[PATCH] Revert "kernel/relay.c: fix potential memory leak"

[Eric Biggers]

From: Eric Biggers <ebiggers@xxxxxxxxxx>

This reverts commit ba62bafe942b159a6109cbec780d36496e06b6c5.

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.

Fixes: ba62bafe942b ("kernel/relay.c: fix potential memory leak")
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.7+
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
 kernel/relay.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/relay.c b/kernel/relay.c
index 39a9dfc69486..55da824f4adc 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -611,7 +611,6 @@ struct rchan *relay_open(const char *base_filename,
 
 	kref_put(&chan->kref, relay_destroy_channel);
 	mutex_unlock(&relay_channels_mutex);
-	kfree(chan);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(relay_open);
-- 
2.16.0.rc1.238.g530d649a79-goog