45 lines
1.5 KiB
Diff
45 lines
1.5 KiB
Diff
From: Ben Hutchings <ben@decadent.org.uk>
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Date: Mon, 27 Jul 2015 00:31:08 +0100
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Subject: perf: Fix double-free of the AUX buffer
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Origin: https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit?id=ee9397a6fb9bc4e52677f5e33eed4abee0f515e6
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If rb->aux_refcount is decremented to zero before rb->refcount,
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__rb_free_aux() may be called twice resulting in a double free of
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rb->aux_pages. Fix this by adding a check to __rb_free_aux().
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Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
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Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Cc: stable@vger.kernel.org
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Fixes: 57ffc5ca679f ("perf: Fix AUX buffer refcounting")
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Link: http://lkml.kernel.org/r/1437953468.12842.17.camel@decadent.org.uk
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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---
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kernel/events/ring_buffer.c | 10 ++++++----
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1 file changed, 6 insertions(+), 4 deletions(-)
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--- a/kernel/events/ring_buffer.c
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+++ b/kernel/events/ring_buffer.c
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@@ -559,11 +559,13 @@ static void __rb_free_aux(struct ring_bu
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rb->aux_priv = NULL;
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}
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- for (pg = 0; pg < rb->aux_nr_pages; pg++)
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- rb_free_aux_page(rb, pg);
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+ if (rb->aux_nr_pages) {
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+ for (pg = 0; pg < rb->aux_nr_pages; pg++)
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+ rb_free_aux_page(rb, pg);
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- kfree(rb->aux_pages);
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- rb->aux_nr_pages = 0;
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+ kfree(rb->aux_pages);
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+ rb->aux_nr_pages = 0;
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+ }
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}
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void rb_free_aux(struct ring_buffer *rb)
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