When --overwrite and --max-size options of perf record are used together,
a segmentation fault occurs. The following is an example:
# perf record -e sched:sched* --overwrite --max-size 1K -a -- sleep 1
[ perf record: Woken up 1 times to write data ]
perf: Segmentation fault
Obtained 12 stack frames.
./perf/perf(+0x197673) [0x55f99710b673]
/lib/x86_64-linux-gnu/libc.so.6(+0x3ef0f) [0x7fa45f3cff0f]
./perf/perf(+0x8eb40) [0x55f997002b40]
./perf/perf(+0x1f6882) [0x55f99716a882]
./perf/perf(+0x794c2) [0x55f996fed4c2]
./perf/perf(+0x7b7c7) [0x55f996fef7c7]
./perf/perf(+0x9074b) [0x55f99700474b]
./perf/perf(+0x12e23c) [0x55f9970a223c]
./perf/perf(+0x12e54a) [0x55f9970a254a]
./perf/perf(+0x7db60) [0x55f996ff1b60]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe6) [0x7fa45f3b2c86]
./perf/perf(+0x7dfe9) [0x55f996ff1fe9]
Segmentation fault (core dumped)
backtrace of the core file is as follows:
(gdb) bt
#0 record__bytes_written (rec=0x55f99755a200 <record>) at builtin-record.c:234
#1 record__output_max_size_exceeded (rec=0x55f99755a200 <record>) at builtin-record.c:242
#2 record__write (map=0x0, size=12816, bf=0x55f9978da2e0, rec=0x55f99755a200 <record>) at builtin-record.c:263
#3 process_synthesized_event (tool=tool@entry=0x55f99755a200 <record>, event=event@entry=0x55f9978da2e0, sample=sample@entry=0x0, machine=machine@entry=0x55f997893658) at builtin-record.c:618
#4 0x000055f99716a883 in __perf_event__synthesize_id_index (tool=tool@entry=0x55f99755a200 <record>, process=process@entry=0x55f997002aa0 <process_synthesized_event>, evlist=0x55f9978928b0, machine=machine@entry=0x55f997893658,
from=from@entry=0) at util/synthetic-events.c:1895
#5 0x000055f99716a91f in perf_event__synthesize_id_index (tool=tool@entry=0x55f99755a200 <record>, process=process@entry=0x55f997002aa0 <process_synthesized_event>, evlist=<optimized out>, machine=machine@entry=0x55f997893658)
at util/synthetic-events.c:1905
#6 0x000055f996fed4c3 in record__synthesize (tail=tail@entry=true, rec=0x55f99755a200 <record>) at builtin-record.c:1997
#7 0x000055f996fef7c8 in __cmd_record (argc=argc@entry=2, argv=argv@entry=0x7ffc67551260, rec=0x55f99755a200 <record>) at builtin-record.c:2802
#8 0x000055f99700474c in cmd_record (argc=<optimized out>, argv=0x7ffc67551260) at builtin-record.c:4258
#9 0x000055f9970a223d in run_builtin (p=0x55f997564d88 <commands+264>, argc=10, argv=0x7ffc67551260) at perf.c:330
#10 0x000055f9970a254b in handle_internal_command (argc=10, argv=0x7ffc67551260) at perf.c:384
#11 0x000055f996ff1b61 in run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:428
#12 main (argc=<optimized out>, argv=0x7ffc67551260) at perf.c:562
The reason is that record__bytes_written accesses the freed memory rec->thread_data,
The process is as follows:
__cmd_record
-> record__free_thread_data
-> zfree(&rec->thread_data) // free rec->thread_data
-> record__synthesize
-> perf_event__synthesize_id_index
-> process_synthesized_event
-> record__write
-> record__bytes_written // access rec->thread_data
We add a member variable "thread_bytes_written" in the struct "record"
to save the data size written by the threads.
Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size")
Signed-off-by: Yang Jihong <[email protected]>
---
Changes since v2:
- Save data size written by threads to calculate the correct total data size.
- Update commit message.
Changes since v1:
- Add variable check in record__bytes_written for code hardening.
- Save bytes_written separately to reduce one calculation.
- Remove rec->opts.tail_synthesize check.
tools/perf/builtin-record.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 29dcd454b8e2..8374117e66f6 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -154,6 +154,7 @@ struct record {
struct perf_tool tool;
struct record_opts opts;
u64 bytes_written;
+ u64 thread_bytes_written;
struct perf_data data;
struct auxtrace_record *itr;
struct evlist *evlist;
@@ -226,14 +227,7 @@ static bool switch_output_time(struct record *rec)
static u64 record__bytes_written(struct record *rec)
{
- int t;
- u64 bytes_written = rec->bytes_written;
- struct record_thread *thread_data = rec->thread_data;
-
- for (t = 0; t < rec->nr_threads; t++)
- bytes_written += thread_data[t].bytes_written;
-
- return bytes_written;
+ return rec->bytes_written + rec->thread_bytes_written;
}
static bool record__output_max_size_exceeded(struct record *rec)
@@ -255,10 +249,12 @@ static int record__write(struct record *rec, struct mmap *map __maybe_unused,
return -1;
}
- if (map && map->file)
+ if (map && map->file) {
thread->bytes_written += size;
- else
+ rec->thread_bytes_written += size;
+ } else {
rec->bytes_written += size;
+ }
if (record__output_max_size_exceeded(rec) && !done) {
fprintf(stderr, "[ perf record: perf size limit reached (%" PRIu64 " KB),"
--
2.30.GIT
Hello,
The data written by the thread (data.X file) has been saved as
recommended in v2 patch. Please check whether it is feasible. Thank you.
Thanks,
Yang
On 2023/1/13 15:38, Yang Jihong wrote:
> When --overwrite and --max-size options of perf record are used together,
> a segmentation fault occurs. The following is an example:
>
> # perf record -e sched:sched* --overwrite --max-size 1K -a -- sleep 1
> [ perf record: Woken up 1 times to write data ]
> perf: Segmentation fault
> Obtained 12 stack frames.
> ./perf/perf(+0x197673) [0x55f99710b673]
> /lib/x86_64-linux-gnu/libc.so.6(+0x3ef0f) [0x7fa45f3cff0f]
> ./perf/perf(+0x8eb40) [0x55f997002b40]
> ./perf/perf(+0x1f6882) [0x55f99716a882]
> ./perf/perf(+0x794c2) [0x55f996fed4c2]
> ./perf/perf(+0x7b7c7) [0x55f996fef7c7]
> ./perf/perf(+0x9074b) [0x55f99700474b]
> ./perf/perf(+0x12e23c) [0x55f9970a223c]
> ./perf/perf(+0x12e54a) [0x55f9970a254a]
> ./perf/perf(+0x7db60) [0x55f996ff1b60]
> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe6) [0x7fa45f3b2c86]
> ./perf/perf(+0x7dfe9) [0x55f996ff1fe9]
> Segmentation fault (core dumped)
>
> backtrace of the core file is as follows:
>
> (gdb) bt
> #0 record__bytes_written (rec=0x55f99755a200 <record>) at builtin-record.c:234
> #1 record__output_max_size_exceeded (rec=0x55f99755a200 <record>) at builtin-record.c:242
> #2 record__write (map=0x0, size=12816, bf=0x55f9978da2e0, rec=0x55f99755a200 <record>) at builtin-record.c:263
> #3 process_synthesized_event (tool=tool@entry=0x55f99755a200 <record>, event=event@entry=0x55f9978da2e0, sample=sample@entry=0x0, machine=machine@entry=0x55f997893658) at builtin-record.c:618
> #4 0x000055f99716a883 in __perf_event__synthesize_id_index (tool=tool@entry=0x55f99755a200 <record>, process=process@entry=0x55f997002aa0 <process_synthesized_event>, evlist=0x55f9978928b0, machine=machine@entry=0x55f997893658,
> from=from@entry=0) at util/synthetic-events.c:1895
> #5 0x000055f99716a91f in perf_event__synthesize_id_index (tool=tool@entry=0x55f99755a200 <record>, process=process@entry=0x55f997002aa0 <process_synthesized_event>, evlist=<optimized out>, machine=machine@entry=0x55f997893658)
> at util/synthetic-events.c:1905
> #6 0x000055f996fed4c3 in record__synthesize (tail=tail@entry=true, rec=0x55f99755a200 <record>) at builtin-record.c:1997
> #7 0x000055f996fef7c8 in __cmd_record (argc=argc@entry=2, argv=argv@entry=0x7ffc67551260, rec=0x55f99755a200 <record>) at builtin-record.c:2802
> #8 0x000055f99700474c in cmd_record (argc=<optimized out>, argv=0x7ffc67551260) at builtin-record.c:4258
> #9 0x000055f9970a223d in run_builtin (p=0x55f997564d88 <commands+264>, argc=10, argv=0x7ffc67551260) at perf.c:330
> #10 0x000055f9970a254b in handle_internal_command (argc=10, argv=0x7ffc67551260) at perf.c:384
> #11 0x000055f996ff1b61 in run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:428
> #12 main (argc=<optimized out>, argv=0x7ffc67551260) at perf.c:562
>
> The reason is that record__bytes_written accesses the freed memory rec->thread_data,
> The process is as follows:
> __cmd_record
> -> record__free_thread_data
> -> zfree(&rec->thread_data) // free rec->thread_data
> -> record__synthesize
> -> perf_event__synthesize_id_index
> -> process_synthesized_event
> -> record__write
> -> record__bytes_written // access rec->thread_data
>
> We add a member variable "thread_bytes_written" in the struct "record"
> to save the data size written by the threads.
>
> Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size")
> Signed-off-by: Yang Jihong <[email protected]>
> ---
>
> Changes since v2:
> - Save data size written by threads to calculate the correct total data size.
> - Update commit message.
>
> Changes since v1:
> - Add variable check in record__bytes_written for code hardening.
> - Save bytes_written separately to reduce one calculation.
> - Remove rec->opts.tail_synthesize check.
>
> tools/perf/builtin-record.c | 16 ++++++----------
> 1 file changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 29dcd454b8e2..8374117e66f6 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -154,6 +154,7 @@ struct record {
> struct perf_tool tool;
> struct record_opts opts;
> u64 bytes_written;
> + u64 thread_bytes_written;
> struct perf_data data;
> struct auxtrace_record *itr;
> struct evlist *evlist;
> @@ -226,14 +227,7 @@ static bool switch_output_time(struct record *rec)
>
> static u64 record__bytes_written(struct record *rec)
> {
> - int t;
> - u64 bytes_written = rec->bytes_written;
> - struct record_thread *thread_data = rec->thread_data;
> -
> - for (t = 0; t < rec->nr_threads; t++)
> - bytes_written += thread_data[t].bytes_written;
> -
> - return bytes_written;
> + return rec->bytes_written + rec->thread_bytes_written;
> }
>
> static bool record__output_max_size_exceeded(struct record *rec)
> @@ -255,10 +249,12 @@ static int record__write(struct record *rec, struct mmap *map __maybe_unused,
> return -1;
> }
>
> - if (map && map->file)
> + if (map && map->file) {
> thread->bytes_written += size;
> - else
> + rec->thread_bytes_written += size;
> + } else {
> rec->bytes_written += size;
> + }
>
> if (record__output_max_size_exceeded(rec) && !done) {
> fprintf(stderr, "[ perf record: perf size limit reached (%" PRIu64 " KB),"
>
Hello,
Ping again, please take time to review, thanks.
Thanks,
Yang
On 2023/1/28 9:27, Yang Jihong wrote:
> Hello,
>
> The data written by the thread (data.X file) has been saved as
> recommended in v2 patch. Please check whether it is feasible. Thank you.
>
> Thanks,
> Yang
>
> On 2023/1/13 15:38, Yang Jihong wrote:
>> When --overwrite and --max-size options of perf record are used together,
>> a segmentation fault occurs. The following is an example:
>>
>> # perf record -e sched:sched* --overwrite --max-size 1K -a -- sleep 1
>> [ perf record: Woken up 1 times to write data ]
>> perf: Segmentation fault
>> Obtained 12 stack frames.
>> ./perf/perf(+0x197673) [0x55f99710b673]
>> /lib/x86_64-linux-gnu/libc.so.6(+0x3ef0f) [0x7fa45f3cff0f]
>> ./perf/perf(+0x8eb40) [0x55f997002b40]
>> ./perf/perf(+0x1f6882) [0x55f99716a882]
>> ./perf/perf(+0x794c2) [0x55f996fed4c2]
>> ./perf/perf(+0x7b7c7) [0x55f996fef7c7]
>> ./perf/perf(+0x9074b) [0x55f99700474b]
>> ./perf/perf(+0x12e23c) [0x55f9970a223c]
>> ./perf/perf(+0x12e54a) [0x55f9970a254a]
>> ./perf/perf(+0x7db60) [0x55f996ff1b60]
>> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe6)
>> [0x7fa45f3b2c86]
>> ./perf/perf(+0x7dfe9) [0x55f996ff1fe9]
>> Segmentation fault (core dumped)
>>
>> backtrace of the core file is as follows:
>>
>> (gdb) bt
>> #0 record__bytes_written (rec=0x55f99755a200 <record>) at
>> builtin-record.c:234
>> #1 record__output_max_size_exceeded (rec=0x55f99755a200 <record>)
>> at builtin-record.c:242
>> #2 record__write (map=0x0, size=12816, bf=0x55f9978da2e0,
>> rec=0x55f99755a200 <record>) at builtin-record.c:263
>> #3 process_synthesized_event (tool=tool@entry=0x55f99755a200
>> <record>, event=event@entry=0x55f9978da2e0, sample=sample@entry=0x0,
>> machine=machine@entry=0x55f997893658) at builtin-record.c:618
>> #4 0x000055f99716a883 in __perf_event__synthesize_id_index
>> (tool=tool@entry=0x55f99755a200 <record>,
>> process=process@entry=0x55f997002aa0 <process_synthesized_event>,
>> evlist=0x55f9978928b0, machine=machine@entry=0x55f997893658,
>> from=from@entry=0) at util/synthetic-events.c:1895
>> #5 0x000055f99716a91f in perf_event__synthesize_id_index
>> (tool=tool@entry=0x55f99755a200 <record>,
>> process=process@entry=0x55f997002aa0 <process_synthesized_event>,
>> evlist=<optimized out>, machine=machine@entry=0x55f997893658)
>> at util/synthetic-events.c:1905
>> #6 0x000055f996fed4c3 in record__synthesize (tail=tail@entry=true,
>> rec=0x55f99755a200 <record>) at builtin-record.c:1997
>> #7 0x000055f996fef7c8 in __cmd_record (argc=argc@entry=2,
>> argv=argv@entry=0x7ffc67551260, rec=0x55f99755a200 <record>) at
>> builtin-record.c:2802
>> #8 0x000055f99700474c in cmd_record (argc=<optimized out>,
>> argv=0x7ffc67551260) at builtin-record.c:4258
>> #9 0x000055f9970a223d in run_builtin (p=0x55f997564d88
>> <commands+264>, argc=10, argv=0x7ffc67551260) at perf.c:330
>> #10 0x000055f9970a254b in handle_internal_command (argc=10,
>> argv=0x7ffc67551260) at perf.c:384
>> #11 0x000055f996ff1b61 in run_argv (argcp=<synthetic pointer>,
>> argv=<synthetic pointer>) at perf.c:428
>> #12 main (argc=<optimized out>, argv=0x7ffc67551260) at perf.c:562
>>
>> The reason is that record__bytes_written accesses the freed memory
>> rec->thread_data,
>> The process is as follows:
>> __cmd_record
>> -> record__free_thread_data
>> -> zfree(&rec->thread_data) // free rec->thread_data
>> -> record__synthesize
>> -> perf_event__synthesize_id_index
>> -> process_synthesized_event
>> -> record__write
>> -> record__bytes_written // access rec->thread_data
>>
>> We add a member variable "thread_bytes_written" in the struct "record"
>> to save the data size written by the threads.
>>
>> Fixes: 6d57581659f7 ("perf record: Add support for limit perf output
>> file size")
>> Signed-off-by: Yang Jihong <[email protected]>
>> ---
>>
>> Changes since v2:
>> - Save data size written by threads to calculate the correct total
>> data size.
>> - Update commit message.
>>
>> Changes since v1:
>> - Add variable check in record__bytes_written for code hardening.
>> - Save bytes_written separately to reduce one calculation.
>> - Remove rec->opts.tail_synthesize check.
>>
>> tools/perf/builtin-record.c | 16 ++++++----------
>> 1 file changed, 6 insertions(+), 10 deletions(-)
>>
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index 29dcd454b8e2..8374117e66f6 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -154,6 +154,7 @@ struct record {
>> struct perf_tool tool;
>> struct record_opts opts;
>> u64 bytes_written;
>> + u64 thread_bytes_written;
>> struct perf_data data;
>> struct auxtrace_record *itr;
>> struct evlist *evlist;
>> @@ -226,14 +227,7 @@ static bool switch_output_time(struct record *rec)
>> static u64 record__bytes_written(struct record *rec)
>> {
>> - int t;
>> - u64 bytes_written = rec->bytes_written;
>> - struct record_thread *thread_data = rec->thread_data;
>> -
>> - for (t = 0; t < rec->nr_threads; t++)
>> - bytes_written += thread_data[t].bytes_written;
>> -
>> - return bytes_written;
>> + return rec->bytes_written + rec->thread_bytes_written;
>> }
>> static bool record__output_max_size_exceeded(struct record *rec)
>> @@ -255,10 +249,12 @@ static int record__write(struct record *rec,
>> struct mmap *map __maybe_unused,
>> return -1;
>> }
>> - if (map && map->file)
>> + if (map && map->file) {
>> thread->bytes_written += size;
>> - else
>> + rec->thread_bytes_written += size;
>> + } else {
>> rec->bytes_written += size;
>> + }
>> if (record__output_max_size_exceeded(rec) && !done) {
>> fprintf(stderr, "[ perf record: perf size limit reached (%"
>> PRIu64 " KB),"
>>
>
> .
Hello,
On Sun, Feb 5, 2023 at 5:29 PM Yang Jihong <[email protected]> wrote:
>
> Hello,
>
> Ping again, please take time to review, thanks.
Sorry for the late reply. Now it looks good to me.
>
>
> Thanks,
> Yang
>
>
> On 2023/1/28 9:27, Yang Jihong wrote:
> > Hello,
> >
> > The data written by the thread (data.X file) has been saved as
> > recommended in v2 patch. Please check whether it is feasible. Thank you.
> >
> > Thanks,
> > Yang
> >
> > On 2023/1/13 15:38, Yang Jihong wrote:
> >> When --overwrite and --max-size options of perf record are used together,
> >> a segmentation fault occurs. The following is an example:
> >>
> >> # perf record -e sched:sched* --overwrite --max-size 1K -a -- sleep 1
> >> [ perf record: Woken up 1 times to write data ]
> >> perf: Segmentation fault
> >> Obtained 12 stack frames.
> >> ./perf/perf(+0x197673) [0x55f99710b673]
> >> /lib/x86_64-linux-gnu/libc.so.6(+0x3ef0f) [0x7fa45f3cff0f]
> >> ./perf/perf(+0x8eb40) [0x55f997002b40]
> >> ./perf/perf(+0x1f6882) [0x55f99716a882]
> >> ./perf/perf(+0x794c2) [0x55f996fed4c2]
> >> ./perf/perf(+0x7b7c7) [0x55f996fef7c7]
> >> ./perf/perf(+0x9074b) [0x55f99700474b]
> >> ./perf/perf(+0x12e23c) [0x55f9970a223c]
> >> ./perf/perf(+0x12e54a) [0x55f9970a254a]
> >> ./perf/perf(+0x7db60) [0x55f996ff1b60]
> >> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe6)
> >> [0x7fa45f3b2c86]
> >> ./perf/perf(+0x7dfe9) [0x55f996ff1fe9]
> >> Segmentation fault (core dumped)
> >>
> >> backtrace of the core file is as follows:
> >>
> >> (gdb) bt
> >> #0 record__bytes_written (rec=0x55f99755a200 <record>) at
> >> builtin-record.c:234
> >> #1 record__output_max_size_exceeded (rec=0x55f99755a200 <record>)
> >> at builtin-record.c:242
> >> #2 record__write (map=0x0, size=12816, bf=0x55f9978da2e0,
> >> rec=0x55f99755a200 <record>) at builtin-record.c:263
> >> #3 process_synthesized_event (tool=tool@entry=0x55f99755a200
> >> <record>, event=event@entry=0x55f9978da2e0, sample=sample@entry=0x0,
> >> machine=machine@entry=0x55f997893658) at builtin-record.c:618
> >> #4 0x000055f99716a883 in __perf_event__synthesize_id_index
> >> (tool=tool@entry=0x55f99755a200 <record>,
> >> process=process@entry=0x55f997002aa0 <process_synthesized_event>,
> >> evlist=0x55f9978928b0, machine=machine@entry=0x55f997893658,
> >> from=from@entry=0) at util/synthetic-events.c:1895
> >> #5 0x000055f99716a91f in perf_event__synthesize_id_index
> >> (tool=tool@entry=0x55f99755a200 <record>,
> >> process=process@entry=0x55f997002aa0 <process_synthesized_event>,
> >> evlist=<optimized out>, machine=machine@entry=0x55f997893658)
> >> at util/synthetic-events.c:1905
> >> #6 0x000055f996fed4c3 in record__synthesize (tail=tail@entry=true,
> >> rec=0x55f99755a200 <record>) at builtin-record.c:1997
> >> #7 0x000055f996fef7c8 in __cmd_record (argc=argc@entry=2,
> >> argv=argv@entry=0x7ffc67551260, rec=0x55f99755a200 <record>) at
> >> builtin-record.c:2802
> >> #8 0x000055f99700474c in cmd_record (argc=<optimized out>,
> >> argv=0x7ffc67551260) at builtin-record.c:4258
> >> #9 0x000055f9970a223d in run_builtin (p=0x55f997564d88
> >> <commands+264>, argc=10, argv=0x7ffc67551260) at perf.c:330
> >> #10 0x000055f9970a254b in handle_internal_command (argc=10,
> >> argv=0x7ffc67551260) at perf.c:384
> >> #11 0x000055f996ff1b61 in run_argv (argcp=<synthetic pointer>,
> >> argv=<synthetic pointer>) at perf.c:428
> >> #12 main (argc=<optimized out>, argv=0x7ffc67551260) at perf.c:562
> >>
> >> The reason is that record__bytes_written accesses the freed memory
> >> rec->thread_data,
> >> The process is as follows:
> >> __cmd_record
> >> -> record__free_thread_data
> >> -> zfree(&rec->thread_data) // free rec->thread_data
> >> -> record__synthesize
> >> -> perf_event__synthesize_id_index
> >> -> process_synthesized_event
> >> -> record__write
> >> -> record__bytes_written // access rec->thread_data
> >>
> >> We add a member variable "thread_bytes_written" in the struct "record"
> >> to save the data size written by the threads.
> >>
> >> Fixes: 6d57581659f7 ("perf record: Add support for limit perf output
> >> file size")
> >> Signed-off-by: Yang Jihong <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Thanks,
Namhyung
> >> ---
> >>
> >> Changes since v2:
> >> - Save data size written by threads to calculate the correct total
> >> data size.
> >> - Update commit message.
> >>
> >> Changes since v1:
> >> - Add variable check in record__bytes_written for code hardening.
> >> - Save bytes_written separately to reduce one calculation.
> >> - Remove rec->opts.tail_synthesize check.
> >>
> >> tools/perf/builtin-record.c | 16 ++++++----------
> >> 1 file changed, 6 insertions(+), 10 deletions(-)
> >>
> >> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> >> index 29dcd454b8e2..8374117e66f6 100644
> >> --- a/tools/perf/builtin-record.c
> >> +++ b/tools/perf/builtin-record.c
> >> @@ -154,6 +154,7 @@ struct record {
> >> struct perf_tool tool;
> >> struct record_opts opts;
> >> u64 bytes_written;
> >> + u64 thread_bytes_written;
> >> struct perf_data data;
> >> struct auxtrace_record *itr;
> >> struct evlist *evlist;
> >> @@ -226,14 +227,7 @@ static bool switch_output_time(struct record *rec)
> >> static u64 record__bytes_written(struct record *rec)
> >> {
> >> - int t;
> >> - u64 bytes_written = rec->bytes_written;
> >> - struct record_thread *thread_data = rec->thread_data;
> >> -
> >> - for (t = 0; t < rec->nr_threads; t++)
> >> - bytes_written += thread_data[t].bytes_written;
> >> -
> >> - return bytes_written;
> >> + return rec->bytes_written + rec->thread_bytes_written;
> >> }
> >> static bool record__output_max_size_exceeded(struct record *rec)
> >> @@ -255,10 +249,12 @@ static int record__write(struct record *rec,
> >> struct mmap *map __maybe_unused,
> >> return -1;
> >> }
> >> - if (map && map->file)
> >> + if (map && map->file) {
> >> thread->bytes_written += size;
> >> - else
> >> + rec->thread_bytes_written += size;
> >> + } else {
> >> rec->bytes_written += size;
> >> + }
> >> if (record__output_max_size_exceeded(rec) && !done) {
> >> fprintf(stderr, "[ perf record: perf size limit reached (%"
> >> PRIu64 " KB),"
> >>
> >
> > .
Hello,
On 2023/2/6 10:44, Namhyung Kim wrote:
> Hello,
>
> On Sun, Feb 5, 2023 at 5:29 PM Yang Jihong <[email protected]> wrote:
>>
>> Hello,
>>
>> Ping again, please take time to review, thanks.
>
> Sorry for the late reply. Now it looks good to me.
Thanks for the review.
Thanks,
Yang.
>
>>
>>
>> Thanks,
>> Yang
>>
>>
>> On 2023/1/28 9:27, Yang Jihong wrote:
>>> Hello,
>>>
>>> The data written by the thread (data.X file) has been saved as
>>> recommended in v2 patch. Please check whether it is feasible. Thank you.
>>>
>>> Thanks,
>>> Yang
>>>
>>> On 2023/1/13 15:38, Yang Jihong wrote:
>>>> When --overwrite and --max-size options of perf record are used together,
>>>> a segmentation fault occurs. The following is an example:
>>>>
>>>> # perf record -e sched:sched* --overwrite --max-size 1K -a -- sleep 1
>>>> [ perf record: Woken up 1 times to write data ]
>>>> perf: Segmentation fault
>>>> Obtained 12 stack frames.
>>>> ./perf/perf(+0x197673) [0x55f99710b673]
>>>> /lib/x86_64-linux-gnu/libc.so.6(+0x3ef0f) [0x7fa45f3cff0f]
>>>> ./perf/perf(+0x8eb40) [0x55f997002b40]
>>>> ./perf/perf(+0x1f6882) [0x55f99716a882]
>>>> ./perf/perf(+0x794c2) [0x55f996fed4c2]
>>>> ./perf/perf(+0x7b7c7) [0x55f996fef7c7]
>>>> ./perf/perf(+0x9074b) [0x55f99700474b]
>>>> ./perf/perf(+0x12e23c) [0x55f9970a223c]
>>>> ./perf/perf(+0x12e54a) [0x55f9970a254a]
>>>> ./perf/perf(+0x7db60) [0x55f996ff1b60]
>>>> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe6)
>>>> [0x7fa45f3b2c86]
>>>> ./perf/perf(+0x7dfe9) [0x55f996ff1fe9]
>>>> Segmentation fault (core dumped)
>>>>
>>>> backtrace of the core file is as follows:
>>>>
>>>> (gdb) bt
>>>> #0 record__bytes_written (rec=0x55f99755a200 <record>) at
>>>> builtin-record.c:234
>>>> #1 record__output_max_size_exceeded (rec=0x55f99755a200 <record>)
>>>> at builtin-record.c:242
>>>> #2 record__write (map=0x0, size=12816, bf=0x55f9978da2e0,
>>>> rec=0x55f99755a200 <record>) at builtin-record.c:263
>>>> #3 process_synthesized_event (tool=tool@entry=0x55f99755a200
>>>> <record>, event=event@entry=0x55f9978da2e0, sample=sample@entry=0x0,
>>>> machine=machine@entry=0x55f997893658) at builtin-record.c:618
>>>> #4 0x000055f99716a883 in __perf_event__synthesize_id_index
>>>> (tool=tool@entry=0x55f99755a200 <record>,
>>>> process=process@entry=0x55f997002aa0 <process_synthesized_event>,
>>>> evlist=0x55f9978928b0, machine=machine@entry=0x55f997893658,
>>>> from=from@entry=0) at util/synthetic-events.c:1895
>>>> #5 0x000055f99716a91f in perf_event__synthesize_id_index
>>>> (tool=tool@entry=0x55f99755a200 <record>,
>>>> process=process@entry=0x55f997002aa0 <process_synthesized_event>,
>>>> evlist=<optimized out>, machine=machine@entry=0x55f997893658)
>>>> at util/synthetic-events.c:1905
>>>> #6 0x000055f996fed4c3 in record__synthesize (tail=tail@entry=true,
>>>> rec=0x55f99755a200 <record>) at builtin-record.c:1997
>>>> #7 0x000055f996fef7c8 in __cmd_record (argc=argc@entry=2,
>>>> argv=argv@entry=0x7ffc67551260, rec=0x55f99755a200 <record>) at
>>>> builtin-record.c:2802
>>>> #8 0x000055f99700474c in cmd_record (argc=<optimized out>,
>>>> argv=0x7ffc67551260) at builtin-record.c:4258
>>>> #9 0x000055f9970a223d in run_builtin (p=0x55f997564d88
>>>> <commands+264>, argc=10, argv=0x7ffc67551260) at perf.c:330
>>>> #10 0x000055f9970a254b in handle_internal_command (argc=10,
>>>> argv=0x7ffc67551260) at perf.c:384
>>>> #11 0x000055f996ff1b61 in run_argv (argcp=<synthetic pointer>,
>>>> argv=<synthetic pointer>) at perf.c:428
>>>> #12 main (argc=<optimized out>, argv=0x7ffc67551260) at perf.c:562
>>>>
>>>> The reason is that record__bytes_written accesses the freed memory
>>>> rec->thread_data,
>>>> The process is as follows:
>>>> __cmd_record
>>>> -> record__free_thread_data
>>>> -> zfree(&rec->thread_data) // free rec->thread_data
>>>> -> record__synthesize
>>>> -> perf_event__synthesize_id_index
>>>> -> process_synthesized_event
>>>> -> record__write
>>>> -> record__bytes_written // access rec->thread_data
>>>>
>>>> We add a member variable "thread_bytes_written" in the struct "record"
>>>> to save the data size written by the threads.
>>>>
>>>> Fixes: 6d57581659f7 ("perf record: Add support for limit perf output
>>>> file size")
>>>> Signed-off-by: Yang Jihong <[email protected]>
>
> Acked-by: Namhyung Kim <[email protected]>
>
> Thanks,
> Namhyung
>
>
>>>> ---
>>>>
>>>> Changes since v2:
>>>> - Save data size written by threads to calculate the correct total
>>>> data size.
>>>> - Update commit message.
>>>>
>>>> Changes since v1:
>>>> - Add variable check in record__bytes_written for code hardening.
>>>> - Save bytes_written separately to reduce one calculation.
>>>> - Remove rec->opts.tail_synthesize check.
>>>>
>>>> tools/perf/builtin-record.c | 16 ++++++----------
>>>> 1 file changed, 6 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>>>> index 29dcd454b8e2..8374117e66f6 100644
>>>> --- a/tools/perf/builtin-record.c
>>>> +++ b/tools/perf/builtin-record.c
>>>> @@ -154,6 +154,7 @@ struct record {
>>>> struct perf_tool tool;
>>>> struct record_opts opts;
>>>> u64 bytes_written;
>>>> + u64 thread_bytes_written;
>>>> struct perf_data data;
>>>> struct auxtrace_record *itr;
>>>> struct evlist *evlist;
>>>> @@ -226,14 +227,7 @@ static bool switch_output_time(struct record *rec)
>>>> static u64 record__bytes_written(struct record *rec)
>>>> {
>>>> - int t;
>>>> - u64 bytes_written = rec->bytes_written;
>>>> - struct record_thread *thread_data = rec->thread_data;
>>>> -
>>>> - for (t = 0; t < rec->nr_threads; t++)
>>>> - bytes_written += thread_data[t].bytes_written;
>>>> -
>>>> - return bytes_written;
>>>> + return rec->bytes_written + rec->thread_bytes_written;
>>>> }
>>>> static bool record__output_max_size_exceeded(struct record *rec)
>>>> @@ -255,10 +249,12 @@ static int record__write(struct record *rec,
>>>> struct mmap *map __maybe_unused,
>>>> return -1;
>>>> }
>>>> - if (map && map->file)
>>>> + if (map && map->file) {
>>>> thread->bytes_written += size;
>>>> - else
>>>> + rec->thread_bytes_written += size;
>>>> + } else {
>>>> rec->bytes_written += size;
>>>> + }
>>>> if (record__output_max_size_exceeded(rec) && !done) {
>>>> fprintf(stderr, "[ perf record: perf size limit reached (%"
>>>> PRIu64 " KB),"
>>>>
>>>
>>> .
>
> .
>