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authorYanmin Zhang <yanmin_zhang@linux.intel.com>2012-05-23 15:39:45 +0000
committerDavid S. Miller <davem@davemloft.net>2012-05-24 00:28:21 -0400
commite49cc0da7283088c5e03d475ffe2fdcb24a6d5b1 (patch)
tree2bd3c141e3c0a2e671870fb4fe46793f8beee3ba /net
parent31fe62b9586643953f0c0c37a6357dafc69034e2 (diff)
downloadlinux-e49cc0da7283088c5e03d475ffe2fdcb24a6d5b1.tar.gz
ipv4: fix the rcu race between free_fib_info and ip_route_output_slow
We hit a kernel OOPS. <3>[23898.789643] BUG: sleeping function called from invalid context at /data/buildbot/workdir/ics/hardware/intel/linux-2.6/arch/x86/mm/fault.c:1103 <3>[23898.862215] in_atomic(): 0, irqs_disabled(): 0, pid: 10526, name: Thread-6683 <4>[23898.967805] HSU serial 0000:00:05.1: 0000:00:05.2:HSU serial prevented me to suspend... <4>[23899.258526] Pid: 10526, comm: Thread-6683 Tainted: G W 3.0.8-137685-ge7742f9 #1 <4>[23899.357404] HSU serial 0000:00:05.1: 0000:00:05.2:HSU serial prevented me to suspend... <4>[23899.904225] Call Trace: <4>[23899.989209] [<c1227f50>] ? pgtable_bad+0x130/0x130 <4>[23900.000416] [<c1238c2a>] __might_sleep+0x10a/0x110 <4>[23900.007357] [<c1228021>] do_page_fault+0xd1/0x3c0 <4>[23900.013764] [<c18e9ba9>] ? restore_all+0xf/0xf <4>[23900.024024] [<c17c007b>] ? napi_complete+0x8b/0x690 <4>[23900.029297] [<c1227f50>] ? pgtable_bad+0x130/0x130 <4>[23900.123739] [<c1227f50>] ? pgtable_bad+0x130/0x130 <4>[23900.128955] [<c18ea0c3>] error_code+0x5f/0x64 <4>[23900.133466] [<c1227f50>] ? pgtable_bad+0x130/0x130 <4>[23900.138450] [<c17f6298>] ? __ip_route_output_key+0x698/0x7c0 <4>[23900.144312] [<c17f5f8d>] ? __ip_route_output_key+0x38d/0x7c0 <4>[23900.150730] [<c17f63df>] ip_route_output_flow+0x1f/0x60 <4>[23900.156261] [<c181de58>] ip4_datagram_connect+0x188/0x2b0 <4>[23900.161960] [<c18e981f>] ? _raw_spin_unlock_bh+0x1f/0x30 <4>[23900.167834] [<c18298d6>] inet_dgram_connect+0x36/0x80 <4>[23900.173224] [<c14f9e88>] ? _copy_from_user+0x48/0x140 <4>[23900.178817] [<c17ab9da>] sys_connect+0x9a/0xd0 <4>[23900.183538] [<c132e93c>] ? alloc_file+0xdc/0x240 <4>[23900.189111] [<c123925d>] ? sub_preempt_count+0x3d/0x50 Function free_fib_info resets nexthop_nh->nh_dev to NULL before releasing fi. Other cpu might be accessing fi. Fixing it by delaying the releasing. With the patch, we ran MTBF testing on Android mobile for 12 hours and didn't trigger the issue. Thank Eric for very detailed review/checking the issue. Signed-off-by: Yanmin Zhang <yanmin_zhang@linux.intel.com> Signed-off-by: Kun Jiang <kunx.jiang@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/fib_semantics.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index a8bdf740543..e5b7182fa09 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -145,6 +145,12 @@ static void free_fib_info_rcu(struct rcu_head *head)
{
struct fib_info *fi = container_of(head, struct fib_info, rcu);
+ change_nexthops(fi) {
+ if (nexthop_nh->nh_dev)
+ dev_put(nexthop_nh->nh_dev);
+ } endfor_nexthops(fi);
+
+ release_net(fi->fib_net);
if (fi->fib_metrics != (u32 *) dst_default_metrics)
kfree(fi->fib_metrics);
kfree(fi);
@@ -156,13 +162,7 @@ void free_fib_info(struct fib_info *fi)
pr_warn("Freeing alive fib_info %p\n", fi);
return;
}
- change_nexthops(fi) {
- if (nexthop_nh->nh_dev)
- dev_put(nexthop_nh->nh_dev);
- nexthop_nh->nh_dev = NULL;
- } endfor_nexthops(fi);
fib_info_cnt--;
- release_net(fi->fib_net);
call_rcu(&fi->rcu, free_fib_info_rcu);
}