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.
Reported-by: Claudio Carvalho <[email protected]>
Signed-off-by: Naveen N. Rao <[email protected]>
---
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
Hello,
On Thu, Jul 7, 2022 at 2:09 AM Naveen N. Rao
<[email protected]> wrote:
>
> 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.
>
> Reported-by: Claudio Carvalho <[email protected]>
> Signed-off-by: Naveen N. Rao <[email protected]>
> ---
> 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 */
Isn't it better to set it after the NULL check below?
> 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;
Ditto.
Thanks,
Namhyung
> if (evsel == NULL)
> evsel = evlist__find_tracepoint_by_name(session->evlist, "syscalls:sys_exit");
> if (evsel &&
>
> base-commit: 52f28b7bac75da9b8508f17438c9a8d83ab48e5d
> --
> 2.36.1
>
Hi Namhyung,
Namhyung Kim wrote:
> Hello,
>
> On Thu, Jul 7, 2022 at 2:09 AM Naveen N. Rao
> <[email protected]> wrote:
>>
>> 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.
>>
>> Reported-by: Claudio Carvalho <[email protected]>
>> Signed-off-by: Naveen N. Rao <[email protected]>
>> ---
>> 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 */
>
> Isn't it better to set it after the NULL check below?
From trace__sys_enter():
/*
* 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);
From the previous discussion [1], it looks like the assumption above is
that sys_enter would be set to raw_syscalls.
As such, I set it before the NULL check below, which ends up falling
back to the non-raw syscalls tracepoint.
Thanks,
Naveen
[1] https://lore.kernel.org/all/[email protected]/
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 <[email protected]>
> Signed-off-by: Naveen N. Rao <[email protected]>
> ---
> 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