Re: FAILED: patch "[PATCH] perf stat: Fix a segmentation fault when using repeat forever" failed to apply to 4.14-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, Oct 08, 2019 at 07:21:25PM +0200, gregkh@xxxxxxxxxxxxxxxxxxx wrote:

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 443f2d5ba13d65ccfd879460f77941875159d154 Mon Sep 17 00:00:00 2001
From: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Date: Wed, 4 Sep 2019 15:17:38 +0530
Subject: [PATCH] perf stat: Fix a segmentation fault when using repeat forever

Observe a segmentation fault when 'perf stat' is asked to repeat forever
with the interval option.

Without fix:

 # perf stat -r 0 -I 5000 -e cycles -a sleep 10
 #           time             counts unit events
      5.000211692  3,13,89,82,34,157      cycles
     10.000380119  1,53,98,52,22,294      cycles
     10.040467280       17,16,79,265      cycles
 Segmentation fault

This problem was only observed when we use forever option aka -r 0 and
works with limited repeats. Calling print_counter with ts being set to
NULL, is not a correct option when interval is set. Hence avoid
print_counter(NULL,..)  if interval is set.

With fix:

 # perf stat -r 0 -I 5000 -e cycles -a sleep 10
  #           time             counts unit events
      5.019866622  3,15,14,43,08,697      cycles
     10.039865756  3,15,16,31,95,261      cycles
     10.059950628     1,26,05,47,158      cycles
      5.009902655  3,14,52,62,33,932      cycles
     10.019880228  3,14,52,22,89,154      cycles
     10.030543876       66,90,18,333      cycles
      5.009848281  3,14,51,98,25,437      cycles
     10.029854402  3,15,14,93,04,918      cycles
      5.009834177  3,14,51,95,92,316      cycles

Committer notes:

Did the 'git bisect' to find the cset introducing the problem to add the
Fixes tag below, and at that time the problem reproduced as:

 (gdb) run stat -r0 -I500 sleep 1
 <SNIP>
 Program received signal SIGSEGV, Segmentation fault.
 print_interval (prefix=prefix@entry=0x7fffffffc8d0 "", ts=ts@entry=0x0) at builtin-stat.c:866
 866		sprintf(prefix, "%6lu.%09lu%s", ts->tv_sec, ts->tv_nsec, csv_sep);
 (gdb) bt
 #0  print_interval (prefix=prefix@entry=0x7fffffffc8d0 "", ts=ts@entry=0x0) at builtin-stat.c:866
 #1  0x000000000041860a in print_counters (ts=ts@entry=0x0, argc=argc@entry=2, argv=argv@entry=0x7fffffffd640) at builtin-stat.c:938
 #2  0x0000000000419a7f in cmd_stat (argc=2, argv=0x7fffffffd640, prefix=<optimized out>) at builtin-stat.c:1411
 #3  0x000000000045c65a in run_builtin (p=p@entry=0x6291b8 <commands+216>, argc=argc@entry=5, argv=argv@entry=0x7fffffffd640) at perf.c:370
 #4  0x000000000045c893 in handle_internal_command (argc=5, argv=0x7fffffffd640) at perf.c:429
 #5  0x000000000045c8f1 in run_argv (argcp=argcp@entry=0x7fffffffd4ac, argv=argv@entry=0x7fffffffd4a0) at perf.c:473
 #6  0x000000000045cac9 in main (argc=<optimized out>, argv=<optimized out>) at perf.c:588
 (gdb)

Mostly the same as just before this patch:

 Program received signal SIGSEGV, Segmentation fault.
 0x00000000005874a7 in print_interval (config=0xa1f2a0 <stat_config>, evlist=0xbc9b90, prefix=0x7fffffffd1c0 "`", ts=0x0) at util/stat-display.c:964
 964		sprintf(prefix, "%6lu.%09lu%s", ts->tv_sec, ts->tv_nsec, config->csv_sep);
 (gdb) bt
 #0  0x00000000005874a7 in print_interval (config=0xa1f2a0 <stat_config>, evlist=0xbc9b90, prefix=0x7fffffffd1c0 "`", ts=0x0) at util/stat-display.c:964
 #1  0x0000000000588047 in perf_evlist__print_counters (evlist=0xbc9b90, config=0xa1f2a0 <stat_config>, _target=0xa1f0c0 <target>, ts=0x0, argc=2, argv=0x7fffffffd670)
     at util/stat-display.c:1172
 #2  0x000000000045390f in print_counters (ts=0x0, argc=2, argv=0x7fffffffd670) at builtin-stat.c:656
 #3  0x0000000000456bb5 in cmd_stat (argc=2, argv=0x7fffffffd670) at builtin-stat.c:1960
 #4  0x00000000004dd2e0 in run_builtin (p=0xa30e00 <commands+288>, argc=5, argv=0x7fffffffd670) at perf.c:310
 #5  0x00000000004dd54d in handle_internal_command (argc=5, argv=0x7fffffffd670) at perf.c:362
 #6  0x00000000004dd694 in run_argv (argcp=0x7fffffffd4cc, argv=0x7fffffffd4c0) at perf.c:406
 #7  0x00000000004dda11 in main (argc=5, argv=0x7fffffffd670) at perf.c:531
 (gdb)

Fixes: d4f63a4741a8 ("perf stat: Introduce print_counters function")
Signed-off-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Tested-by: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v4.2+
Link: http://lore.kernel.org/lkml/20190904094738.9558-3-srikar@xxxxxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Fixed up and queued it for 4.14-4.4.

--
Thanks,
Sasha



[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux