From 06d9532fa6b34f12a6d75711162d47c17c1add72 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 13 Aug 2019 22:26:36 +0100 Subject: rxrpc: Fix read-after-free in rxrpc_queue_local() rxrpc_queue_local() attempts to queue the local endpoint it is given and then, if successful, prints a trace line. The trace line includes the current usage count - but we're not allowed to look at the local endpoint at this point as we passed our ref on it to the workqueue. Fix this by reading the usage count before queuing the work item. Also fix the reading of local->debug_id for trace lines, which must be done with the same consideration as reading the usage count. Fixes: 09d2bf595db4 ("rxrpc: Add a tracepoint to track rxrpc_local refcounting") Reported-by: syzbot+78e71c5bab4f76a6a719@syzkaller.appspotmail.com Signed-off-by: David Howells --- include/trace/events/rxrpc.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/trace/events/rxrpc.h') diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index cc1d060cbf13..fa06b528c73c 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -498,10 +498,10 @@ rxrpc_tx_points; #define E_(a, b) { a, b } TRACE_EVENT(rxrpc_local, - TP_PROTO(struct rxrpc_local *local, enum rxrpc_local_trace op, + TP_PROTO(unsigned int local_debug_id, enum rxrpc_local_trace op, int usage, const void *where), - TP_ARGS(local, op, usage, where), + TP_ARGS(local_debug_id, op, usage, where), TP_STRUCT__entry( __field(unsigned int, local ) @@ -511,7 +511,7 @@ TRACE_EVENT(rxrpc_local, ), TP_fast_assign( - __entry->local = local->debug_id; + __entry->local = local_debug_id; __entry->op = op; __entry->usage = usage; __entry->where = where; -- cgit v1.2.3-55-g7522