[PATCH] xfrm: don't call xfrm_policy_cache_flush under xfrm_state_lock

I might be wrong but it doesn't look like xfrm_state_lock is required
for xfrm_policy_cache_flush and calling it under this lock triggers both
"sleeping function called from invalid context" and "possible circular
locking dependency detected" warnings on flush.

Fixes: ec30d78c14a8 xfrm: add xdst pcpu cache
Signed-off-by: Artem Savkov <redacted>
---
 net/xfrm/xfrm_state.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 0dab1cd79ce4..12213477cd3a 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c

@@ -732,12 +732,12 @@ int xfrm_state_flush(struct net *net, u8 proto, bool task_valid)
 			}
 		}
 	}
+out:
+	spin_unlock_bh(&net->xfrm.xfrm_state_lock);
 	if (cnt) {
 		err = 0;
 		xfrm_policy_cache_flush();
 	}
-out:
-	spin_unlock_bh(&net->xfrm.xfrm_state_lock);
 	return err;
 }
 EXPORT_SYMBOL(xfrm_state_flush);

-- 
2.13.5

Artem Savkov [off-list ref] wrote:

I might be wrong but it doesn't look like xfrm_state_lock is required
for xfrm_policy_cache_flush and calling it under this lock triggers both
"sleeping function called from invalid context" and "possible circular
locking dependency detected" warnings on flush.

Fixes: ec30d78c14a8 xfrm: add xdst pcpu cache
Signed-off-by: Artem Savkov <redacted>

You're right, its not needed (and wrong).

Acked-by: Florian Westphal <fw@strlen.de>

On Wed, Sep 27, 2017 at 02:31:03PM +0200, Florian Westphal wrote:

Artem Savkov [off-list ref] wrote:

quoted

I might be wrong but it doesn't look like xfrm_state_lock is required
for xfrm_policy_cache_flush and calling it under this lock triggers both
"sleeping function called from invalid context" and "possible circular
locking dependency detected" warnings on flush.

Fixes: ec30d78c14a8 xfrm: add xdst pcpu cache
Signed-off-by: Artem Savkov <redacted>

You're right, its not needed (and wrong).

Acked-by: Florian Westphal <fw@strlen.de>

Applied to the ipsec tree, thanks everyone!