Messages in this thread Patch in this message | | | Date | Wed, 30 Sep 2009 16:19:39 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH,TRIVIAL] Fix csum_ipv6_magic asm memory clobber |
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On Thu, 1 Oct 2009 01:01:38 +0200 Samuel Thibault <samuel.thibault@ens-lyon.org> wrote:
> Actually it hit Hurd's pfinetv4 when we tried to compile it with > gcc-4.3 (bogus checksums).
That's important information! I updated the changelog and added the Cc:stable, thanks.
Full patch for netdev benefit:
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Just like ip_fast_csum, the assembly snippet in csum_ipv6_magic needs a memory clobber, as it is only passed the address of the buffer, not a memory reference to the buffer itself.
This caused failures in Hurd's pfinetv4 when we tried to compile it with gcc-4.3 (bogus checksums).
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Andi Kleen <andi@firstfloor.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> ---
arch/x86/include/asm/checksum_32.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN arch/x86/include/asm/checksum_32.h~x86-fix-csum_ipv6_magic-asm-memory-clobber arch/x86/include/asm/checksum_32.h --- a/arch/x86/include/asm/checksum_32.h~x86-fix-csum_ipv6_magic-asm-memory-clobber +++ a/arch/x86/include/asm/checksum_32.h @@ -161,7 +161,8 @@ static inline __sum16 csum_ipv6_magic(co "adcl $0, %0 ;\n" : "=&r" (sum) : "r" (saddr), "r" (daddr), - "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)); + "r" (htonl(len)), "r" (htonl(proto)), "0" (sum) + : "memory"); return csum_fold(sum); } _
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