kernel/tools/perf/util/dso.c, branch linux-6.17.y

perf dso: Move build_id to dso_id

2025-07-25T17:37:56Z

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 Link: https://lore.kernel.org/r/20250724163302.596743-7-irogers@google.com Signed-off-by: Namhyung Kim

perf build-id: Change sprintf functions to snprintf

2025-07-25T17:37:13Z

Pass in a size argument rather than implying all build id strings must be SBUILD_ID_SIZE. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-4-irogers@google.com [ fixed some build errors ] Signed-off-by: Namhyung Kim

perf dso: With ref count checking, avoid dso_data holding dso live

2025-07-03T02:05:27Z

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 Link: https://lore.kernel.org/r/20250624190326.2038704-5-irogers@google.com Signed-off-by: Namhyung Kim

perf dso: Minor refactor to allow clang's Wthread-safety analysis

2025-05-21T18:07:13Z

The pattern: ``` if (x) { lock(...) } block1; if (x) { unlock(...) } ``` defeats clang's -Wthread-safety analysis where it complains of locks held on one path and not another. Add helper functions for "block1" then restructure as: ``` if (x) { lock(...); block1(); unlock(...); } else { block1(); } ``` Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Bill Wendling Cc: Chaitanya S Prakash Cc: Fei Lang Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Justin Stitt Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Stephen Brennan Link: https://lore.kernel.org/r/20250519224645.1810891-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf dso: Add support for reading the e_machine type for a dso

2025-03-21T05:58:02Z

For ELF file dsos read the e_machine from the ELF header. For kernel types assume the e_machine matches the perf tool. In other cases return EM_NONE. When reading from the ELF header use DSO__SWAP that may need dso->needs_swap initializing. Factor out dso__swap_init to allow this. Signed-off-by: Ian Rogers Reviewed-by: Namhyung Kim Acked-by: Arnaldo Carvalho de Melo Link: https://lore.kernel.org/r/20250319050741.269828-7-irogers@google.com Signed-off-by: Namhyung Kim

perf dso: Use lock annotations to fix asan deadlock

2025-03-18T05:07:18Z

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 Link: https://lore.kernel.org/r/20250318043151.137973-3-irogers@google.com Signed-off-by: Namhyung Kim

perf symbol: Support .gnu_debugdata for symbols

2025-03-10T21:37:06Z

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 Reviewed-by: Arnaldo Carvalho de Melo Tested-by: Arnaldo Carvalho de Melo Link: https://lore.kernel.org/r/20250307232206.2102440-4-stephen.s.brennan@oracle.com Signed-off-by: Namhyung Kim

perf dso: Constify dso_id

2024-08-19T17:52:13Z

The passed dso_id is copied and so is never an out argument. Remove its mutability. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Anne Macedo Cc: Arnd Bergmann Cc: Athira Rajeev Cc: Casey Chen Cc: Chaitanya S Prakash Cc: Colin Ian King Cc: Dominique Martinet Cc: Ingo Molnar Cc: James Clark Cc: Jann Horn Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Masahiro Yamada Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sun Haiyong Cc: Weilin Wang Cc: Yang Jihong Cc: Yunseong Kim Cc: Ze Gao Link: https://lore.kernel.org/r/20240817064442.2152089-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf dso: Fix build when libunwind is enabled

2024-07-17T20:17:57Z

Now that symsrc_filename is always accessed through an accessor, we also need a free() function for it to avoid the following compilation error: util/unwind-libunwind-local.c:416:12: error: lvalue required as unary ‘&’ operand 416 | zfree(&dso__symsrc_filename(dso)); Fixes: 1553419c3c10 ("perf dso: Fix address sanitizer build") Signed-off-by: James Clark Reviewed-by: Ian Rogers Tested-by: Leo Yan Tested-by: Florian Fainelli Cc: Yunseong Kim Cc: Athira Rajeev Link: https://lore.kernel.org/r/20240715094715.3914813-1-james.clark@linaro.org Signed-off-by: Namhyung Kim

tools/perf: Fix the string match for "/tmp/perf-$PID.map" files in dso__load

2024-06-25T18:00:43Z

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 80d496be89ed ("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: 56cbeacf1435 ("perf probe: Add test for regression introduced by switch to die_get_decl_file()") Signed-off-by: Athira Rajeev Reviewed-by: Chaitanya S Prakash Reviewed-by: Adrian Hunter 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 Link: https://lore.kernel.org/r/20240623064850.83720-1-atrajeev@linux.vnet.ibm.com