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Subject[PATCH v2] perf trace: Fix SIGSEGV when processing syscall args
On powerpc, 'perf trace' is crashing with a SIGSEGV when trying to
process a file created with 'perf trace record -p':

#0 0x00000001225b8988 in syscall_arg__scnprintf_augmented_string <snip> at builtin-trace.c:1492
#1 syscall_arg__scnprintf_filename <snip> at builtin-trace.c:1492
#2 syscall_arg__scnprintf_filename <snip> at builtin-trace.c:1486
#3 0x00000001225bdd9c in syscall_arg_fmt__scnprintf_val <snip> at builtin-trace.c:1973
#4 syscall__scnprintf_args <snip> at builtin-trace.c:2041
#5 0x00000001225bff04 in trace__sys_enter <snip> at builtin-trace.c:2319

That points to the below code in tools/perf/builtin-trace.c:
* If this is raw_syscalls.sys_enter, then it always comes with the 6 possible
* arguments, even if the syscall being handled, say "openat", uses only 4 arguments
* this breaks syscall__augmented_args() check for augmented args, as we calculate
* syscall->args_size using each syscalls:sys_enter_NAME tracefs format file,
* so when handling, say the openat syscall, we end up getting 6 args for the
* raw_syscalls:sys_enter event, when we expected just 4, we end up mistakenly
* thinking that the extra 2 u64 args are the augmented filename, so just check
* here and avoid using augmented syscalls when the evsel is the raw_syscalls one.
if (evsel != trace->
augmented_args = syscall__augmented_args(sc, sample, &augmented_args_size, trace->raw_augmented_syscalls_args_size);

As the comment points out, we should not be trying to augment the args
for raw_syscalls. However, when processing a file, we are not
initializing those properly. Fix the same.

Reported-by: Claudio Carvalho <>
Signed-off-by: Naveen N. Rao <>
tools/perf/builtin-trace.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 897fc504918b91..f075cf37a65ef8 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -4280,6 +4280,7 @@ static int trace__replay(struct trace *trace)
goto out;

evsel = evlist__find_tracepoint_by_name(session->evlist, "raw_syscalls:sys_enter");
+ trace-> = evsel;
/* older kernels have syscalls tp versus raw_syscalls */
if (evsel == NULL)
evsel = evlist__find_tracepoint_by_name(session->evlist, "syscalls:sys_enter");
@@ -4292,6 +4293,7 @@ static int trace__replay(struct trace *trace)

evsel = evlist__find_tracepoint_by_name(session->evlist, "raw_syscalls:sys_exit");
+ trace-> = evsel;
if (evsel == NULL)
evsel = evlist__find_tracepoint_by_name(session->evlist, "syscalls:sys_exit");
if (evsel &&
base-commit: 52f28b7bac75da9b8508f17438c9a8d83ab48e5d

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