Add a new debug option "type-profile" to enable the detailed info during
the type analysis especially for instruction tracking. You can use this
before the command name like 'report' or 'annotate'.
$ perf --debug type-profile annotate --data-type
Committer testing:
First get some memory events:
$ perf mem record ls
Then, without data-type profiling debug:
$ perf annotate --data-type | head
Annotate type: 'struct rtld_global' in /usr/lib64/ld-linux-x86-64.so.2 (1 samples):
============================================================================
samples offset size field
1 0 4336 struct rtld_global {
0 0 0 struct link_namespaces* _dl_ns;
0 2560 8 size_t _dl_nns;
0 2568 40 __rtld_lock_recursive_t _dl_load_lock {
0 2568 40 pthread_mutex_t mutex {
0 2568 40 struct __pthread_mutex_s __data {
0 2568 4 int __lock;
$
And with only data-type profiling:
$ perf --debug type-profile annotate --data-type | head
-----------------------------------------------------------
find_data_type_die [1e67] for reg13873052 (PC) offset=0x150e2 in dl_main
CU die offset: 0x29cd3
found PC-rel by addr=0x34020 offset=0x20
-----------------------------------------------------------
find_data_type_die [2e] for reg12 offset=0 in __GI___readdir64
CU die offset: 0x137a45
frame base: cfa=1 fbreg=-1
found "__futex" in scope=2/2 (die: 0x137ad5) 0(reg12) type=int (die:2a)
-----------------------------------------------------------
find_data_type_die [52] for reg5 offset=0 in __memmove_avx_unaligned_erms
CU die offset: 0x1124ed
no variable found
Annotate type: 'struct rtld_global' in /usr/lib64/ld-linux-x86-64.so.2 (1 samples):
============================================================================
samples offset size field
1 0 4336 struct rtld_global {
0 0 0 struct link_namespaces* _dl_ns;
0 2560 8 size_t _dl_nns;
0 2568 40 __rtld_lock_recursive_t _dl_load_lock {
0 2568 40 pthread_mutex_t mutex {
0 2568 40 struct __pthread_mutex_s __data {
0 2568 4 int __lock;
$
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240319055115.4063940-9-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We want to track type states as instructions are executed. Each
instruction can access compound types like struct or union and load/
store its members to a different location.
The die_deref_ptr_type() is to find a type of memory access with a
pointer variable. If it points to a compound type like struct, the
target memory is a member in the struct. The access will happen with an
offset indicating which member it refers. Let's follow the DWARF info
to figure out the type of the pointer target.
For example, say we have the following code.
struct foo {
int a;
int b;
};
struct foo *p = malloc(sizeof(*p));
p->b = 0;
The last pointer access should produce x86 asm like below:
mov 0x0, 4(%rbx)
And we know %rbx register has a pointer to struct foo. Then offset 4
should return the debug info of member 'b'.
Also variables of compound types can be accessed directly without a
pointer. The die_get_member_type() is to handle a such case.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240319055115.4063940-4-namhyung@kernel.org
[ Check if die_get_real_type() returned NULL ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If the --itrace option is used more than once, the options are
combined, but "i" and "y" (sub-)options can be corrupted because
itrace_do_parse_synth_opts() incorrectly overwrites the period type and
period with default values.
For example, with:
--itrace=i0ns --itrace=e
The processing of "--itrace=e", resets the "i" period from 0 nanoseconds
to the default 100 microseconds.
Fix by performing the default setting of period type and period only if
"i" or "y" are present in the currently processed --itrace value.
Fixes: f6986c95af ("perf session: Add instruction tracing options")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240315071334.3478-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
These were used to build perf to provide defines not available in older
distros, but this was back in 2017, nowadays most the distros that are
supported and I have build containers for work using just the system
headers, so ditch them.
For the few that don't have STATX_MNT_ID{_UNIQUE}, or STATX_MNT_DIOALIGN
add them conditionally.
Some of these older distros may not have things that are used in 'perf
trace', but then they also don't have libtraceevent packages, so don't
build 'perf trace'.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/20240315204835.748716-6-acme@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
These were used to build perf to provide defines not available in older
distros, but this was back in 2017, nowadays all the distros that are
supported and I have build containers for work using just the system
headers, so ditch them.
Some of these older distros may not have things that are used in 'perf
trace', but then they also don't have libtraceevent packages, so don't
build 'perf trace'.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/20240315204835.748716-5-acme@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Builds ok all the way back to these older distros:
1 almalinux:8 : Ok gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-20) , clang version 16.0.6 (Red Hat 16.0.6-2.module_el8.9.0+3621+df7f7146) flex 2.6.1
3 alpine:3.15 : Ok gcc (Alpine 10.3.1_git20211027) 10.3.1 20211027 , Alpine clang version 12.0.1 flex 2.6.4
15 debian:10 : Ok gcc (Debian 8.3.0-6) 8.3.0 , Debian clang version 11.0.1-2~deb10u1 flex 2.6.4
32 opensuse:15.4 : Ok gcc (SUSE Linux) 7.5.0 , clang version 15.0.7 flex 2.6.4
23 fedora:35 : Ok gcc (GCC) 11.3.1 20220421 (Red Hat 11.3.1-3) , clang version 13.0.1 (Fedora 13.0.1-1.fc35) flex 2.6.4
38 ubuntu:18.04 : Ok gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0 flex 2.6.4
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/20240315204835.748716-4-acme@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It is mostly used only to generate string tables, not to build perf, so
move it to the tools/perf/trace/beauty/include/ hierarchy, that is used
just for scraping.
This is a something that should've have happened, as happened with the
linux/socket.h scrapper, do it now as Ian suggested while doing an
audit/refactor session in the headers used by perf.
No other tools/ living code uses it, just <linux/usbdevice_fs.h> coming
from either 'make install_headers' or from the system /usr/include/
directory.
Suggested-by: Ian Rogers <irogers@google.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/CAP-5=fWZVrpRufO4w-S4EcSi9STXcTAN2ERLwTSN7yrSSA-otQ@mail.gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It is mostly used only to generate string tables, not to build perf, so
move it to the tools/perf/trace/beauty/include/ hierarchy, that is used
just for scraping.
This is a something that should've have happened, as happened with the
linux/socket.h scrapper, do it now as Ian suggested while doing an
audit/refactor session in the headers used by perf.
No other tools/ living code uses it, just <linux/mount.h> coming from
either 'make install_headers' or from the system /usr/include/
directory.
Suggested-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/CAP-5=fWZVrpRufO4w-S4EcSi9STXcTAN2ERLwTSN7yrSSA-otQ@mail.gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The tools/include/uapi/linux/mount.h file is mostly used for scrapping
defines into id->string tables, this is the only place were it is being
directly used, stop doing so.
Define MOUNT_ATTR_RELATIME and MOUNT_ATTR__ATIME if not available in the
system's headers.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It is mostly used only to generate string tables, not to build perf, so
move it to the tools/perf/trace/beauty/include/ hierarchy, that is used
just for scraping.
The only case where it was being used to build was in
tools/perf/trace/beauty/sync_file_range.c, because some older systems
doesn't have the SYNC_FILE_RANGE_WRITE_AND_WAIT define, just use the
system's linux/fs.h header instead, defining it if not available.
This is a something that should've have happened, as happened with the
linux/socket.h scrapper, do it now as Ian suggested while doing an
audit/refactor session in the headers used by perf.
No other tools/ living code uses it, just <linux/fs.h> coming from
either 'make install_headers' or from the system /usr/include/
directory.
Suggested-by: Ian Rogers <irogers@google.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/CAP-5=fWZVrpRufO4w-S4EcSi9STXcTAN2ERLwTSN7yrSSA-otQ@mail.gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull smb server updates from Steve French:
- add support for durable file handles (an important data integrity
feature)
- fixes for potential out of bounds issues
- fix possible null dereference in close
- getattr fixes
- trivial typo fix and minor cleanup
* tag 'v6.9-rc-smb3-server-fixes' of git://git.samba.org/ksmbd:
ksmbd: remove module version
ksmbd: fix potencial out-of-bounds when buffer offset is invalid
ksmbd: fix slab-out-of-bounds in smb_strndup_from_utf16()
ksmbd: Fix spelling mistake "connction" -> "connection"
ksmbd: fix possible null-deref in smb_lazy_parent_lease_break_close
ksmbd: add support for durable handles v1/v2
ksmbd: mark SMB2_SESSION_EXPIRED to session when destroying previous session
ksmbd: retrieve number of blocks using vfs_getattr in set_file_allocation_info
ksmbd: replace generic_fillattr with vfs_getattr
Pull trace tool updates from Steven Rostedt:
"Tracing:
- Update makefiles for latency-collector and RTLA, using tools/build/
makefiles like perf does, inheriting its benefits. For example,
having a proper way to handle library dependencies.
- The timerlat tracer has an interface for any tool to use. rtla
timerlat tool uses this interface dispatching its own threads as
workload. But, rtla timerlat could also be used for any other
process. So, add 'rtla timerlat -U' option, allowing the timerlat
tool to measure the latency of any task using the timerlat tracer
interface.
Verification:
- Update makefiles for verification/rv, using tools/build/ makefiles
like perf does, inheriting its benefits. For example, having a
proper way to handle dependencies"
* tag 'trace-tools-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tools/rtla: Add -U/--user-load option to timerlat
tools/verification: Use tools/build makefiles on rv
tools/rtla: Use tools/build makefiles to build rtla
tools/tracing: Use tools/build makefiles on latency-collector
Pull more documentation updates from Jonathan Corbet:
"A handful of late-arriving documentation fixes and enhancements"
* tag 'docs-6.9-2' of git://git.lwn.net/linux:
docs: verify/bisect: remove a level of indenting
docs: verify/bisect: drop 'v' prefix, EOL aspect, and assorted fixes
docs: verify/bisect: check taint flag
docs: verify/bisect: improve install instructions
docs: handling-regressions.rst: Update regzbot command fixed-by to fix
docs: *-regressions.rst: Add colon to regzbot commands
doc: Fix typo in admin-guide/cifs/introduction.rst
README: Fix spelling
The timerlat tracer provides an interface for any application to wait
for the timerlat's periodic wakeup. Currently, rtla timerlat uses it
to dispatch its user-space workload (-u option).
But as the tracer interface is generic, rtla timerlat can also be used
to monitor any workload that uses it. For example, a user might
place their own workload to wait on the tracer interface, and
monitor the results with rtla timerlat.
Add the -U option to rtla timerlat top and hist. With this option, rtla
timerlat will not dispatch its workload but only setting up the
system, waiting for a user to dispatch its workload.
The sample code in this patch is an example of python application
that loops in the timerlat tracer fd.
To use it, dispatch:
# rtla timerlat -U
In a terminal, then run the python program on another terminal,
specifying the CPU to run it. For example, setting on CPU 1:
#./timerlat_load.py 1
Then rtla timerlat will start printing the statistics of the
./timerlat_load.py app.
An interesting point is that the "Ret user Timer Latency" value
is the overall response time of the load. The sample load does
a memory copy to exemplify that.
The stop tracing options on rtla timerlat works in this setup
as well, including auto analysis.
Link: https://lkml.kernel.org/r/36e6bcf18fe15c7601048fd4c65aeb193c502cc8.1707229706.git.bristot@kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Use tools/build/ makefiles to build rtla, inheriting the benefits of
it. For example, having a proper way to handle dependencies.
rtla is built using perf infra-structure when building inside the
kernel tree.
At this point, rtla diverges from perf in two points: Documentation
and tarball generation/build.
At the documentation level, rtla is one step ahead, placing the
documentation at Documentation/tools/rtla/, using the same build
tools as kernel documentation. The idea is to move perf
documentation to the same scheme and then share the same makefiles.
rtla has a tarball target that the (old) RHEL8 uses. The tarball was
kept using a simple standalone makefile for compatibility. The
standalone makefile shares most of the code, e.g., flags, with
regular buildings.
The tarball method was set as deprecated. If necessary, we can make
a rtla tarball like perf, which includes the entire tools/build.
But this would also require changes in the user side (the directory
structure changes, and probably the deps to build the package).
Inspired on perf and objtool.
Link: https://lkml.kernel.org/r/57563abf2715d22515c0c54a87cff3849eca5d52.1710519524.git.bristot@kernel.org
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Use tools/build/ makefiles to build latency-collector, inheriting
the benefits of it. For example: Before this patch, a missing
tracefs/traceevents headers will result in fail like this:
~/linux/tools/tracing/latency $ make
cc -Wall -Wextra -g -O2 -o latency-collector latency-collector.c -lpthread
latency-collector.c:26:10: fatal error: tracefs.h: No such file or directory
26 | #include <tracefs.h>
| ^~~~~~~~~~~
compilation terminated.
make: *** [Makefile:14: latency-collector] Error 1
Which is not that helpful. After this change it reports:
~/linux/tools/tracing/latency# make
Auto-detecting system features:
... libtraceevent: [ OFF ]
... libtracefs: [ OFF ]
libtraceevent is missing. Please install libtraceevent-dev/libtraceevent-devel
libtracefs is missing. Please install libtracefs-dev/libtracefs-devel
Makefile.config:29: *** Please, check the errors above.. Stop.
This type of output is common across other tools in tools/ like perf
and objtool.
Link: https://lkml.kernel.org/r/872420b0880b11304e4ba144a0086c6478c5b469.1710519524.git.bristot@kernel.org
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Pull bcachefs fixes from Kent Overstreet:
"Assorted bugfixes.
Most are fixes for simple assertion pops; the most significant fix is
for a deadlock in recovery when we have to rewrite large numbers of
btree nodes to fix errors. This was incorrectly running out of the
same workqueue as the core interior btree update path - we now give it
its own single threaded workqueue.
This was visible to users as "bch2_btree_update_start(): error:
BCH_ERR_journal_reclaim_would_deadlock" - and then recovery hanging"
* tag 'bcachefs-2024-03-19' of https://evilpiepirate.org/git/bcachefs:
bcachefs: Fix lost wakeup on journal shutdown
bcachefs; Fix deadlock in bch2_btree_update_start()
bcachefs: ratelimit errors from async_btree_node_rewrite
bcachefs: Run check_topology() first
bcachefs: Improve bch2_fatal_error()
bcachefs: Fix lost transaction restart error
bcachefs: Don't corrupt journal keys gap buffer when dropping alloc info
bcachefs: fix for building in userspace
bcachefs: bch2_snapshot_is_ancestor() now safe to call in early recovery
bcachefs: Fix nested transaction restart handling in bch2_bucket_gens_init()
bcachefs: Improve sysfs internal/btree_updates
bcachefs: Split out btree_node_rewrite_worker
bcachefs: Fix locking in bch2_alloc_write_key()
bcachefs: Avoid extent entry type assertions in .invalid()
bcachefs: Fix spurious -BCH_ERR_transaction_restart_nested
bcachefs: Fix check_key_has_snapshot() call
bcachefs: Change "accounting overran journal reservation" to a warning
Pull more ARM SoC updates from Arnd Bergmann:
"These are changes that for some reason ended up not making it into the
first four branches but that should still make it into 6.9:
- A rework of the omap clock support that touches both drivers and
device tree files
- The reset controller branch changes that had a dependency on late
bugfixes. Merging them here avoids a backmerge of 6.8-rc5 into the
drivers branch
- The RISC-V/starfive, RISC-V/microchip and ARM/Broadcom devicetree
changes that got delayed and needed some extra time in linux-next
for wider testing"
* tag 'soc-late-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (31 commits)
soc: fsl: dpio: fix kcalloc() argument order
bus: ts-nbus: Improve error reporting
bus: ts-nbus: Convert to atomic pwm API
riscv: dts: starfive: jh7110: Add camera subsystem nodes
ARM: bcm: stop selecing CONFIG_TICK_ONESHOT
ARM: dts: omap3: Update clksel clocks to use reg instead of ti,bit-shift
ARM: dts: am3: Update clksel clocks to use reg instead of ti,bit-shift
clk: ti: Improve clksel clock bit parsing for reg property
clk: ti: Handle possible address in the node name
dt-bindings: pwm: opencores: Add compatible for StarFive JH8100
dt-bindings: riscv: cpus: reg matches hart ID
reset: Instantiate reset GPIO controller for shared reset-gpios
reset: gpio: Add GPIO-based reset controller
cpufreq: do not open-code of_phandle_args_equal()
of: Add of_phandle_args_equal() helper
reset: simple: add support for Sophgo SG2042
dt-bindings: reset: sophgo: support SG2042
riscv: dts: microchip: add specific compatible for mpfs pdma
riscv: dts: microchip: add missing CAN bus clocks
ARM: brcmstb: Add debug UART entry for 74165
...
Pull more s390 updates from Heiko Carstens:
- Various virtual vs physical address usage fixes
- Add new bitwise types and helper functions and use them in s390
specific drivers and code to make it easier to find virtual vs
physical address usage bugs.
Right now virtual and physical addresses are identical for s390,
except for module, vmalloc, and similar areas. This will be changed,
hopefully with the next merge window, so that e.g. the kernel image
and modules will be located close to each other, allowing for direct
branches and also for some other simplifications.
As a prerequisite this requires to fix all misuses of virtual and
physical addresses. As it turned out people are so used to the
concept that virtual and physical addresses are the same, that new
bugs got added to code which was already fixed. In order to avoid
that even more code gets merged which adds such bugs add and use new
bitwise types, so that sparse can be used to find such usage bugs.
Most likely the new types can go away again after some time
- Provide a simple ARCH_HAS_DEBUG_VIRTUAL implementation
- Fix kprobe branch handling: if an out-of-line single stepped relative
branch instruction has a target address within a certain address area
in the entry code, the program check handler may incorrectly execute
cleanup code as if KVM code was executed, leading to crashes
- Fix reference counting of zcrypt card objects
- Various other small fixes and cleanups
* tag 's390-6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (41 commits)
s390/entry: compare gmap asce to determine guest/host fault
s390/entry: remove OUTSIDE macro
s390/entry: add CIF_SIE flag and remove sie64a() address check
s390/cio: use while (i--) pattern to clean up
s390/raw3270: make class3270 constant
s390/raw3270: improve raw3270_init() readability
s390/tape: make tape_class constant
s390/vmlogrdr: make vmlogrdr_class constant
s390/vmur: make vmur_class constant
s390/zcrypt: make zcrypt_class constant
s390/mm: provide simple ARCH_HAS_DEBUG_VIRTUAL support
s390/vfio_ccw_cp: use new address translation helpers
s390/iucv: use new address translation helpers
s390/ctcm: use new address translation helpers
s390/lcs: use new address translation helpers
s390/qeth: use new address translation helpers
s390/zfcp: use new address translation helpers
s390/tape: fix virtual vs physical address confusion
s390/3270: use new address translation helpers
s390/3215: use new address translation helpers
...
As __assign_str() no longer uses its "src" parameter, there's a check to
make sure nothing depends on it being different than what was passed to
__string(). It originally just compared the pointer passed to __string()
with the pointer passed into __assign_str() via the "src" parameter. But
there's a couple of outliers that just pass in a quoted string constant,
where comparing the pointers is UB to the compiler, as the compiler is
free to create multiple copies of the same string constant.
Instead, just use strcmp(). It may slow down the trace event, but this
will eventually be removed.
Also, fix the issue of passing NULL to strcmp() by adding a WARN_ON() to
make sure that both "src" and the pointer saved in __string() are either
both NULL or have content, and then checking if "src" is not NULL before
performing the strcmp().
Link: https://lore.kernel.org/all/CAHk-=wjxX16kWd=uxG5wzqt=aXoYDf1BgWOKk+qVmAO0zh7sjA@mail.gmail.com/
Fixes: b1afefa62c ("tracing: Use strcmp() in __assign_str() WARN_ON() check")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Namhyung Kim
Ian Rogers
Ethan Adams
Adrian Hunter
James Clark
Arnaldo Carvalho de Melo
Bhaskar Chowdhury
Linus Torvalds
Daniel Bristot de Oliveira
Steven Rostedt (Google)