On 02/11/2011 23:43, Tony Lindgren wrote: > Commit 87fb4b7b533073eeeaed0b6bf7c2328995f6c075 (net: more > accurate skb truesize) changed the alignment of size. This > can cause problems at least on some machines with NFS root: > > Unhandled fault: alignment exception (0x801) at 0xc183a43a > Internal error: : 801 [#1] PREEMPT > Modules linked in: > CPU: 0 Not tainted (3.1.0-08784-g5eeee4a #733) > pc : [<c02fbba0>] lr : [<c02fbb9c>] psr: 60000013 > sp : c180fef8 ip : 00000000 fp : c181f580 > r10: 00000000 r9 : c044b28c r8 : 00000001 > r7 : c183a3a0 r6 : c1835be0 r5 : c183a412 r4 : 000001f2 > r3 : 00000000 r2 : 00000000 r1 : ffffffe6 r0 : c183a43a > Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel > Control: 0005317f Table: 10004000 DAC: 00000017 > Process swapper (pid: 1, stack limit = 0xc180e270) > Stack: (0xc180fef8 to 0xc1810000) > fee0: 00000024 00000000 > ff00: 00000000 c183b9c0 c183b8e0 c044b28c c0507ccc c019dfc4 c180ff2c c0503cf8 > ff20: c180ff4c c180ff4c 00000000 c1835420 c182c740 c18349c0 c05233c0 00000000 > ff40: 00000000 c00e6bb8 c180e000 00000000 c04dd82c c0507e7c c050cc18 c183b9c0 > ff60: c05233c0 00000000 00000000 c01f34f4 c0430d70 c019d364 c04dd898 c04dd898 > ff80: c04dd82c c0507e7c c180e000 00000000 c04c584c c01f4918 c04dd898 c04dd82c > ffa0: c04ddd28 c180e000 00000000 c0008758 c181fa60 3231d82c 00000037 00000000 > ffc0: 00000000 c04dd898 c04dd82c c04ddd28 00000013 00000000 00000000 00000000 > ffe0: 00000000 c04b2224 00000000 c04b21a0 c001056c c001056c 00000000 00000000 > Function entered at [<c02fbba0>] from [<c019dfc4>] > Function entered at [<c019dfc4>] from [<c01f34f4>] > Function entered at [<c01f34f4>] from [<c01f4918>] > Function entered at [<c01f4918>] from [<c0008758>] > Function entered at [<c0008758>] from [<c04b2224>] > Function entered at [<c04b2224>] from [<c001056c>] > Code: e1a00005 e3a01028 ebfa7cb0 e35a0000 (e5858028) > > Here PC is at __alloc_skb and &shinfo->dataref is unaligned because > skb->end can be unaligned without this patch. > > Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx> > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> > > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -189,6 +189,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, > * aligned memory blocks, unless SLUB/SLAB debug is enabled. > * Both skb->head and skb_shared_info are cache line aligned. > */ > + size = SKB_DATA_ALIGN(size); > size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); > data = kmalloc_node_track_caller(size, gfp_mask, node); > if (!data) Hmm, I dont think this is the right way to fix the bug. There is a problem with your kmalloc() or alignments on your architecture. What is the SMP_CACHE_BYTES value ? -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
