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author | Jin Yao <yao.jin@linux.intel.com> | 2020-08-05 10:29:37 +0800 |
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committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-08-07 09:27:03 -0300 |
commit | 1101c872c8c7869c78dc106ae820040f36807eda (patch) | |
tree | a97638eefebfa98a11260c9845d5c842cd798cfd /fs/coredump.c | |
parent | 666559865823265ad2a53f72d08d42631b3dc532 (diff) | |
download | linux-1101c872c8c7869c78dc106ae820040f36807eda.tar.bz2 |
perf record: Skip side-band event setup if HAVE_LIBBPF_SUPPORT is not set
We received an error report that perf-record caused 'Segmentation fault'
on a newly system (e.g. on the new installed ubuntu).
(gdb) backtrace
#0 __read_once_size (size=4, res=<synthetic pointer>, p=0x14) at /root/0-jinyao/acme/tools/include/linux/compiler.h:139
#1 atomic_read (v=0x14) at /root/0-jinyao/acme/tools/include/asm/../../arch/x86/include/asm/atomic.h:28
#2 refcount_read (r=0x14) at /root/0-jinyao/acme/tools/include/linux/refcount.h:65
#3 perf_mmap__read_init (map=map@entry=0x0) at mmap.c:177
#4 0x0000561ce5c0de39 in perf_evlist__poll_thread (arg=0x561ce68584d0) at util/sideband_evlist.c:62
#5 0x00007fad78491609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6 0x00007fad7823c103 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
The root cause is, evlist__add_bpf_sb_event() just returns 0 if
HAVE_LIBBPF_SUPPORT is not defined (inline function path). So it will
not create a valid evsel for side-band event.
But perf-record still creates BPF side band thread to process the
side-band event, then the error happpens.
We can reproduce this issue by removing the libelf-dev. e.g.
1. apt-get remove libelf-dev
2. perf record -a -- sleep 1
root@test:~# ./perf record -a -- sleep 1
perf: Segmentation fault
Obtained 6 stack frames.
./perf(+0x28eee8) [0x5562d6ef6ee8]
/lib/x86_64-linux-gnu/libc.so.6(+0x46210) [0x7fbfdc65f210]
./perf(+0x342e74) [0x5562d6faae74]
./perf(+0x257e39) [0x5562d6ebfe39]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x9609) [0x7fbfdc990609]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x43) [0x7fbfdc73b103]
Segmentation fault (core dumped)
To fix this issue,
1. We either install the missing libraries to let HAVE_LIBBPF_SUPPORT
be defined.
e.g. apt-get install libelf-dev and install other related libraries.
2. Use this patch to skip the side-band event setup if HAVE_LIBBPF_SUPPORT
is not set.
Committer notes:
The side band thread is not used just with BPF, it is also used with
--switch-output-event, so narrow the ifdef to the BPF specific part.
Fixes: 23cbb41c939a ("perf record: Move side band evlist setup to separate routine")
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200805022937.29184-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'fs/coredump.c')
0 files changed, 0 insertions, 0 deletions