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| author | Peter Zijlstra <peterz@infradead.org> | 2014-10-02 16:17:02 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-10-09 12:18:42 -0700 |
| commit | bee870fc1af7c5109a0f167af3bfe7002a02e7f3 (patch) | |
| tree | 4663f686676fdaf3cecafd453d510bd0c73d87b5 /kernel | |
| parent | 07d209bd092d023976fdb881ba6d4b30fe18aebe (diff) | |
| download | lwn-bee870fc1af7c5109a0f167af3bfe7002a02e7f3.tar.gz lwn-bee870fc1af7c5109a0f167af3bfe7002a02e7f3.zip | |
perf: fix perf bug in fork()
commit 6c72e3501d0d62fc064d3680e5234f3463ec5a86 upstream.
Oleg noticed that a cleanup by Sylvain actually uncovered a bug; by
calling perf_event_free_task() when failing sched_fork() we will not yet
have done the memset() on ->perf_event_ctxp[] and will therefore try and
'free' the inherited contexts, which are still in use by the parent
process. This is bad..
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Sylvain 'ythier' Hitier <sylvain.hitier@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 4 | ||||
| -rw-r--r-- | kernel/fork.c | 5 |
2 files changed, 6 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 6bf387a60399..0b4733447151 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7482,8 +7482,10 @@ int perf_event_init_task(struct task_struct *child) for_each_task_context_nr(ctxn) { ret = perf_event_init_context(child, ctxn); - if (ret) + if (ret) { + perf_event_free_task(child); return ret; + } } return 0; diff --git a/kernel/fork.c b/kernel/fork.c index 2c76e11ba939..514dbc40f98f 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1324,7 +1324,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, goto bad_fork_cleanup_policy; retval = audit_alloc(p); if (retval) - goto bad_fork_cleanup_policy; + goto bad_fork_cleanup_perf; /* copy all the process information */ retval = copy_semundo(clone_flags, p); if (retval) @@ -1522,8 +1522,9 @@ bad_fork_cleanup_semundo: exit_sem(p); bad_fork_cleanup_audit: audit_free(p); -bad_fork_cleanup_policy: +bad_fork_cleanup_perf: perf_event_free_task(p); +bad_fork_cleanup_policy: #ifdef CONFIG_NUMA mpol_put(p->mempolicy); bad_fork_cleanup_cgroup: |