dso__get_filename() sets errno to a negative custom DSO_LOAD_ERRNO
value when kernel module decompression fails:
errno = *dso__load_errno(dso); /* e.g. -9996 */
The caller __open_dso() then computes fd = -errno, producing a large
positive value (9996) that looks like a valid file descriptor. This
can cause close_data_fd() to close an unrelated fd used by another
subsystem.
Set errno to EIO instead. The detailed error code is already stored
in dso__load_errno(dso) for diagnostic messages.
Fixes: 1d6b3c9ba7 ("perf tools: Decompress kernel module when reading DSO data")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Several functions cast bpf_prog_info fields (jited_ksyms,
jited_func_lens, jited_prog_insns) from u64 to pointers and
dereference them. These fields are only valid pointers if
bpil_offs_to_addr() converted their file offsets to addresses, which
only happens when the corresponding PERF_BPIL_* bits are set in
info_linear->arrays.
A crafted perf.data can leave these bits unset while setting non-zero
counts and offset values, causing the functions to dereference raw file
offsets as pointers.
Add array bitmask validation to all perf.data processing paths:
- __bpf_event__print_bpf_prog_info(): check JITED_KSYMS and
JITED_FUNC_LENS (changed to take struct perf_bpil *)
- machine__process_bpf_event_load(): check JITED_KSYMS
- bpf_read(): check JITED_INSNS before memcpy from jited_prog_insns
- dso__disassemble_filename(): check JITED_INSNS before returning
jited_prog_insns pointer
Fixes: f8dfeae009 ("perf bpf: Show more BPF program info in print_bpf_prog_info()")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
filename__decompress() has an early return for files that are not
actually compressed, where it calls open() directly. When open()
fails, the function returns -1 but never sets *err. The caller chain
(decompress_kmodule → dso__decompress_kmodule_path → dso__get_filename)
then reads *dso__load_errno(dso) to set errno, but that field was never
populated, so errno gets a stale or zero value.
With errno=0, __open_dso() computes fd = -errno = 0, which is non-
negative, so callers treat fd 0 (stdin) as a valid DSO file descriptor.
Set *err = errno when open() fails on the uncompressed path, matching
the error handling on the compressed path at line 354.
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Fixes: 8b42b7e5e8 ("perf tools: Add is_compressed callback to compressions array")
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
dso__get_filename() allocates name with malloc(PATH_MAX), but the
dso__filename_with_chroot() path replaces name with an asprintf'd
exact-size string (e.g. 8 bytes for "/a/b.ko"). When the DSO needs
decompression, dso__decompress_kmodule_path() writes the temp path
("/tmp/perf-kmod-XXXXXX", 22 bytes) into newpath, and strcpy(name,
newpath) overflows the smaller allocation.
Replace the strcpy with strdup(newpath) + free(name) so the buffer
is always correctly sized for its content.
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Fixes: 1d6b3c9ba7 ("perf tools: Decompress kernel module when reading DSO data")
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
dso__read_running_kernel_build_id() uses sprintf() to format a sysfs
path from machine->root_dir into a PATH_MAX buffer. If root_dir is
close to PATH_MAX in length, appending "/sys/kernel/notes" (18 bytes)
overflows the stack buffer.
Switch to snprintf() with sizeof(path) to prevent the overflow.
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Fixes: cdd059d731 ("perf tools: Move dso_* related functions into dso object")
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
filename__decompress() has an early return path for files that are not
actually compressed. This path returns the fd from open() directly but
never writes to the pathname output parameter, leaving the caller with
an uninitialized buffer despite a successful return.
Callers like dso__decompress_kmodule_path() pass pathname to
decompress_kmodule() which uses it to set the decompressed file path.
If pathname is uninitialized, subsequent operations on the path produce
undefined behavior.
Fix by setting pathname to an empty string on the uncompressed path.
Callers already check for an empty pathname to distinguish temporary
decompressed files (which need unlink) from the original file.
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Fixes: 7ac22b088a ("perf tools: Add filename__decompress function")
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
mkstemp() creates file descriptors without the close-on-exec flag.
These fds leak to child processes spawned during symbol resolution
(addr2line, objdump), wasting descriptors and potentially exposing
temporary file contents.
Replace mkstemp() with mkostemp(tmpbuf, O_CLOEXEC) at all three
call sites:
- filename__decompress() in dso.c
- read_gnu_debugdata() in symbol-elf.c
- kcore__init() in symbol-elf.c
Fixes: 42b3fa6708 ("perf tools: Introduce dso__decompress_kmodule_{fd,path}")
Fixes: b10f74308e ("perf symbol: Support .gnu_debugdata for symbols")
Fixes: afba19d9dc ("perf symbols: Workaround objdump difficulties with kcore")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
open() calls in dso.c and symbol-elf.c omit O_CLOEXEC, which leaks
file descriptors to child processes spawned during symbol resolution
(e.g., addr2line, objdump). This can exhaust the fd limit during
long profiling sessions or when processing many DSOs.
Add O_CLOEXEC to all open() calls in both files (12 call sites).
Fixes: cdd059d731 ("perf tools: Move dso_* related functions into dso object")
Fixes: e5a1845fc0 ("perf symbols: Split out util/symbol-elf.c")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add perf_arch_is_big_endian(), dso__read_e_machine_endian(),
dso__e_machine_endian(), and thread__e_machine_endian() to support
bi-endianness and cross-architecture analysis without breaking the
existing API.
These helpers allow querying the absolute endianness of a DSO or
thread, which is required for tools like Capstone that need to set the
correct disassembly mode.
Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Honglei Wang <jameshongleiwang@126.com>
Cc: Jan Polensky <japo@linux.ibm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The dso__debuginfo() just used the path name to open the file but it may
be outdated. It should check build-ID and use the file in the build-ID
cache if available rather than just using the path name.
Let's factor out dso__get_filename() to avoid code duplicate.
Fixes: 53a61a6ca2 ("perf annotate: Add dso__debuginfo() helper")
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add an implementation of addr2line that uses libdw.
Other addr2line implementations are slow, particularly in the case of
forking addr2line.
Add an implementation that caches the libdw information in the dso and
uses it to find the file and line number information.
Inline information is supported but because cu_walk_functions_at visits
the leaf function last add a inline_list__append_tail to reverse the
lists order.
Committer testing:
# perf probe -x ~/bin/perf libdw__addr2line
Added new event:
probe_perf:libdw_addr2line (on libdw__addr2line in /home/acme/bin/perf)
You can now use it in all perf tools, such as:
perf record -e probe_perf:libdw_addr2line -aR sleep 1
#
# perf stat -e probe_perf:libdw_addr2line perf report -f --dso perf --stdio -s srcfile,srcline
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 4K of event 'cpu/cycles/Pu'
# Event count (approx.): 5535180842
#
# Overhead Source File Source:Line
# ........ ............ ...............
#
99.04% inlineloop.c inlineloop.c:21
0.46% inlineloop.c inlineloop.c:20
#
# (Tip: For tracepoint events, try: perf report -s trace_fields)
#
Performance counter stats for 'perf report -f --dso perf --stdio -s srcfile,srcline':
44 probe_perf:libdw_addr2line
0.037260744 seconds time elapsed
0.025299000 seconds user
0.011918000 seconds sys
#
Adding probes to the other addr2line implementations (llvm__addr2line,
libbfd__addr2line and cmd__addr2line) I noticed some fallbacks to the
llvm one:
Performance counter stats for 'perf report -f --dso perf --stdio -s srcfile,srcline':
44 probe_perf:libdw_addr2line
23 probe_perf:llvm_addr2line
0 probe_perf:libbfd_addr2line
0 probe_perf:cmd_addr2line
Something to investigate further, but at least we don't fallback to the
cmd based one :-)
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Tony Jones <tonyj@suse.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The dso_id previously contained the major, minor, inode and inode
generation information from a mmap2 event - the inode generation would
be zero when reading from /proc/pid/maps. The build_id was in the
dso. With build ID mmap2 events these fields wouldn't be initialized
which would largely mean the special empty case where any dso would
match for equality. This isn't desirable as if a dso is replaced we
want the comparison to yield a difference.
To support detecting the difference between DSOs based on build_id,
move the build_id out of the DSO and into the dso_id. The dso_id is
also stored in the DSO so nothing is lost. Capture in the dso_id what
parts have been initialized and rename dso_id__inject to
dso_id__improve_id so that it is clear the dso_id is being improved
upon with additional information. With the build_id in the dso_id, use
memcmp to compare for equality.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-7-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
With the dso_data embedded in a dso there is a reference counted
pointer to the dso rather than using container_of with reference count
checking. This data can hold the dso live meaning that no dso__put
ever deletes it. Add a check for this case and close the dso_data when
it happens. There isn't an infinite loop as the dso_data clears the
file descriptor prior to putting on the dso.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250624190326.2038704-5-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
dso__list_del with address sanitizer and/or reference count checking
will call dso__put that can call dso__data_close reentrantly trying to
lock the dso__data_open_lock and deadlocking. Switch from pthread
mutexes to perf's mutex so that lock checking is performed in debug
builds. Add lock annotations that diagnosed the problem. Release the
dso__data_open_lock around the dso__put to avoid the deadlock.
Change the declaration of dso__data_get_fd to return a boolean,
indicating the fd is valid and the lock is held, to make it compatible
with the thread safety annotations as a try lock.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250318043151.137973-3-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Fedora introduced a "MiniDebuginfo" feature, in which an LZMA-compressed
ELF file is placed inside a section named ".gnu_debugdata". This file
contains nothing but a symbol table, which can be used to supplement the
.dynsym section which only contains required symbols for runtime.
It is supported by GDB for stack traces, but it should be useful for
tracing as well. Implement support for loading symbols from
.gnu_debugdata.
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20250307232206.2102440-4-stephen.s.brennan@oracle.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Perf test for perf probe of function from different CU fails
as below:
./perf test -vv "test perf probe of function from different CU"
116: test perf probe of function from different CU:
--- start ---
test child forked, pid 2679
Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.Msa7iy89bx/testfile
Error: Failed to add events.
--- Cleaning up ---
"foo" does not hit any event.
Error: Failed to delete events.
---- end(-1) ----
116: test perf probe of function from different CU : FAILED!
The test does below to probe function "foo" :
# gcc -g -Og -flto -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.c
-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
# gcc -g -Og -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.c
-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
# gcc -g -Og -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
# ./perf probe -x /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile foo
Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
Error: Failed to add events.
Perf probe fails to find symbol foo in the executable placed in
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7
Simple reproduce:
# mktemp -d /tmp/perf-checkXXXXXXXXXX
/tmp/perf-checkcWpuLRQI8j
# gcc -g -o test test.c
# cp test /tmp/perf-checkcWpuLRQI8j/
# nm /tmp/perf-checkcWpuLRQI8j/test | grep foo
00000000100006bc T foo
# ./perf probe -x /tmp/perf-checkcWpuLRQI8j/test foo
Failed to find symbol foo in /tmp/perf-checkcWpuLRQI8j/test
Error: Failed to add events.
But it works with any files like /tmp/perf/test. Only for
patterns with "/tmp/perf-", this fails.
Further debugging, commit 80d496be89 ("perf report: Add support
for profiling JIT generated code") added support for profiling JIT
generated code. This patch handles dso's of form
"/tmp/perf-$PID.map" .
The check used "if (strncmp(self->name, "/tmp/perf-", 10) == 0)"
to match "/tmp/perf-$PID.map". With this commit, any dso in
/tmp/perf- folder will be considered separately for processing
(not only JIT created map files ). Fix this by changing the
string pattern to check for "/tmp/perf-%d.map". Add a helper
function is_perf_pid_map_name to do this check. In "struct dso",
dso->long_name holds the long name of the dso file. Since the
/tmp/perf-$PID.map check uses the complete name, use dso___long_name for
the string name.
With the fix,
# ./perf test "test perf probe of function from different CU"
117: test perf probe of function from different CU : Ok
Fixes: 56cbeacf14 ("perf probe: Add test for regression introduced by switch to die_get_decl_file()")
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Reviewed-by: Chaitanya S Prakash <chaitanyas.prakash@arm.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: akanksha@linux.ibm.com
Cc: kjain@linux.ibm.com
Cc: maddy@linux.ibm.com
Cc: disgoel@linux.vnet.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240623064850.83720-1-atrajeev@linux.vnet.ibm.com
DSOs were held on a list for fast iteration and in an rbtree for fast
finds.
Switch to using a lazily sorted array where iteration is just iterating
through the array and binary searches are the same complexity as
searching the rbtree.
The find may need to sort the array first which does increase the
complexity, but add operations have lower complexity and overall the
complexity should remain about the same.
The set name operations on the dso just records that the array is no
longer sorted, avoiding complexity in rebalancing the rbtree.
Tighter locking discipline is enforced to avoid the array being resorted
while long and short names or ids are changed.
The array is smaller in size, replacing 6 pointers with 2, and so even
with extra allocated space in the array, the array may be 50%
unoccupied, the memory saving should be at least 2x.
Committer testing:
On a previous version of this patchset we were getting a lot of warnings
about deleting a DSO still on a list, now it is ok:
root@x1:~# perf probe -l
root@x1:~# perf probe finish_task_switch
Added new event:
probe:finish_task_switch (on finish_task_switch)
You can now use it in all perf tools, such as:
perf record -e probe:finish_task_switch -aR sleep 1
root@x1:~# perf probe -l
probe:finish_task_switch (on finish_task_switch@kernel/sched/core.c)
root@x1:~# perf trace -e probe:finish_task_switch/max-stack=8/ --max-events=1
0.000 migration/0/19 probe:finish_task_switch(__probe_ip: -1894408688)
finish_task_switch.isra.0 ([kernel.kallsyms])
__schedule ([kernel.kallsyms])
schedule ([kernel.kallsyms])
smpboot_thread_fn ([kernel.kallsyms])
kthread ([kernel.kallsyms])
ret_from_fork ([kernel.kallsyms])
ret_from_fork_asm ([kernel.kallsyms])
root@x1:~#
root@x1:~# perf probe -d probe:*
Removed event: probe:finish_task_switch
root@x1:~# perf probe -l
root@x1:~#
I also ran the full 'perf test' suite after applying this one, no
regressions.
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ben Gainey <ben.gainey@arm.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Chengen Du <chengen.du@canonical.com>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: Dima Kogan <dima@secretsauce.net>
Cc: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Li Dong <lidong@vivo.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paran Lee <p4ranlee@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: Sun Haiyong <sunhaiyong@loongson.cn>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: zhaimingbing <zhaimingbing@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20240504213803.218974-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To aggregate accesses to the same data type, add 'data_types' tree in
DSO to maintain data types and find it by name and size.
It might have different data types that happen to have the same name,
so it also compares the size of the type.
Even if it doesn't 100% guarantee, it reduces the possibility of
mis-handling of such conflicts.
And I don't think it's common to have different types with the same
name.
Committer notes:
Very few cases on the Linux kernel, but there are some different types
with the same name, unsure if there is a debug mode in libbpf dedup that
warns about such cases, but there are provisions in pahole for that,
see:
"emit: Notice type shadowing, i.e. multiple types with the same name (enum, struct, union, etc)"
https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=4f332dbfd02072e4f410db7bdcda8d6e3422974b
$ pahole --compile > vmlinux.h
$ rm -f a ; make a
cc a.c -o a
$ grep __[0-9] vmlinux.h
union irte__1 {
struct map_info__1;
struct map_info__1 {
struct map_info__1 * next; /* 0 8 */
$
drivers/iommu/amd/amd_iommu_types.h 'union irte'
include/linux/dmar.h 'struct irte'
include/linux/device-mapper.h:
union map_info {
void *ptr;
};
include/linux/mtd/map.h:
struct map_info {
const char *name;
unsigned long size;
resource_size_t phys;
<SNIP>
kernel/events/uprobes.c:
struct map_info {
struct map_info *next;
struct mm_struct *mm;
unsigned long vaddr;
};
Signed-off-by: Namhyung Kim <namhyung@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: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231213001323.718046-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Update "struct dso" to include new member "is_kmod".
This new field will determine if the file is a kernel
module or not.
To resolve the address from a sample, perf looks at the
DSO maps. In case of address from a kernel module, there
were some address found to be not resolved. This was
observed while running perf test for "Object code reading".
Though the ip falls beteen the start address of the loaded
module (perf map->start ) and end address ( perf map->end),
it was unresolved.
This was happening because in some cases for kernel
modules, address from sample points to stub instructions.
To identify if the DSO is a kernel module, the new field
"is_kmod" is added to "struct dso".
Reported-by: Disha Goel <disgoel@linux.ibm.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: kjain@linux.ibm.com
Cc: maddy@linux.ibm.com
Cc: disgoel@linux.vnet.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230928075213.84392-2-atrajeev@linux.vnet.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Currently it doesn't handle tasks in chroot properly. As filenames in
MMAP records base on their root directory, it's different than what perf
tool can see from outside.
Add filename_with_chroot() helper to deal with those cases. The
function returns a new filename only if it's in a different root
directory. Since it needs to access /proc for the process, it only
works until the task exits.
With this change, I can see symbols in my program like below.
# perf record -o- chroot myroot myprog 3 | perf report -i-
...
#
# Overhead Command Shared Object Symbol
# ........ ....... ................. .............................
#
99.83% myprog myprog [.] loop
0.04% chroot [kernel.kallsyms] [k] fxregs_fixup
0.04% chroot [kernel.kallsyms] [k] rsm_load_seg_32
...
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20220202070828.143303-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently perf saves a build-id with size but old versions assumes the
size of 20. In case the build-id is less than 20 (like for MD5), it'd
fill the rest with 0s.
I saw a problem when old version of perf record saved a binary in the
build-id cache and new version of perf reads the data. The symbols
should be read from the build-id cache (as the path no longer has the
same binary) but it failed due to mismatch in the build-id.
symsrc__init: build id mismatch for /home/namhyung/.debug/.build-id/53/e4c2f42a4c61a2d632d92a72afa08f00000000/elf.
The build-id event in the data has 20 byte build-ids, but it saw a
different size (16) when it reads the build-id of the elf file in the
build-id cache.
$ readelf -n ~/.debug/.build-id/53/e4c2f42a4c61a2d632d92a72afa08f00000000/elf
Displaying notes found in: .note.gnu.build-id
Owner Data size Description
GNU 0x00000010 NT_GNU_BUILD_ID (unique build ID bitstring)
Build ID: 53e4c2f42a4c61a2d632d92a72afa08f
Let's fix this by allowing trailing zeros if the size is different.
Fixes: 39be8d0115 ("perf tools: Pass build_id object to dso__build_id_equal()")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210910224630.1084877-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If libbpf isn't selected, no need for a bunch of related code, that were
not even being used, as code using these perf_env methods was also
enclosed in HAVE_LIBBPF_SUPPORT.
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>
With shorter md5 build ids we need to align their paths properly with
other build ids:
$ perf buildid-list
17f4e448cc746582ea1881528deb549f7fdb3fd5 [kernel.kallsyms]
a50e350e97c43b4708d09bcd85ebfff7 .../tools/perf/buildid-ex-md5
1805c738c8f3ec0f47b7ea09080c28f34d18a82b /usr/lib64/ld-2.31.so
$
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20201013192441.1299447-9-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Arnaldo Carvalho de Melo
Ian Rogers
Namhyung Kim
Stephen Brennan
James Clark
Athira Rajeev
Adrian Hunter
Dave Marchevsky
Riccardo Mancini
Jiri Olsa