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

[Sasha Levin <sashal@kernel.org>]

On Tue, Oct 08, 2019 at 07:21:25PM +0200, gregkh@linuxfoundation.org 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@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From 443f2d5ba13d65ccfd879460f77941875159d154 Mon Sep 17 00:00:00 2001
>From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
>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@linux.vnet.ibm.com>
>Acked-by: Jiri Olsa <jolsa@kernel.org>
>Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
>Tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
>Cc: Namhyung Kim <namhyung@kernel.org>
>Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
>Cc: stable@vger.kernel.org # v4.2+
>Link: http://lore.kernel.org/lkml/20190904094738.9558-3-srikar@linux.vnet.ibm.com
>Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Fixed up and queued it for 4.14-4.4.

-- 
Thanks,
Sasha