Messages in this thread |  | | Date | Sun, 17 Jul 2022 11:01:01 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v2] perf trace: Fix SIGSEGV when processing syscall args |
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Em Thu, Jul 07, 2022 at 02:39:00PM +0530, Naveen N. Rao escreveu: > On powerpc, 'perf trace' is crashing with a SIGSEGV when trying to > process a perf.data 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->syscalls.events.sys_enter) > 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 perf.data file, we are not > initializing those properly. Fix the same.
Thanks, applied.
- Arnaldo
> Reported-by: Claudio Carvalho <cclaudio@linux.ibm.com> > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> > --- > 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->syscalls.events.sys_enter = 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->syscalls.events.sys_exit = evsel; > if (evsel == NULL) > evsel = evlist__find_tracepoint_by_name(session->evlist, "syscalls:sys_exit"); > if (evsel && > > base-commit: 52f28b7bac75da9b8508f17438c9a8d83ab48e5d > -- > 2.36.1
--
- Arnaldo
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