* [PATCH v2] perf record: Fix coredump with --overwrite and --max-size
@ 2022-12-29 12:47 Yang Jihong
2023-01-02 16:20 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 8+ messages in thread
From: Yang Jihong @ 2022-12-29 12:47 UTC (permalink / raw)
To: peterz, mingo, acme, mark.rutland, alexander.shishkin, jolsa,
namhyung, jiwei.sun, linux-perf-users, linux-kernel
Cc: yangjihong1
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 1M -a -- sleep 1
[ perf record: Woken up 1 times to write data ]
perf: Segmentation fault
Obtained 1 stack frames.
[0xc4c67f]
Segmentation fault (core dumped)
backtrace of the core file is as follows:
#0 0x0000000000417990 in process_locked_synthesized_event (tool=0x0, event=0x15, sample=0x1de0, machine=0xf8) at builtin-record.c:630
#1 0x000000000057ee53 in perf_event__synthesize_threads (nr_threads_synthesize=21, mmap_data=<optimized out>, needs_mmap=<optimized out>, machine=0x17ad9b0, process=<optimized out>, tool=0x0) at util/synthetic-events.c:1950
#2 __machine__synthesize_threads (nr_threads_synthesize=0, data_mmap=<optimized out>, needs_mmap=<optimized out>, process=<optimized out>, threads=0x8, target=0x8, tool=0x0, machine=0x17ad9b0) at util/synthetic-events.c:1936
#3 machine__synthesize_threads (machine=0x17ad9b0, target=0x8, threads=0x8, needs_mmap=<optimized out>, data_mmap=<optimized out>, nr_threads_synthesize=0) at util/synthetic-events.c:1947
#4 0x000000000040165d in record__synthesize (tail=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2010
#5 0x0000000000403989 in __cmd_record (argc=<optimized out>, argv=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2810
#6 0x00000000004196ba in record__init_thread_user_masks (rec=0xbe2520 <record>, cpus=0x17a65f0) at builtin-record.c:3837
#7 record__init_thread_masks (rec=0xbe2520 <record>) at builtin-record.c:3938
#8 cmd_record (argc=1, argv=0x7ffdd692dc60) at builtin-record.c:4241
#9 0x00000000004b701d in pager_command_config (var=0x0, value=0x15 <error: Cannot access memory at address 0x15>, data=0x1de0) at perf.c:117
#10 0x00000000004b732b in get_leaf_frame_caller_aarch64 (sample=0xfffffffb, thread=0x0, usr_idx=<optimized out>) at util/arm64-frame-pointer-unwind-support.c:56
#11 0x0000000000406331 in execv_dashed_external (argv=0x7ffdd692d9e8) at perf.c:410
#12 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:431
#13 main (argc=<optimized out>, argv=0x7ffdd692d9e8) 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 only need to check the value of done first.
Also add variable check in record__bytes_written for code hardening,
and save bytes_written separately to reduce one calculation.
Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
---
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 | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 29dcd454b8e2..acba9e43e519 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -230,16 +230,29 @@ static u64 record__bytes_written(struct record *rec)
u64 bytes_written = rec->bytes_written;
struct record_thread *thread_data = rec->thread_data;
+ if (thread_data == NULL)
+ return bytes_written;
+
for (t = 0; t < rec->nr_threads; t++)
bytes_written += thread_data[t].bytes_written;
return bytes_written;
}
-static bool record__output_max_size_exceeded(struct record *rec)
+static void record__check_output_max_size_exceeded(struct record *rec)
{
- return rec->output_max_size &&
- (record__bytes_written(rec) >= rec->output_max_size);
+ u64 bytes_written;
+
+ if (rec->output_max_size == 0 || done)
+ return;
+
+ bytes_written = record__bytes_written(rec);
+ if (bytes_written >= rec->output_max_size) {
+ fprintf(stderr, "[ perf record: perf size limit reached (%" PRIu64 " KB),"
+ " stopping session ]\n", bytes_written >> 10);
+
+ done = 1;
+ }
}
static int record__write(struct record *rec, struct mmap *map __maybe_unused,
@@ -260,12 +273,7 @@ static int record__write(struct record *rec, struct mmap *map __maybe_unused,
else
rec->bytes_written += size;
- if (record__output_max_size_exceeded(rec) && !done) {
- fprintf(stderr, "[ perf record: perf size limit reached (%" PRIu64 " KB),"
- " stopping session ]\n",
- record__bytes_written(rec) >> 10);
- done = 1;
- }
+ record__check_output_max_size_exceeded(rec);
if (switch_output_size(rec))
trigger_hit(&switch_output_trigger);
--
2.30.GIT
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH v2] perf record: Fix coredump with --overwrite and --max-size 2022-12-29 12:47 [PATCH v2] perf record: Fix coredump with --overwrite and --max-size Yang Jihong @ 2023-01-02 16:20 ` Arnaldo Carvalho de Melo 2023-01-03 16:50 ` Namhyung Kim 0 siblings, 1 reply; 8+ messages in thread From: Arnaldo Carvalho de Melo @ 2023-01-02 16:20 UTC (permalink / raw) To: Namhyung Kim, Yang Jihong Cc: peterz, mingo, mark.rutland, alexander.shishkin, jolsa, jiwei.sun, linux-perf-users, linux-kernel Em Thu, Dec 29, 2022 at 12:47:28PM +0000, Yang Jihong escreveu: > 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 1M -a -- sleep 1 > [ perf record: Woken up 1 times to write data ] > perf: Segmentation fault > Obtained 1 stack frames. > [0xc4c67f] > Segmentation fault (core dumped) > > backtrace of the core file is as follows: > > #0 0x0000000000417990 in process_locked_synthesized_event (tool=0x0, event=0x15, sample=0x1de0, machine=0xf8) at builtin-record.c:630 > #1 0x000000000057ee53 in perf_event__synthesize_threads (nr_threads_synthesize=21, mmap_data=<optimized out>, needs_mmap=<optimized out>, machine=0x17ad9b0, process=<optimized out>, tool=0x0) at util/synthetic-events.c:1950 > #2 __machine__synthesize_threads (nr_threads_synthesize=0, data_mmap=<optimized out>, needs_mmap=<optimized out>, process=<optimized out>, threads=0x8, target=0x8, tool=0x0, machine=0x17ad9b0) at util/synthetic-events.c:1936 > #3 machine__synthesize_threads (machine=0x17ad9b0, target=0x8, threads=0x8, needs_mmap=<optimized out>, data_mmap=<optimized out>, nr_threads_synthesize=0) at util/synthetic-events.c:1947 > #4 0x000000000040165d in record__synthesize (tail=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2010 > #5 0x0000000000403989 in __cmd_record (argc=<optimized out>, argv=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2810 > #6 0x00000000004196ba in record__init_thread_user_masks (rec=0xbe2520 <record>, cpus=0x17a65f0) at builtin-record.c:3837 > #7 record__init_thread_masks (rec=0xbe2520 <record>) at builtin-record.c:3938 > #8 cmd_record (argc=1, argv=0x7ffdd692dc60) at builtin-record.c:4241 > #9 0x00000000004b701d in pager_command_config (var=0x0, value=0x15 <error: Cannot access memory at address 0x15>, data=0x1de0) at perf.c:117 > #10 0x00000000004b732b in get_leaf_frame_caller_aarch64 (sample=0xfffffffb, thread=0x0, usr_idx=<optimized out>) at util/arm64-frame-pointer-unwind-support.c:56 > #11 0x0000000000406331 in execv_dashed_external (argv=0x7ffdd692d9e8) at perf.c:410 > #12 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:431 > #13 main (argc=<optimized out>, argv=0x7ffdd692d9e8) 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 only need to check the value of done first. > Also add variable check in record__bytes_written for code hardening, > and save bytes_written separately to reduce one calculation. > > Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size") > Signed-off-by: Yang Jihong <yangjihong1@huawei.com> > --- > > 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. Namhyung, are you ok with this now? - Arnaldo > tools/perf/builtin-record.c | 26 +++++++++++++++++--------- > 1 file changed, 17 insertions(+), 9 deletions(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 29dcd454b8e2..acba9e43e519 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -230,16 +230,29 @@ static u64 record__bytes_written(struct record *rec) > u64 bytes_written = rec->bytes_written; > struct record_thread *thread_data = rec->thread_data; > > + if (thread_data == NULL) > + return bytes_written; > + > for (t = 0; t < rec->nr_threads; t++) > bytes_written += thread_data[t].bytes_written; > > return bytes_written; > } > > -static bool record__output_max_size_exceeded(struct record *rec) > +static void record__check_output_max_size_exceeded(struct record *rec) > { > - return rec->output_max_size && > - (record__bytes_written(rec) >= rec->output_max_size); > + u64 bytes_written; > + > + if (rec->output_max_size == 0 || done) > + return; > + > + bytes_written = record__bytes_written(rec); > + if (bytes_written >= rec->output_max_size) { > + fprintf(stderr, "[ perf record: perf size limit reached (%" PRIu64 " KB)," > + " stopping session ]\n", bytes_written >> 10); > + > + done = 1; > + } > } > > static int record__write(struct record *rec, struct mmap *map __maybe_unused, > @@ -260,12 +273,7 @@ static int record__write(struct record *rec, struct mmap *map __maybe_unused, > else > rec->bytes_written += size; > > - if (record__output_max_size_exceeded(rec) && !done) { > - fprintf(stderr, "[ perf record: perf size limit reached (%" PRIu64 " KB)," > - " stopping session ]\n", > - record__bytes_written(rec) >> 10); > - done = 1; > - } > + record__check_output_max_size_exceeded(rec); > > if (switch_output_size(rec)) > trigger_hit(&switch_output_trigger); > -- > 2.30.GIT -- - Arnaldo ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] perf record: Fix coredump with --overwrite and --max-size 2023-01-02 16:20 ` Arnaldo Carvalho de Melo @ 2023-01-03 16:50 ` Namhyung Kim 2023-01-05 4:09 ` Yang Jihong 0 siblings, 1 reply; 8+ messages in thread From: Namhyung Kim @ 2023-01-03 16:50 UTC (permalink / raw) To: Arnaldo Carvalho de Melo Cc: Yang Jihong, peterz, mingo, mark.rutland, alexander.shishkin, jolsa, jiwei.sun, linux-perf-users, linux-kernel On Mon, Jan 2, 2023 at 8:20 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > > Em Thu, Dec 29, 2022 at 12:47:28PM +0000, Yang Jihong escreveu: > > 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 1M -a -- sleep 1 > > [ perf record: Woken up 1 times to write data ] > > perf: Segmentation fault > > Obtained 1 stack frames. > > [0xc4c67f] > > Segmentation fault (core dumped) > > > > backtrace of the core file is as follows: > > > > #0 0x0000000000417990 in process_locked_synthesized_event (tool=0x0, event=0x15, sample=0x1de0, machine=0xf8) at builtin-record.c:630 > > #1 0x000000000057ee53 in perf_event__synthesize_threads (nr_threads_synthesize=21, mmap_data=<optimized out>, needs_mmap=<optimized out>, machine=0x17ad9b0, process=<optimized out>, tool=0x0) at util/synthetic-events.c:1950 > > #2 __machine__synthesize_threads (nr_threads_synthesize=0, data_mmap=<optimized out>, needs_mmap=<optimized out>, process=<optimized out>, threads=0x8, target=0x8, tool=0x0, machine=0x17ad9b0) at util/synthetic-events.c:1936 > > #3 machine__synthesize_threads (machine=0x17ad9b0, target=0x8, threads=0x8, needs_mmap=<optimized out>, data_mmap=<optimized out>, nr_threads_synthesize=0) at util/synthetic-events.c:1947 > > #4 0x000000000040165d in record__synthesize (tail=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2010 > > #5 0x0000000000403989 in __cmd_record (argc=<optimized out>, argv=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2810 > > #6 0x00000000004196ba in record__init_thread_user_masks (rec=0xbe2520 <record>, cpus=0x17a65f0) at builtin-record.c:3837 > > #7 record__init_thread_masks (rec=0xbe2520 <record>) at builtin-record.c:3938 > > #8 cmd_record (argc=1, argv=0x7ffdd692dc60) at builtin-record.c:4241 > > #9 0x00000000004b701d in pager_command_config (var=0x0, value=0x15 <error: Cannot access memory at address 0x15>, data=0x1de0) at perf.c:117 > > #10 0x00000000004b732b in get_leaf_frame_caller_aarch64 (sample=0xfffffffb, thread=0x0, usr_idx=<optimized out>) at util/arm64-frame-pointer-unwind-support.c:56 > > #11 0x0000000000406331 in execv_dashed_external (argv=0x7ffdd692d9e8) at perf.c:410 > > #12 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:431 > > #13 main (argc=<optimized out>, argv=0x7ffdd692d9e8) 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 only need to check the value of done first. > > Also add variable check in record__bytes_written for code hardening, > > and save bytes_written separately to reduce one calculation. > > > > Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size") > > Signed-off-by: Yang Jihong <yangjihong1@huawei.com> > > --- > > > > 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. > > Namhyung, are you ok with this now? > > - Arnaldo > > > tools/perf/builtin-record.c | 26 +++++++++++++++++--------- > > 1 file changed, 17 insertions(+), 9 deletions(-) > > > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > > index 29dcd454b8e2..acba9e43e519 100644 > > --- a/tools/perf/builtin-record.c > > +++ b/tools/perf/builtin-record.c > > @@ -230,16 +230,29 @@ static u64 record__bytes_written(struct record *rec) > > u64 bytes_written = rec->bytes_written; > > struct record_thread *thread_data = rec->thread_data; > > > > + if (thread_data == NULL) > > + return bytes_written; > > + Then it won't count bytes written by threads, right? I think it needs to be saved somewhere. Thanks, Namhyung > > for (t = 0; t < rec->nr_threads; t++) > > bytes_written += thread_data[t].bytes_written; > > > > return bytes_written; > > } > > > > -static bool record__output_max_size_exceeded(struct record *rec) > > +static void record__check_output_max_size_exceeded(struct record *rec) > > { > > - return rec->output_max_size && > > - (record__bytes_written(rec) >= rec->output_max_size); > > + u64 bytes_written; > > + > > + if (rec->output_max_size == 0 || done) > > + return; > > + > > + bytes_written = record__bytes_written(rec); > > + if (bytes_written >= rec->output_max_size) { > > + fprintf(stderr, "[ perf record: perf size limit reached (%" PRIu64 " KB)," > > + " stopping session ]\n", bytes_written >> 10); > > + > > + done = 1; > > + } > > } > > > > static int record__write(struct record *rec, struct mmap *map __maybe_unused, > > @@ -260,12 +273,7 @@ static int record__write(struct record *rec, struct mmap *map __maybe_unused, > > else > > rec->bytes_written += size; > > > > - if (record__output_max_size_exceeded(rec) && !done) { > > - fprintf(stderr, "[ perf record: perf size limit reached (%" PRIu64 " KB)," > > - " stopping session ]\n", > > - record__bytes_written(rec) >> 10); > > - done = 1; > > - } > > + record__check_output_max_size_exceeded(rec); > > > > if (switch_output_size(rec)) > > trigger_hit(&switch_output_trigger); > > -- > > 2.30.GIT > > -- > > - Arnaldo ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] perf record: Fix coredump with --overwrite and --max-size 2023-01-03 16:50 ` Namhyung Kim @ 2023-01-05 4:09 ` Yang Jihong 2023-01-06 21:12 ` Namhyung Kim 0 siblings, 1 reply; 8+ messages in thread From: Yang Jihong @ 2023-01-05 4:09 UTC (permalink / raw) To: Namhyung Kim, Arnaldo Carvalho de Melo Cc: peterz, mingo, mark.rutland, alexander.shishkin, jolsa, jiwei.sun, linux-perf-users, linux-kernel Hello, On 2023/1/4 0:50, Namhyung Kim wrote: > On Mon, Jan 2, 2023 at 8:20 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote: >> >> Em Thu, Dec 29, 2022 at 12:47:28PM +0000, Yang Jihong escreveu: >>> 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 1M -a -- sleep 1 >>> [ perf record: Woken up 1 times to write data ] >>> perf: Segmentation fault >>> Obtained 1 stack frames. >>> [0xc4c67f] >>> Segmentation fault (core dumped) >>> >>> backtrace of the core file is as follows: >>> >>> #0 0x0000000000417990 in process_locked_synthesized_event (tool=0x0, event=0x15, sample=0x1de0, machine=0xf8) at builtin-record.c:630 >>> #1 0x000000000057ee53 in perf_event__synthesize_threads (nr_threads_synthesize=21, mmap_data=<optimized out>, needs_mmap=<optimized out>, machine=0x17ad9b0, process=<optimized out>, tool=0x0) at util/synthetic-events.c:1950 >>> #2 __machine__synthesize_threads (nr_threads_synthesize=0, data_mmap=<optimized out>, needs_mmap=<optimized out>, process=<optimized out>, threads=0x8, target=0x8, tool=0x0, machine=0x17ad9b0) at util/synthetic-events.c:1936 >>> #3 machine__synthesize_threads (machine=0x17ad9b0, target=0x8, threads=0x8, needs_mmap=<optimized out>, data_mmap=<optimized out>, nr_threads_synthesize=0) at util/synthetic-events.c:1947 >>> #4 0x000000000040165d in record__synthesize (tail=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2010 >>> #5 0x0000000000403989 in __cmd_record (argc=<optimized out>, argv=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2810 >>> #6 0x00000000004196ba in record__init_thread_user_masks (rec=0xbe2520 <record>, cpus=0x17a65f0) at builtin-record.c:3837 >>> #7 record__init_thread_masks (rec=0xbe2520 <record>) at builtin-record.c:3938 >>> #8 cmd_record (argc=1, argv=0x7ffdd692dc60) at builtin-record.c:4241 >>> #9 0x00000000004b701d in pager_command_config (var=0x0, value=0x15 <error: Cannot access memory at address 0x15>, data=0x1de0) at perf.c:117 >>> #10 0x00000000004b732b in get_leaf_frame_caller_aarch64 (sample=0xfffffffb, thread=0x0, usr_idx=<optimized out>) at util/arm64-frame-pointer-unwind-support.c:56 >>> #11 0x0000000000406331 in execv_dashed_external (argv=0x7ffdd692d9e8) at perf.c:410 >>> #12 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:431 >>> #13 main (argc=<optimized out>, argv=0x7ffdd692d9e8) 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 only need to check the value of done first. >>> Also add variable check in record__bytes_written for code hardening, >>> and save bytes_written separately to reduce one calculation. >>> >>> Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size") >>> Signed-off-by: Yang Jihong <yangjihong1@huawei.com> >>> --- >>> >>> 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. >> >> Namhyung, are you ok with this now? >> >> - Arnaldo >> >>> tools/perf/builtin-record.c | 26 +++++++++++++++++--------- >>> 1 file changed, 17 insertions(+), 9 deletions(-) >>> >>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c >>> index 29dcd454b8e2..acba9e43e519 100644 >>> --- a/tools/perf/builtin-record.c >>> +++ b/tools/perf/builtin-record.c >>> @@ -230,16 +230,29 @@ static u64 record__bytes_written(struct record *rec) >>> u64 bytes_written = rec->bytes_written; >>> struct record_thread *thread_data = rec->thread_data; >>> >>> + if (thread_data == NULL) >>> + return bytes_written; >>> + > > Then it won't count bytes written by threads, right? > I think it needs to be saved somewhere. > I'm not sure here. Can you explain it more clearly, thanks :) I can modify it accordingly. I think if thread_data == NULL, it is not thread data. In this case, we just return rec->bytes_written. Thanks, Yang ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] perf record: Fix coredump with --overwrite and --max-size 2023-01-05 4:09 ` Yang Jihong @ 2023-01-06 21:12 ` Namhyung Kim 2023-01-09 2:46 ` Yang Jihong 0 siblings, 1 reply; 8+ messages in thread From: Namhyung Kim @ 2023-01-06 21:12 UTC (permalink / raw) To: Yang Jihong Cc: Arnaldo Carvalho de Melo, peterz, mingo, mark.rutland, alexander.shishkin, jolsa, jiwei.sun, linux-perf-users, linux-kernel Hello, On Wed, Jan 4, 2023 at 8:09 PM Yang Jihong <yangjihong1@huawei.com> wrote: > > Hello, > > On 2023/1/4 0:50, Namhyung Kim wrote: > > On Mon, Jan 2, 2023 at 8:20 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > >> > >> Em Thu, Dec 29, 2022 at 12:47:28PM +0000, Yang Jihong escreveu: > >>> 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 1M -a -- sleep 1 > >>> [ perf record: Woken up 1 times to write data ] > >>> perf: Segmentation fault > >>> Obtained 1 stack frames. > >>> [0xc4c67f] > >>> Segmentation fault (core dumped) > >>> > >>> backtrace of the core file is as follows: > >>> > >>> #0 0x0000000000417990 in process_locked_synthesized_event (tool=0x0, event=0x15, sample=0x1de0, machine=0xf8) at builtin-record.c:630 > >>> #1 0x000000000057ee53 in perf_event__synthesize_threads (nr_threads_synthesize=21, mmap_data=<optimized out>, needs_mmap=<optimized out>, machine=0x17ad9b0, process=<optimized out>, tool=0x0) at util/synthetic-events.c:1950 > >>> #2 __machine__synthesize_threads (nr_threads_synthesize=0, data_mmap=<optimized out>, needs_mmap=<optimized out>, process=<optimized out>, threads=0x8, target=0x8, tool=0x0, machine=0x17ad9b0) at util/synthetic-events.c:1936 > >>> #3 machine__synthesize_threads (machine=0x17ad9b0, target=0x8, threads=0x8, needs_mmap=<optimized out>, data_mmap=<optimized out>, nr_threads_synthesize=0) at util/synthetic-events.c:1947 > >>> #4 0x000000000040165d in record__synthesize (tail=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2010 > >>> #5 0x0000000000403989 in __cmd_record (argc=<optimized out>, argv=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2810 > >>> #6 0x00000000004196ba in record__init_thread_user_masks (rec=0xbe2520 <record>, cpus=0x17a65f0) at builtin-record.c:3837 > >>> #7 record__init_thread_masks (rec=0xbe2520 <record>) at builtin-record.c:3938 > >>> #8 cmd_record (argc=1, argv=0x7ffdd692dc60) at builtin-record.c:4241 > >>> #9 0x00000000004b701d in pager_command_config (var=0x0, value=0x15 <error: Cannot access memory at address 0x15>, data=0x1de0) at perf.c:117 > >>> #10 0x00000000004b732b in get_leaf_frame_caller_aarch64 (sample=0xfffffffb, thread=0x0, usr_idx=<optimized out>) at util/arm64-frame-pointer-unwind-support.c:56 > >>> #11 0x0000000000406331 in execv_dashed_external (argv=0x7ffdd692d9e8) at perf.c:410 > >>> #12 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:431 > >>> #13 main (argc=<optimized out>, argv=0x7ffdd692d9e8) 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 only need to check the value of done first. > >>> Also add variable check in record__bytes_written for code hardening, > >>> and save bytes_written separately to reduce one calculation. > >>> > >>> Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size") > >>> Signed-off-by: Yang Jihong <yangjihong1@huawei.com> > >>> --- > >>> > >>> 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. > >> > >> Namhyung, are you ok with this now? > >> > >> - Arnaldo > >> > >>> tools/perf/builtin-record.c | 26 +++++++++++++++++--------- > >>> 1 file changed, 17 insertions(+), 9 deletions(-) > >>> > >>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > >>> index 29dcd454b8e2..acba9e43e519 100644 > >>> --- a/tools/perf/builtin-record.c > >>> +++ b/tools/perf/builtin-record.c > >>> @@ -230,16 +230,29 @@ static u64 record__bytes_written(struct record *rec) > >>> u64 bytes_written = rec->bytes_written; > >>> struct record_thread *thread_data = rec->thread_data; > >>> > >>> + if (thread_data == NULL) > >>> + return bytes_written; > >>> + > > > > Then it won't count bytes written by threads, right? > > I think it needs to be saved somewhere. > > > I'm not sure here. Can you explain it more clearly, thanks :) > I can modify it accordingly. > > I think if thread_data == NULL, it is not thread data. > In this case, we just return rec->bytes_written. It can be thread data but freed before tail synthesis, right? In that case, I think it needs to add bytes_written by threads to calculate the correct data size. Thanks, Namhyung ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] perf record: Fix coredump with --overwrite and --max-size 2023-01-06 21:12 ` Namhyung Kim @ 2023-01-09 2:46 ` Yang Jihong 2023-01-10 19:21 ` Namhyung Kim 0 siblings, 1 reply; 8+ messages in thread From: Yang Jihong @ 2023-01-09 2:46 UTC (permalink / raw) To: Namhyung Kim Cc: Arnaldo Carvalho de Melo, peterz, mingo, mark.rutland, alexander.shishkin, jolsa, jiwei.sun, linux-perf-users, linux-kernel Hello, On 2023/1/7 5:12, Namhyung Kim wrote: > Hello, > > On Wed, Jan 4, 2023 at 8:09 PM Yang Jihong <yangjihong1@huawei.com> wrote: >> >> Hello, >> >> On 2023/1/4 0:50, Namhyung Kim wrote: >>> On Mon, Jan 2, 2023 at 8:20 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote: >>>> >>>> Em Thu, Dec 29, 2022 at 12:47:28PM +0000, Yang Jihong escreveu: >>>>> 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 1M -a -- sleep 1 >>>>> [ perf record: Woken up 1 times to write data ] >>>>> perf: Segmentation fault >>>>> Obtained 1 stack frames. >>>>> [0xc4c67f] >>>>> Segmentation fault (core dumped) >>>>> >>>>> backtrace of the core file is as follows: >>>>> >>>>> #0 0x0000000000417990 in process_locked_synthesized_event (tool=0x0, event=0x15, sample=0x1de0, machine=0xf8) at builtin-record.c:630 >>>>> #1 0x000000000057ee53 in perf_event__synthesize_threads (nr_threads_synthesize=21, mmap_data=<optimized out>, needs_mmap=<optimized out>, machine=0x17ad9b0, process=<optimized out>, tool=0x0) at util/synthetic-events.c:1950 >>>>> #2 __machine__synthesize_threads (nr_threads_synthesize=0, data_mmap=<optimized out>, needs_mmap=<optimized out>, process=<optimized out>, threads=0x8, target=0x8, tool=0x0, machine=0x17ad9b0) at util/synthetic-events.c:1936 >>>>> #3 machine__synthesize_threads (machine=0x17ad9b0, target=0x8, threads=0x8, needs_mmap=<optimized out>, data_mmap=<optimized out>, nr_threads_synthesize=0) at util/synthetic-events.c:1947 >>>>> #4 0x000000000040165d in record__synthesize (tail=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2010 >>>>> #5 0x0000000000403989 in __cmd_record (argc=<optimized out>, argv=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2810 >>>>> #6 0x00000000004196ba in record__init_thread_user_masks (rec=0xbe2520 <record>, cpus=0x17a65f0) at builtin-record.c:3837 >>>>> #7 record__init_thread_masks (rec=0xbe2520 <record>) at builtin-record.c:3938 >>>>> #8 cmd_record (argc=1, argv=0x7ffdd692dc60) at builtin-record.c:4241 >>>>> #9 0x00000000004b701d in pager_command_config (var=0x0, value=0x15 <error: Cannot access memory at address 0x15>, data=0x1de0) at perf.c:117 >>>>> #10 0x00000000004b732b in get_leaf_frame_caller_aarch64 (sample=0xfffffffb, thread=0x0, usr_idx=<optimized out>) at util/arm64-frame-pointer-unwind-support.c:56 >>>>> #11 0x0000000000406331 in execv_dashed_external (argv=0x7ffdd692d9e8) at perf.c:410 >>>>> #12 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:431 >>>>> #13 main (argc=<optimized out>, argv=0x7ffdd692d9e8) 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 only need to check the value of done first. >>>>> Also add variable check in record__bytes_written for code hardening, >>>>> and save bytes_written separately to reduce one calculation. >>>>> >>>>> Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size") >>>>> Signed-off-by: Yang Jihong <yangjihong1@huawei.com> >>>>> --- >>>>> >>>>> 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. >>>> >>>> Namhyung, are you ok with this now? >>>> >>>> - Arnaldo >>>> >>>>> tools/perf/builtin-record.c | 26 +++++++++++++++++--------- >>>>> 1 file changed, 17 insertions(+), 9 deletions(-) >>>>> >>>>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c >>>>> index 29dcd454b8e2..acba9e43e519 100644 >>>>> --- a/tools/perf/builtin-record.c >>>>> +++ b/tools/perf/builtin-record.c >>>>> @@ -230,16 +230,29 @@ static u64 record__bytes_written(struct record *rec) >>>>> u64 bytes_written = rec->bytes_written; >>>>> struct record_thread *thread_data = rec->thread_data; >>>>> >>>>> + if (thread_data == NULL) >>>>> + return bytes_written; >>>>> + >>> >>> Then it won't count bytes written by threads, right? >>> I think it needs to be saved somewhere. >>> >> I'm not sure here. Can you explain it more clearly, thanks :) >> I can modify it accordingly. >> >> I think if thread_data == NULL, it is not thread data. >> In this case, we just return rec->bytes_written. > > It can be thread data but freed before tail synthesis, right? > In that case, I think it needs to add bytes_written by threads > to calculate the correct data size. Em... In the __cmd_record function, record__stop_threads is called before record__free_thread_data, so if the thread has been freed, there will be no thread data. I think it's okay to ignore the situation you mentioned above. Thanks, Yang ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] perf record: Fix coredump with --overwrite and --max-size 2023-01-09 2:46 ` Yang Jihong @ 2023-01-10 19:21 ` Namhyung Kim 2023-01-13 6:53 ` Yang Jihong 0 siblings, 1 reply; 8+ messages in thread From: Namhyung Kim @ 2023-01-10 19:21 UTC (permalink / raw) To: Yang Jihong Cc: Arnaldo Carvalho de Melo, peterz, mingo, mark.rutland, alexander.shishkin, jolsa, jiwei.sun, linux-perf-users, linux-kernel On Sun, Jan 8, 2023 at 6:47 PM Yang Jihong <yangjihong1@huawei.com> wrote: > > Hello, > > On 2023/1/7 5:12, Namhyung Kim wrote: > > Hello, > > > > On Wed, Jan 4, 2023 at 8:09 PM Yang Jihong <yangjihong1@huawei.com> wrote: > >> > >> Hello, > >> > >> On 2023/1/4 0:50, Namhyung Kim wrote: > >>> On Mon, Jan 2, 2023 at 8:20 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > >>>> > >>>> Em Thu, Dec 29, 2022 at 12:47:28PM +0000, Yang Jihong escreveu: > >>>>> 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 1M -a -- sleep 1 > >>>>> [ perf record: Woken up 1 times to write data ] > >>>>> perf: Segmentation fault > >>>>> Obtained 1 stack frames. > >>>>> [0xc4c67f] > >>>>> Segmentation fault (core dumped) > >>>>> > >>>>> backtrace of the core file is as follows: > >>>>> > >>>>> #0 0x0000000000417990 in process_locked_synthesized_event (tool=0x0, event=0x15, sample=0x1de0, machine=0xf8) at builtin-record.c:630 > >>>>> #1 0x000000000057ee53 in perf_event__synthesize_threads (nr_threads_synthesize=21, mmap_data=<optimized out>, needs_mmap=<optimized out>, machine=0x17ad9b0, process=<optimized out>, tool=0x0) at util/synthetic-events.c:1950 > >>>>> #2 __machine__synthesize_threads (nr_threads_synthesize=0, data_mmap=<optimized out>, needs_mmap=<optimized out>, process=<optimized out>, threads=0x8, target=0x8, tool=0x0, machine=0x17ad9b0) at util/synthetic-events.c:1936 > >>>>> #3 machine__synthesize_threads (machine=0x17ad9b0, target=0x8, threads=0x8, needs_mmap=<optimized out>, data_mmap=<optimized out>, nr_threads_synthesize=0) at util/synthetic-events.c:1947 > >>>>> #4 0x000000000040165d in record__synthesize (tail=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2010 > >>>>> #5 0x0000000000403989 in __cmd_record (argc=<optimized out>, argv=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2810 > >>>>> #6 0x00000000004196ba in record__init_thread_user_masks (rec=0xbe2520 <record>, cpus=0x17a65f0) at builtin-record.c:3837 > >>>>> #7 record__init_thread_masks (rec=0xbe2520 <record>) at builtin-record.c:3938 > >>>>> #8 cmd_record (argc=1, argv=0x7ffdd692dc60) at builtin-record.c:4241 > >>>>> #9 0x00000000004b701d in pager_command_config (var=0x0, value=0x15 <error: Cannot access memory at address 0x15>, data=0x1de0) at perf.c:117 > >>>>> #10 0x00000000004b732b in get_leaf_frame_caller_aarch64 (sample=0xfffffffb, thread=0x0, usr_idx=<optimized out>) at util/arm64-frame-pointer-unwind-support.c:56 > >>>>> #11 0x0000000000406331 in execv_dashed_external (argv=0x7ffdd692d9e8) at perf.c:410 > >>>>> #12 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:431 > >>>>> #13 main (argc=<optimized out>, argv=0x7ffdd692d9e8) 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 only need to check the value of done first. > >>>>> Also add variable check in record__bytes_written for code hardening, > >>>>> and save bytes_written separately to reduce one calculation. > >>>>> > >>>>> Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size") > >>>>> Signed-off-by: Yang Jihong <yangjihong1@huawei.com> > >>>>> --- > >>>>> > >>>>> 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. > >>>> > >>>> Namhyung, are you ok with this now? > >>>> > >>>> - Arnaldo > >>>> > >>>>> tools/perf/builtin-record.c | 26 +++++++++++++++++--------- > >>>>> 1 file changed, 17 insertions(+), 9 deletions(-) > >>>>> > >>>>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > >>>>> index 29dcd454b8e2..acba9e43e519 100644 > >>>>> --- a/tools/perf/builtin-record.c > >>>>> +++ b/tools/perf/builtin-record.c > >>>>> @@ -230,16 +230,29 @@ static u64 record__bytes_written(struct record *rec) > >>>>> u64 bytes_written = rec->bytes_written; > >>>>> struct record_thread *thread_data = rec->thread_data; > >>>>> > >>>>> + if (thread_data == NULL) > >>>>> + return bytes_written; > >>>>> + > >>> > >>> Then it won't count bytes written by threads, right? > >>> I think it needs to be saved somewhere. > >>> > >> I'm not sure here. Can you explain it more clearly, thanks :) > >> I can modify it accordingly. > >> > >> I think if thread_data == NULL, it is not thread data. > >> In this case, we just return rec->bytes_written. > > > > It can be thread data but freed before tail synthesis, right? > > In that case, I think it needs to add bytes_written by threads > > to calculate the correct data size. > Em... In the __cmd_record function, record__stop_threads is called > before record__free_thread_data, so if the thread has been freed, there > will be no thread data. > I think it's okay to ignore the situation you mentioned above. Right, the thread data is already freed, but we need the size. I think it didn't (and won't) update to rec->bytes_written for the data written by the threads (data.X file) because it's only for the main 'data' file. So record__bytes_written() will return a smaller number after the threads are gone. But I think it should return the total data size. Thanks, Namhyung ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] perf record: Fix coredump with --overwrite and --max-size 2023-01-10 19:21 ` Namhyung Kim @ 2023-01-13 6:53 ` Yang Jihong 0 siblings, 0 replies; 8+ messages in thread From: Yang Jihong @ 2023-01-13 6:53 UTC (permalink / raw) To: Namhyung Kim Cc: Arnaldo Carvalho de Melo, peterz, mingo, mark.rutland, alexander.shishkin, jolsa, jiwei.sun, linux-perf-users, linux-kernel Hello, On 2023/1/11 3:21, Namhyung Kim wrote: > On Sun, Jan 8, 2023 at 6:47 PM Yang Jihong <yangjihong1@huawei.com> wrote: >> >> Hello, >> >> On 2023/1/7 5:12, Namhyung Kim wrote: >>> Hello, >>> >>> On Wed, Jan 4, 2023 at 8:09 PM Yang Jihong <yangjihong1@huawei.com> wrote: >>>> >>>> Hello, >>>> >>>> On 2023/1/4 0:50, Namhyung Kim wrote: >>>>> On Mon, Jan 2, 2023 at 8:20 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote: >>>>>> >>>>>> Em Thu, Dec 29, 2022 at 12:47:28PM +0000, Yang Jihong escreveu: >>>>>>> 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 1M -a -- sleep 1 >>>>>>> [ perf record: Woken up 1 times to write data ] >>>>>>> perf: Segmentation fault >>>>>>> Obtained 1 stack frames. >>>>>>> [0xc4c67f] >>>>>>> Segmentation fault (core dumped) >>>>>>> >>>>>>> backtrace of the core file is as follows: >>>>>>> >>>>>>> #0 0x0000000000417990 in process_locked_synthesized_event (tool=0x0, event=0x15, sample=0x1de0, machine=0xf8) at builtin-record.c:630 >>>>>>> #1 0x000000000057ee53 in perf_event__synthesize_threads (nr_threads_synthesize=21, mmap_data=<optimized out>, needs_mmap=<optimized out>, machine=0x17ad9b0, process=<optimized out>, tool=0x0) at util/synthetic-events.c:1950 >>>>>>> #2 __machine__synthesize_threads (nr_threads_synthesize=0, data_mmap=<optimized out>, needs_mmap=<optimized out>, process=<optimized out>, threads=0x8, target=0x8, tool=0x0, machine=0x17ad9b0) at util/synthetic-events.c:1936 >>>>>>> #3 machine__synthesize_threads (machine=0x17ad9b0, target=0x8, threads=0x8, needs_mmap=<optimized out>, data_mmap=<optimized out>, nr_threads_synthesize=0) at util/synthetic-events.c:1947 >>>>>>> #4 0x000000000040165d in record__synthesize (tail=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2010 >>>>>>> #5 0x0000000000403989 in __cmd_record (argc=<optimized out>, argv=<optimized out>, rec=0xbe2520 <record>) at builtin-record.c:2810 >>>>>>> #6 0x00000000004196ba in record__init_thread_user_masks (rec=0xbe2520 <record>, cpus=0x17a65f0) at builtin-record.c:3837 >>>>>>> #7 record__init_thread_masks (rec=0xbe2520 <record>) at builtin-record.c:3938 >>>>>>> #8 cmd_record (argc=1, argv=0x7ffdd692dc60) at builtin-record.c:4241 >>>>>>> #9 0x00000000004b701d in pager_command_config (var=0x0, value=0x15 <error: Cannot access memory at address 0x15>, data=0x1de0) at perf.c:117 >>>>>>> #10 0x00000000004b732b in get_leaf_frame_caller_aarch64 (sample=0xfffffffb, thread=0x0, usr_idx=<optimized out>) at util/arm64-frame-pointer-unwind-support.c:56 >>>>>>> #11 0x0000000000406331 in execv_dashed_external (argv=0x7ffdd692d9e8) at perf.c:410 >>>>>>> #12 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:431 >>>>>>> #13 main (argc=<optimized out>, argv=0x7ffdd692d9e8) 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 only need to check the value of done first. >>>>>>> Also add variable check in record__bytes_written for code hardening, >>>>>>> and save bytes_written separately to reduce one calculation. >>>>>>> >>>>>>> Fixes: 6d57581659f7 ("perf record: Add support for limit perf output file size") >>>>>>> Signed-off-by: Yang Jihong <yangjihong1@huawei.com> >>>>>>> --- >>>>>>> >>>>>>> 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. >>>>>> >>>>>> Namhyung, are you ok with this now? >>>>>> >>>>>> - Arnaldo >>>>>> >>>>>>> tools/perf/builtin-record.c | 26 +++++++++++++++++--------- >>>>>>> 1 file changed, 17 insertions(+), 9 deletions(-) >>>>>>> >>>>>>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c >>>>>>> index 29dcd454b8e2..acba9e43e519 100644 >>>>>>> --- a/tools/perf/builtin-record.c >>>>>>> +++ b/tools/perf/builtin-record.c >>>>>>> @@ -230,16 +230,29 @@ static u64 record__bytes_written(struct record *rec) >>>>>>> u64 bytes_written = rec->bytes_written; >>>>>>> struct record_thread *thread_data = rec->thread_data; >>>>>>> >>>>>>> + if (thread_data == NULL) >>>>>>> + return bytes_written; >>>>>>> + >>>>> >>>>> Then it won't count bytes written by threads, right? >>>>> I think it needs to be saved somewhere. >>>>> >>>> I'm not sure here. Can you explain it more clearly, thanks :) >>>> I can modify it accordingly. >>>> >>>> I think if thread_data == NULL, it is not thread data. >>>> In this case, we just return rec->bytes_written. >>> >>> It can be thread data but freed before tail synthesis, right? >>> In that case, I think it needs to add bytes_written by threads >>> to calculate the correct data size. >> Em... In the __cmd_record function, record__stop_threads is called >> before record__free_thread_data, so if the thread has been freed, there >> will be no thread data. >> I think it's okay to ignore the situation you mentioned above. > > Right, the thread data is already freed, but we need the size. > > I think it didn't (and won't) update to rec->bytes_written for the data > written by the threads (data.X file) because it's only for the main > 'data' file. So record__bytes_written() will return a smaller number > after the threads are gone. But I think it should return the total > data size. > Yes, the total data size including data.X file should be returned here to fit the semantics, so there's a problem here, too. will fix in next version. Thanks, Yang ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2023-01-13 7:05 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-12-29 12:47 [PATCH v2] perf record: Fix coredump with --overwrite and --max-size Yang Jihong 2023-01-02 16:20 ` Arnaldo Carvalho de Melo 2023-01-03 16:50 ` Namhyung Kim 2023-01-05 4:09 ` Yang Jihong 2023-01-06 21:12 ` Namhyung Kim 2023-01-09 2:46 ` Yang Jihong 2023-01-10 19:21 ` Namhyung Kim 2023-01-13 6:53 ` Yang Jihong
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