commit 8caa2434cd52ac4056f4ec32b423d11a4dc7eaf5
Author: Willy Tarreau <w@1wt.eu>
Date:   Thu Feb 28 15:55:18 2019 +0100

    BUG/MEDIUM: list: fix LIST_POP_LOCKED's removal of the last pointer
    
    There was a typo making the last updated pointer be the pre-last element's
    prev instead of the last's prev element. It didn't show up during early
    tests because the contention is very rare on this one  and it's implicitly
    recovered when updating the pointers to go to the next element, but it was
    clearly visible in the listener_accept() tests by having all threads block
    on LIST_POP_LOCKED() with n==p==LLIST_BUSY.
    
    This will have to be backported if commit a8434ec14 ("MINOR: lists:
    Implement locked variations.") is backported.
    
    (cherry picked from commit 285192564d2a7d6eff077d91758b603ba7f2b10a)
    Signed-off-by: Willy Tarreau <w@1wt.eu>
    (cherry picked from commit 20fcf3a0e188551ef185c02c7fb28314de6e412e)
    Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>

diff --git a/include/common/mini-clist.h b/include/common/mini-clist.h
index 779f81da..51c61051 100644
--- a/include/common/mini-clist.h
+++ b/include/common/mini-clist.h
@@ -292,7 +292,7 @@ struct cond_wordlist {
 				 __ha_barrier_store();                     \
 				 continue;                                 \
 			 }                                                 \
-			 p2 = HA_ATOMIC_XCHG(&n2->p, LLIST_BUSY);          \
+			 p2 = HA_ATOMIC_XCHG(&n->p, LLIST_BUSY);           \
 			 if (p2 == LLIST_BUSY) {                           \
 				 n->n = n2;                                \
 				 n->p = p;                                 \