but revert back to the default handler, thus
terminating the task.
This makes sense for error conditions, but not so much for explicitly
requested monitoring. However, the expectation is still that signals
generated by perf events are synchronous, which will no longer be the
case if the signal is blocked and delivered later.
To give user space the ability to clearly distinguish synchronous from
asynchronous signals, introduce siginfo_t::si_perf_flags and
TRAP_PERF_FLAG_ASYNC (opted for flags in case more binary information is
required in future).
The resolution to the problem is then to (a) no longer force the signal
(avoiding the terminations), but (b) tell user space via si_perf_flags
if the signal was synchronous or not, so that such signals can be
handled differently (e.g. let user space decide to ignore or consider
the data imprecise).
The alternative of making the kernel ignore SIGTRAP on perf events if
the signal is blocked may work for some usecases, but likely causes
issues in others that then have to revert back to interception of
sigprocmask() (which we want to avoid). [ A concrete example: when using
breakpoint perf events to track data-flow, in a region of code where
signals are blocked, data-flow can no longer be tracked accurately.
When a relevant asynchronous signal is received after unblocking the
signal, the data-flow tracking logic needs to know its state is
imprecise. ]
Fixes: 97ba62b278 ("perf: Add support for SIGTRAP on perf events")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://lore.kernel.org/r/20220404111204.935357-1-elver@google.com
This problem can be reproduced with CONFIG_PERF_USE_VMALLOC enabled on
both x86_64 and aarch64 arch when using sysdig -B(using ebpf)[1].
sysdig -B works fine after rebuilding the kernel with
CONFIG_PERF_USE_VMALLOC disabled.
I tracked it down to the if condition event->rb->nr_pages != nr_pages
in perf_mmap is true when CONFIG_PERF_USE_VMALLOC is enabled where
event->rb->nr_pages = 1 and nr_pages = 2048 resulting perf_mmap to
return -EINVAL. This is because when CONFIG_PERF_USE_VMALLOC is
enabled, rb->nr_pages is always equal to 1.
Arch with CONFIG_PERF_USE_VMALLOC enabled by default:
arc/arm/csky/mips/sh/sparc/xtensa
Arch with CONFIG_PERF_USE_VMALLOC disabled by default:
x86_64/aarch64/...
Fix this problem by using data_page_nr()
[1] https://github.com/draios/sysdig
Fixes: 906010b213 ("perf_event: Provide vmalloc() based mmap() backing")
Signed-off-by: Zhipeng Xie <xiezhipeng1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220209145417.6495-1-xiezhipeng1@huawei.com
