kernel/linux.git/tools/perf/util/callchain.c, branch linux-7.1.y

perf sample: Make sure perf_sample__init/exit are used

2026-04-06T06:12:15+00:00

The deferred stack trace code wasn't using perf_sample__init/exit. Add the deferred stack trace clean up to perf_sample__exit which requires proper NULL initialization in perf_sample__init. Make the perf_sample__exit robust to being called more than once by using zfree. Make the error paths in evsel__parse_sample exit the sample. Add a merged_callchain boolean to capture that callchain is allocated, deferred_callchain doen't suffice for this. Pack the struct variables to avoid padding bytes for this. Similiarly powerpc_vpadtl_sample wasn't using perf_sample__init/exit, use it for consistency and potential issues with uninitialized variables. Similarly guest_session__inject_events in builtin-inject wasn't using perf_sample_init/exit. The lifetime management for fetched events is somewhat complex there, but when an event is fetched the sample should be initialized and needs exiting on error. The sample may be left in place so that future injects have access to it. Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf callchain: Refactor callchain option parsing

2026-03-19T21:42:46+00:00

record_opts__parse_callchain is shared by builtin-record and builtin-trace, it is declared in callchain.h. Move the declaration to callchain.c for consistency with the header. In other cases make the option callback a small static stub that then calls into callchain.c. Make the no argument '-g' callchain option just a short-cut for '--call-graph fp' so that there is consistency in how the arguments are handled. This requires the const char* string to be strdup-ed in __parse_callchain_report_opt. For consistency also make parse_callchain_record use strdup and remove some unnecessary casts. Also, be more explicit about the '-g' behavior if there is a .perfconfig file setting. Signed-off-by: Ian Rogers Tested-by: Thomas Richter Signed-off-by: Namhyung Kim

perf callchain: Switch callchain_param_setup from an arch to an e_machine

2026-01-27T04:35:47+00:00

Increase use of e_machine by replacing callchain_param_setup's arch argument to be an e_machine typically read from the session. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Leo Yan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Shimin Guo Cc: Yujie Liu Signed-off-by: Arnaldo Carvalho de Melo

perf map_symbol: Switch from holding maps to holding thread

2026-01-23T19:58:39+00:00

maps may belong to >1 thread. In contexts like symbolization information from the thread may be useful, such as the ELF machine. As the maps can be gained from the thread switch from holding maps in struct map_symbol to holding the thread. Holding the maps in addr_location is also redundant, switch this to using thread__maps. Reviewed-by: James Clark Signed-off-by: Ian Rogers Cc: Aditya Bodkhe Cc: Adrian Hunter Cc: Albert Ou Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Athira Rajeev Cc: Bill Wendling Cc: Dr. David Alan Gilbert Cc: Guo Ren Cc: Howard Chu Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Garry Cc: Julia Lawall Cc: Justin Stitt Cc: Krzysztof Łopatowski Cc: Leo Yan Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Sergei Trofimovich Cc: Shimin Guo Cc: Suchit Karunakaran Cc: Thomas Falcon Cc: Tianyou Li Cc: Will Deacon Cc: Zecheng Li Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Merge deferred user callchains

2025-12-03T05:59:14+00:00

Save samples with deferred callchains in a separate list and deliver them after merging the user callchains. If users don't want to merge they can set tool->merge_deferred_callchains to false to prevent the behavior. With previous result, now perf script will show the merged callchains. $ perf script ... pwd 2312 121.163435: 249113 cpu/cycles/P: ffffffff845b78d8 __build_id_parse.isra.0+0x218 ([kernel.kallsyms]) ffffffff83bb5bf6 perf_event_mmap+0x2e6 ([kernel.kallsyms]) ffffffff83c31959 mprotect_fixup+0x1e9 ([kernel.kallsyms]) ffffffff83c31dc5 do_mprotect_pkey+0x2b5 ([kernel.kallsyms]) ffffffff83c3206f __x64_sys_mprotect+0x1f ([kernel.kallsyms]) ffffffff845e6692 do_syscall_64+0x62 ([kernel.kallsyms]) ffffffff8360012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms]) 7f18fe337fa7 mprotect+0x7 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) 7f18fe330e0f _dl_sysdep_start+0x7f (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) 7f18fe331448 _dl_start_user+0x0 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) ... The old output can be get using --no-merge-callchain option. Also perf report can get the user callchain entry at the end. $ perf report --no-children --stdio -q -S __build_id_parse.isra.0 # symbol: __build_id_parse.isra.0 8.40% pwd [kernel.kallsyms] | ---__build_id_parse.isra.0 perf_event_mmap mprotect_fixup do_mprotect_pkey __x64_sys_mprotect do_syscall_64 entry_SYSCALL_64_after_hwframe mprotect _dl_sysdep_start _dl_start_user Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf record: Add --call-graph fp,defer option for deferred callchains

2025-12-03T05:59:13+00:00

Add a new callchain record mode option for deferred callchains. For now it only works with FP (frame-pointer) mode. And add the missing feature detection logic to clear the flag on old kernels. $ perf record --call-graph fp,defer -vv true ... ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) { sample_period, sample_freq } 4000 sample_type IP|TID|TIME|CALLCHAIN|PERIOD read_format ID|LOST disabled 1 inherit 1 mmap 1 comm 1 freq 1 enable_on_exec 1 task 1 sample_id_all 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 defer_callchain 1 defer_output 1 ------------------------------------------------------------ sys_perf_event_open: pid 162755 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -22 switching off deferred callchain support Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf report: Use map_symbol__copy() when copying callchains

2025-03-07T22:06:56+00:00

It seems there are places to miss updating refcount of maps. Let's use map_symbol__copy() helper to properly copy them with refcounts updated. Link: https://lore.kernel.org/r/20250307061250.320849-1-namhyung@kernel.org Signed-off-by: Namhyung Kim

perf callchain: Allow symbols to be optional when resolving a callchain

2024-09-10T20:32:47+00:00

In uses like 'perf inject' it is not necessary to gather the symbol for each call chain location, the map for the sample IP is wanted so that build IDs and the like can be injected. Make gathering the symbol in the callchain_cursor optional. For a 'perf inject -B' command this lowers the peak RSS from 54.1MB to 29.6MB by avoiding loading symbols. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Anne Macedo Cc: Casey Chen Cc: Colin Ian King Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Peter Zijlstra Cc: Sun Haiyong Link: https://lore.kernel.org/r/20240909203740.143492-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Add a for_each callback style API

2024-08-13T18:28:19+00:00

Add a for_each callback style API to callchain with sample__for_each_callchain_node(). Possibly in the future such an API can avoid the overhead of constructing the call chain list. Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Casey Chen Cc: Colin Ian King Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Peter Zijlstra Cc: Tom Zanussi Link: https://lore.kernel.org/r/20240812224119.744968-1-irogers@google.com [ Split from a larger patch that introduced the API and use it ] Signed-off-by: Arnaldo Carvalho de Melo

perf tool: fix dereferencing NULL al->maps

2024-07-26T18:12:16+00:00

With 0dd5041c9a0e ("perf addr_location: Add init/exit/copy functions"), when cpumode is 3 (macro PERF_RECORD_MISC_HYPERVISOR), thread__find_map() could return with al->maps being NULL. The path below could add a callchain_cursor_node with NULL ms.maps. add_callchain_ip() thread__find_symbol(.., &al) thread__find_map(.., &al) // al->maps becomes NULL ms.maps = maps__get(al.maps) callchain_cursor_append(..., &ms, ...) node->ms.maps = maps__get(ms->maps) Then the path below would dereference NULL maps and get segfault. fill_callchain_info() maps__machine(node->ms.maps); Fix it by checking if maps is NULL in fill_callchain_info(). Fixes: 0dd5041c9a0e ("perf addr_location: Add init/exit/copy functions") Signed-off-by: Casey Chen Reviewed-by: Ian Rogers Reviewed-by: Arnaldo Carvalho de Melo Acked-by: Namhyung Kim Cc: yzhong@purestorage.com Link: https://lore.kernel.org/r/20240722211548.61455-1-cachen@purestorage.com Signed-off-by: Namhyung Kim