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xfrm: don't call xfrm_policy_cache_flush while holding spinlock 

xfrm_policy_cache_flush can sleep, so it cannot be called while holding
a spinlock.  We could release the lock first, but I don't see why we need
to invoke this function here in first place, the packet path won't reuse
an xdst entry unless its still valid.

While at it, add an annotation to xfrm_policy_cache_flush, it would
have probably caught this bug sooner.

Fixes: ec30d78c14 ("xfrm: add xdst pcpu cache")
Reported-by: syzbot+e149f7d1328c26f9c12f@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
zero-colors
Florian Westphal 2018-01-06 01:13:08 +01:00 committed by Steffen Klassert
parent bcfd09f783
commit b1bdcb59b6
1 changed files with 2 additions and 2 deletions
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4
net/xfrm/xfrm_policy.c
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@ -975,8 +975,6 @@ int xfrm_policy_flush(struct net *net, u8 type, bool task_valid)
}
if (!cnt)
err = -ESRCH;
else
xfrm_policy_cache_flush();
out:
spin_unlock_bh(&net->xfrm.xfrm_policy_lock);
return err;
@ -1744,6 +1742,8 @@ void xfrm_policy_cache_flush(void)
bool found = 0;
int cpu;
might_sleep();
local_bh_disable();
rcu_read_lock();
for_each_possible_cpu(cpu) {