Re: 2.6.9-rc1-mm5 bug in tcp_recvmsg?

[David S. Miller]

On Mon, 13 Sep 2004 16:54:27 -0700
Jesse Barnes <jbarnes@xxxxxxxxxxxx> wrote:

> tg3.  I saw one trace that included do_poll (iirc) and another last week that 
> had sys_select in it.  I'll try to gather some more info.

What you're seeing might be due to the bug fixed by this patch:

# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
#   2004/09/13 12:58:04-07:00 ak@xxxxxx 
#   [NET]: Fix missing spin lock in lltx path.
#   
#   This fixes a silly missing spin lock in the relock path. For some 
#   reason it seems to still work when you don't have spinlock debugging
#   enabled.
#   
#   Please apply.
#   
#   Thanks to Arjan's spinlock debug kernel for finding it.
#   
#   Signed-off-by: Andi Kleen <ak@xxxxxx>
#   Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
# 
# net/sched/sch_generic.c
#   2004/09/13 12:57:46-07:00 ak@xxxxxx +3 -1
#   [NET]: Fix missing spin lock in lltx path.
#   
#   This fixes a silly missing spin lock in the relock path. For some 
#   reason it seems to still work when you don't have spinlock debugging
#   enabled.
#   
#   Please apply.
#   
#   Thanks to Arjan's spinlock debug kernel for finding it.
#   
#   Signed-off-by: Andi Kleen <ak@xxxxxx>
#   Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
# 
diff -Nru a/net/sched/sch_generic.c b/net/sched/sch_generic.c
--- a/net/sched/sch_generic.c	2004-09-13 16:38:39 -07:00
+++ b/net/sched/sch_generic.c	2004-09-13 16:38:39 -07:00
@@ -148,8 +148,10 @@
 					spin_lock(&dev->queue_lock);
 					return -1;
 				}
-				if (ret == NETDEV_TX_LOCKED && nolock)
+				if (ret == NETDEV_TX_LOCKED && nolock) {
+					spin_lock(&dev->queue_lock);
 					goto collision; 
+				}
 			}
 
 			/* NETDEV_TX_BUSY - we need to requeue */
-
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