Messages in this thread | | | From | Arnaldo Carvalho de Melo <> | Date | Wed, 14 Aug 2019 15:52:13 -0300 | Subject | Re: [PATCH v3 3/4] perf: Use CAP_SYSLOG with kptr_restrict checks |
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Em Wed, Aug 14, 2019 at 03:48:14PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Wed, Aug 14, 2019 at 12:04:33PM -0600, Mathieu Poirier escreveu: > > # echo 0 > /proc/sys/kernel/kptr_restrict > > # ./tools/perf/perf record -e instructions:k uname > > perf: Segmentation fault > > Obtained 10 stack frames. > > ./tools/perf/perf(sighandler_dump_stack+0x44) [0x55af9e5da5d4] > > /lib/x86_64-linux-gnu/libc.so.6(+0x3ef20) [0x7fd31efb6f20] > > ./tools/perf/perf(perf_event__synthesize_kernel_mmap+0xa7) [0x55af9e590337] > > ./tools/perf/perf(+0x1cf5be) [0x55af9e50c5be] > > ./tools/perf/perf(cmd_record+0x1022) [0x55af9e50dff2] > > ./tools/perf/perf(+0x23f98d) [0x55af9e57c98d] > > ./tools/perf/perf(+0x23fc9e) [0x55af9e57cc9e] > > ./tools/perf/perf(main+0x369) [0x55af9e4f6bc9] > > /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7) [0x7fd31ef99b97] > > ./tools/perf/perf(_start+0x2a) [0x55af9e4f704a] > > Segmentation fault > > > > I can reproduce this on both x86 and ARM64. > > I don't see this with these two csets removed: > > 7ff5b5911144 perf symbols: Use CAP_SYSLOG with kptr_restrict checks > d7604b66102e perf tools: Use CAP_SYS_ADMIN with perf_event_paranoid checks > > Which were the ones I guessed were related to the problem you reported, > so they are out of my ongoing perf/core pull request to Ingo/Thomas, now > trying with these applied and your instructions...
Can't repro:
[root@quaco ~]# cat /proc/sys/kernel/kptr_restrict 0 [root@quaco ~]# perf record -e instructions:k uname Linux [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.024 MB perf.data (1 samples) ] [root@quaco ~]# echo 1 > /proc/sys/kernel/kptr_restrict [root@quaco ~]# perf record -e instructions:k uname Linux [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.024 MB perf.data (1 samples) ] [root@quaco ~]# echo 0 > /proc/sys/kernel/kptr_restrict [root@quaco ~]# perf record -e instructions:k uname Linux [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.024 MB perf.data (1 samples) ] [root@quaco ~]#
[acme@quaco perf]$ git log --oneline --author Lubashev tools/ 7ff5b5911144 (HEAD -> perf/cap, acme.korg/tmp.perf/cap, acme.korg/perf/cap) perf symbols: Use CAP_SYSLOG with kptr_restrict checks d7604b66102e perf tools: Use CAP_SYS_ADMIN with perf_event_paranoid checks c766f3df635d perf ftrace: Use CAP_SYS_ADMIN instead of euid==0 c22e150e3afa perf tools: Add helpers to use capabilities if present 74d5f3d06f70 tools build: Add capability-related feature detection perf version 5.3.rc4.g7ff5b5911144 [acme@quaco perf]$
- Arnaldo
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