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Bug#415819: [SPARC] T1k/T2k machines oops in tcp_sendmsg under heavy network load



Package: linux-image-2.6.18-4-686
Version: 2.6.18.dfsg.1-11
Severity: important
Tags: patch

The attached patch by David Miller fixes the oops in tcp_sendmsg on
T1k and T2k machines under heavy network load. Confirmed working by 
multiple people.
-- 
Jurij Smakov                                           jurij@wooyd.org
Key: http://www.wooyd.org/pgpkey/                      KeyID: C99E03CC
Author          : David Miller <davem@davemloft.net>
Date            : Mon, 19 Mar 2007 11:58:19 -0700 (PDT)
Message-ID	: <20070319.115819.63131235.davem@davemloft.net>
Status          : confirmed working
Description     : fixes oops in tcp_sendmsg on T1k/T2k machines under heavy network load

[SPARC64]: store-init needs trailing membar.

The manual says that it is required and we actually have crash reports
where loads see stale data due to not having membars here.

In one case the networking does:

	memset(skb, 0, offsetof(struct sk_buff, truesize));

and then some code later checks skb->nohdr for zero, but it's still
the value that was there before the memset().

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc64/lib/NGbzero.S b/arch/sparc64/lib/NGbzero.S
index e86baec..f10e452 100644
--- a/arch/sparc64/lib/NGbzero.S
+++ b/arch/sparc64/lib/NGbzero.S
@@ -88,6 +88,7 @@ NGbzero_loop:
 	bne,pt		%xcc, NGbzero_loop
 	 add		%o0, 64, %o0
 
+	membar		#Sync
 	wr		%o4, 0x0, %asi
 	brz,pn		%o1, NGbzero_done
 NGbzero_medium:
diff --git a/arch/sparc64/lib/NGmemcpy.S b/arch/sparc64/lib/NGmemcpy.S
index 8e522b3..66063a9 100644
--- a/arch/sparc64/lib/NGmemcpy.S
+++ b/arch/sparc64/lib/NGmemcpy.S
@@ -247,6 +247,8 @@ FUNC_NAME:	/* %o0=dst, %o1=src, %o2=len */
 	/* fall through */
 
 60:	
+	membar		#Sync
+
 	/* %o2 contains any final bytes still needed to be copied
 	 * over. If anything is left, we copy it one byte at a time.
 	 */
diff --git a/arch/sparc64/lib/NGpage.S b/arch/sparc64/lib/NGpage.S
index 7d7c3bb..8ce3a0c 100644
--- a/arch/sparc64/lib/NGpage.S
+++ b/arch/sparc64/lib/NGpage.S
@@ -41,6 +41,7 @@ NGcopy_user_page:	/* %o0=dest, %o1=src, %o2=vaddr */
 	subcc		%g7, 64, %g7
 	bne,pt		%xcc, 1b
 	 add		%o0, 32, %o0
+	membar		#Sync
 	retl
 	 nop
 
@@ -63,6 +64,7 @@ NGclear_user_page:	/* %o0=dest, %o1=vaddr */
 	subcc		%g7, 64, %g7
 	bne,pt		%xcc, 1b
 	 add		%o0, 32, %o0
+	membar		#Sync
 	retl
 	 nop

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