[ovs-dev] [PATCH branch-2.3] ofproto-dpif: Use fat_rwlock instead of ovs_rwlock.

[Ben Pfaff]

On Mon, Apr 06, 2015 at 09:18:58PM -0700, Ansis Atteka wrote:
> This patch fixes a deadlock introduced by commit 6b59b543 (ovs-thread:
> Use fair (but nonrecursive) rwlocks on glibc.)
> 
> If STP is enabled, then a handler thread could have already had
> acquired "xlate_rwlock" in xlate_actions() and then might have
> attempt to acquire it again in xlate_send_packet() leading to
> a deadlock.
> 
> The patch fixes this deadlock by using fat_rwlock that still allows
> to acquire read lock in recursive manner.
> 
> VMware-BZ: #1425671
> 
> Reported-by: Scott Hendricks <shendricks at nicira.com>
> Signed-off-by: Ansis Atteka <aatteka at nicira.com>

This looks good to me at first glance but I'd like a second review.

Can you include the deadlocking backtrace in the commit message?

Would you mind also adding an explanation of how the same bug is avoided
on master?

Thanks,

Ben.