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| author | Ben Hutchings <ben@decadent.org.uk> | 2015-07-27 00:31:08 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-09-13 09:07:39 -0700 |
| commit | db8d87e1cd13809687f39a3da567cb823e1b7576 (patch) | |
| tree | c4c2e531a54fb1012f83ef433c928ff1e2af052b /kernel | |
| parent | b8cae722c4afc4c116dc34e013c82cd5bbc68bb8 (diff) | |
| download | lwn-db8d87e1cd13809687f39a3da567cb823e1b7576.tar.gz lwn-db8d87e1cd13809687f39a3da567cb823e1b7576.zip | |
perf: Fix double-free of the AUX buffer
commit ee9397a6fb9bc4e52677f5e33eed4abee0f515e6 upstream.
If rb->aux_refcount is decremented to zero before rb->refcount,
__rb_free_aux() may be called twice resulting in a double free of
rb->aux_pages. Fix this by adding a check to __rb_free_aux().
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 57ffc5ca679f ("perf: Fix AUX buffer refcounting")
Link: http://lkml.kernel.org/r/1437953468.12842.17.camel@decadent.org.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/ring_buffer.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index 725c416085e3..a7604c81168e 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -547,11 +547,13 @@ static void __rb_free_aux(struct ring_buffer *rb) rb->aux_priv = NULL; } - for (pg = 0; pg < rb->aux_nr_pages; pg++) - rb_free_aux_page(rb, pg); + if (rb->aux_nr_pages) { + for (pg = 0; pg < rb->aux_nr_pages; pg++) + rb_free_aux_page(rb, pg); - kfree(rb->aux_pages); - rb->aux_nr_pages = 0; + kfree(rb->aux_pages); + rb->aux_nr_pages = 0; + } } void rb_free_aux(struct ring_buffer *rb) |