diff options
author | Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> | 2017-07-19 02:20:19 +0300 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2017-07-25 17:23:50 +0300 |
commit | cd8dd032f61abeb08d2c03bab4968a9de231a1be (patch) | |
tree | fa2b0160a386902d9e827ac8deafdc5a3786df7c /tools/perf/util/cgroup.c | |
parent | cf6383f73cf2be45d566fdb2b15b799675669de0 (diff) | |
download | linux-cd8dd032f61abeb08d2c03bab4968a9de231a1be.tar.xz |
perf cgroup: Fix refcount usage
When converting from atomic_t to refcount_t we didn't follow the usual
step of initializing it to one before taking any new reference, which
trips over checking if taking a reference for a freed refcount_t, fix
it.
Brendan's report:
---
It's 4.12-rc7, with node v4.4.1. I'm building 4.13-rc1 now, as I hit
what I think is another unrelated perf bug and I'm starting to wonder
what else is broken on that version:
(root) /mnt/src/linux-4.12-rc7/tools/perf # ./perf record -F 99 -a -e
cpu-clock --cgroup=docker/f9e9d5df065b14646e8a11edc837a13877fd90c171137b2ba3feb67a0201cb65
-g
perf: /mnt/src/linux-4.12-rc7/tools/include/linux/refcount.h:108:
refcount_inc: Assertion `!(!refcount_inc_not_zero(r))' failed.
Aborted
that used to work...
---
Testing it:
Before:
# perf stat -e cycles -C 0 --cgroup /
perf: /home/acme/git/linux/tools/include/linux/refcount.h:108: refcount_inc: Assertion `!(!refcount_inc_not_zero(r))' failed.
Aborted (core dumped)
#
After:
# perf stat -e cycles -C 0 --cgroup /
^C
Performance counter stats for 'CPU(s) 0':
132,081,393 cycles /
2.492942763 seconds time elapsed
#
Reported-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Acked-by: Elena Reshetova <elena.reshetova@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: Krister Johansen <kjlx@templeofstupid.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Sudeep Holla <Sudeep.Holla@arm.com>
Cc: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 79c5fe6db8c7 ("perf cgroup: Convert cgroup_sel.refcnt from atomic_t to refcount_t")
Link: http://lkml.kernel.org/n/tip-l7ovfblq14ip2i08m1g0fkhv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/cgroup.c')
-rw-r--r-- | tools/perf/util/cgroup.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c index 03347748f3fa..0e77bc9e5f3c 100644 --- a/tools/perf/util/cgroup.c +++ b/tools/perf/util/cgroup.c @@ -98,8 +98,10 @@ static int add_cgroup(struct perf_evlist *evlist, char *str) cgrp = counter->cgrp; if (!cgrp) continue; - if (!strcmp(cgrp->name, str)) + if (!strcmp(cgrp->name, str)) { + refcount_inc(&cgrp->refcnt); break; + } cgrp = NULL; } @@ -110,6 +112,7 @@ static int add_cgroup(struct perf_evlist *evlist, char *str) return -1; cgrp->name = str; + refcount_set(&cgrp->refcnt, 1); cgrp->fd = open_cgroup(str); if (cgrp->fd == -1) { @@ -128,12 +131,11 @@ static int add_cgroup(struct perf_evlist *evlist, char *str) goto found; n++; } - if (refcount_read(&cgrp->refcnt) == 0) + if (refcount_dec_and_test(&cgrp->refcnt)) free(cgrp); return -1; found: - refcount_inc(&cgrp->refcnt); counter->cgrp = cgrp; return 0; } |