4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Biggers <[email protected]> commit a1be1f3931bfe0a42b46fef77a04593c2b136e7f upstream. This reverts commit ba62bafe942b ("kernel/relay.c: fix potential memory leak"). This commit introduced a double free bug, because 'chan' is already freed by the line: kref_put(&chan->kref, relay_destroy_channel); This bug was found by syzkaller, using the BLKTRACESETUP ioctl. Link: http://lkml.kernel.org/r/[email protected] Fixes: ba62bafe942b ("kernel/relay.c: fix potential memory leak") Signed-off-by: Eric Biggers <[email protected]> Reported-by: syzbot <[email protected]> Reviewed-by: Andrew Morton <[email protected]> Cc: Zhouyi Zhou <[email protected]> Cc: Jens Axboe <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- kernel/relay.c | 1 - 1 file changed, 1 deletion(-) --- a/kernel/relay.c +++ b/kernel/relay.c @@ -611,7 +611,6 @@ free_bufs: kref_put(&chan->kref, relay_destroy_channel); mutex_unlock(&relay_channels_mutex); - kfree(chan); return NULL; } EXPORT_SYMBOL_GPL(relay_open);
