Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Conflicts:
	net/netfilter/core.c
	net/netfilter/nf_tables_netdev.c

Resolve two conflicts before pull request for David's net-next tree:

1) Between c73c24849011 ("netfilter: nf_tables_netdev: remove redundant
   ip_hdr assignment") from the net tree and commit ddc8b6027ad0
   ("netfilter: introduce nft_set_pktinfo_{ipv4, ipv6}_validate()").

2) Between e8bffe0cf964 ("net: Add _nf_(un)register_hooks symbols") and
   Aaron Conole's patches to replace list_head with single linked list.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 11 insertions, 4 deletions

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index ae9b90dc9a5a..257fa460b846 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -330,15 +330,22 @@ void *perf_aux_output_begin(struct perf_output_handle *handle,
 	if (!rb)
 		return NULL;
 
-	if (!rb_has_aux(rb) || !atomic_inc_not_zero(&rb->aux_refcount))
+	if (!rb_has_aux(rb))
 		goto err;
 
 	/*
-	 * If rb::aux_mmap_count is zero (and rb_has_aux() above went through),
-	 * the aux buffer is in perf_mmap_close(), about to get freed.
+	 * If aux_mmap_count is zero, the aux buffer is in perf_mmap_close(),
+	 * about to get freed, so we leave immediately.
+	 *
+	 * Checking rb::aux_mmap_count and rb::refcount has to be done in
+	 * the same order, see perf_mmap_close. Otherwise we end up freeing
+	 * aux pages in this path, which is a bug, because in_atomic().
 	 */
 	if (!atomic_read(&rb->aux_mmap_count))
-		goto err_put;
+		goto err;
+
+	if (!atomic_inc_not_zero(&rb->aux_refcount))
+		goto err;
 
 	/*
 	 * Nesting is not supported for AUX area, make sure nested