From 2f10a61cee8fdb9f8da90f5db687e1862b22cf06 Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Sun, 31 Dec 2017 16:18:56 +0100 Subject: xfrm: fix rcu usage in xfrm_get_type_offload request_module can sleep, thus we cannot hold rcu_read_lock() while calling it. The function also jumps back and takes rcu_read_lock() again (in xfrm_state_get_afinfo()), resulting in an imbalance. This codepath is triggered whenever a new offloaded state is created. Fixes: ffdb5211da1c ("xfrm: Auto-load xfrm offload modules") Reported-by: syzbot+ca425f44816d749e8eb49755567a75ee48cf4a30@syzkaller.appspotmail.com Signed-off-by: Sabrina Dubroca Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_state.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/xfrm') diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 1e80f68e2266..429957412633 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -313,13 +313,14 @@ retry: if ((type && !try_module_get(type->owner))) type = NULL; + rcu_read_unlock(); + if (!type && try_load) { request_module("xfrm-offload-%d-%d", family, proto); try_load = 0; goto retry; } - rcu_read_unlock(); return type; } -- cgit v1.2.3