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[net] rxrpc: fix uninitialized pointer dereference in debug code

Message ID 20160808101357.1583011-1-arnd@arndb.de
State Accepted
Commit 55cae7a403f3b52de3dd6e4a614582541c9631af
Headers show

Commit Message

Arnd Bergmann Aug. 8, 2016, 10:13 a.m. UTC
A newly added bugfix caused an uninitialized variable to be
used for printing debug output. This is harmless as long
as the debug setting is disabled, but otherwise leads to an
immediate crash.

gcc warns about this when -Wmaybe-uninitialized is enabled:

net/rxrpc/call_object.c: In function 'rxrpc_release_call':
net/rxrpc/call_object.c:496:163: error: 'sp' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The initialization was removed but one of the users remains.
This adds back the initialization.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Fixes: 372ee16386bb ("rxrpc: Fix races between skb free, ACK generation and replying")
---
I have not tried to understand the longish bugfix patch that
caused this, so I'm not sure whether it's actually safe to
access rxrpc_skb(skb) in this function. Please check if this
is the right fix.
---
 net/rxrpc/call_object.c | 1 +
 1 file changed, 1 insertion(+)

-- 
2.9.0
diff mbox

Patch

diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index c47f14fc5e88..e8c953c48cb8 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -493,6 +493,7 @@  void rxrpc_release_call(struct rxrpc_call *call)
 		       (skb = skb_dequeue(&call->rx_oos_queue))) {
 			spin_unlock_bh(&call->lock);
 
+			sp = rxrpc_skb(skb);
 			_debug("- zap %s %%%u #%u",
 			       rxrpc_pkts[sp->hdr.type],
 			       sp->hdr.serial, sp->hdr.seq);