| Message ID | 1361784575.3001.5.camel@ThinkPad-T5421.cn.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Michael Ellerman |
| Headers | show |
On Mon, Feb 25, 2013 at 05:29:35PM +0800, Li Zhong wrote: > This patch tries to fix following issue when CONFIG_DEBUG_PAGEALLOC > is enabled: > > [ 543.075675] ------------[ cut here ]------------ > [ 543.075701] kernel BUG at arch/powerpc/mm/hash_utils_64.c:1239! > [ 543.075714] Oops: Exception in kernel mode, sig: 5 [#1] So the issue is that kernel_map_linear_page() doesn't try the secondary hash slot. > The code is borrowed from that in __hash_page_huge(). It is, and in fact there is another copy in hash_low_64.S - in assembler. So I think we should at least try and keep ourselves to two implementations, one in asm and one in C. So can you split it out into a helper routine called by both kernel_map_linear_page() and __hash_page_huge() ? cheers
On Wed, 2013-04-10 at 12:21 +1000, Michael Ellerman wrote: > On Mon, Feb 25, 2013 at 05:29:35PM +0800, Li Zhong wrote: > > This patch tries to fix following issue when CONFIG_DEBUG_PAGEALLOC > > is enabled: > > > > [ 543.075675] ------------[ cut here ]------------ > > [ 543.075701] kernel BUG at arch/powerpc/mm/hash_utils_64.c:1239! > > [ 543.075714] Oops: Exception in kernel mode, sig: 5 [#1] Hi Michael, Thanks for the review. > So the issue is that kernel_map_linear_page() doesn't try the secondary > hash slot. It seems so. > > The code is borrowed from that in __hash_page_huge(). > > It is, and in fact there is another copy in hash_low_64.S - in assembler. > > So I think we should at least try and keep ourselves to two > implementations, one in asm and one in C. So can you split it out into a > helper routine called by both kernel_map_linear_page() and > __hash_page_huge() ? OK, I'll try to update it as you suggested. Thanks, Zhong > cheers >
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 1b6e127..31c7924 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -1231,11 +1231,28 @@ static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi) int ret; hash = hpt_hash(vpn, PAGE_SHIFT, mmu_kernel_ssize); + +repeat: hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP); ret = ppc_md.hpte_insert(hpteg, vpn, __pa(vaddr), mode, HPTE_V_BOLTED, mmu_linear_psize, mmu_kernel_ssize); + + if (unlikely(ret == -1)) { + hpteg = (~hash & htab_hash_mask) * HPTES_PER_GROUP; + ret = ppc_md.hpte_insert(hpteg, vpn, __pa(vaddr), mode, + HPTE_V_SECONDARY, + mmu_linear_psize, mmu_kernel_ssize); + if (ret == -1) { + if (mftb() & 0x1) + hpteg = (hash & htab_hash_mask) * + HPTES_PER_GROUP; + ppc_md.hpte_remove(hpteg); + goto repeat; + } + } + BUG_ON (ret < 0); spin_lock(&linear_map_hash_lock); BUG_ON(linear_map_hash_slots[lmi] & 0x80);
This patch tries to fix following issue when CONFIG_DEBUG_PAGEALLOC is enabled: [ 543.075675] ------------[ cut here ]------------ [ 543.075701] kernel BUG at arch/powerpc/mm/hash_utils_64.c:1239! [ 543.075714] Oops: Exception in kernel mode, sig: 5 [#1] [ 543.075722] PREEMPT SMP NR_CPUS=16 DEBUG_PAGEALLOC NUMA pSeries [ 543.075741] Modules linked in: binfmt_misc ehea [ 543.075759] NIP: c000000000036eb0 LR: c000000000036ea4 CTR: c00000000005a594 [ 543.075771] REGS: c0000000a90832c0 TRAP: 0700 Not tainted (3.8.0-next-20130222) [ 543.075781] MSR: 8000000000029032 <SF,EE,ME,IR,DR,RI> CR: 22224482 XER: 00000000 [ 543.075816] SOFTE: 0 [ 543.075823] CFAR: c00000000004c200 [ 543.075830] TASK = c0000000e506b750[23934] 'cc1' THREAD: c0000000a9080000 CPU: 1 GPR00: 0000000000000001 c0000000a9083540 c000000000c600a8 ffffffffffffffff GPR04: 0000000000000050 fffffffffffffffa c0000000a90834e0 00000000004ff594 GPR08: 0000000000000001 0000000000000000 000000009592d4d8 c000000000c86854 GPR12: 0000000000000002 c000000006ead300 0000000000a51000 0000000000000001 GPR16: f000000003354380 ffffffffffffffff ffffffffffffff80 0000000000000000 GPR20: 0000000000000001 c000000000c600a8 0000000000000001 0000000000000001 GPR24: 0000000003354380 c000000000000000 0000000000000000 c000000000b65950 GPR28: 0000002000000000 00000000000cd50e 0000000000bf50d9 c000000000c7c230 [ 543.076005] NIP [c000000000036eb0] .kernel_map_pages+0x1e0/0x3f8 [ 543.076016] LR [c000000000036ea4] .kernel_map_pages+0x1d4/0x3f8 [ 543.076025] Call Trace: [ 543.076033] [c0000000a9083540] [c000000000036ea4] .kernel_map_pages+0x1d4/0x3f8 (unreliable) [ 543.076053] [c0000000a9083640] [c000000000167638] .get_page_from_freelist+0x6cc/0x8dc [ 543.076067] [c0000000a9083800] [c000000000167a48] .__alloc_pages_nodemask+0x200/0x96c [ 543.076082] [c0000000a90839c0] [c0000000001ade44] .alloc_pages_vma+0x160/0x1e4 [ 543.076098] [c0000000a9083a80] [c00000000018ce04] .handle_pte_fault+0x1b0/0x7e8 [ 543.076113] [c0000000a9083b50] [c00000000018d5a8] .handle_mm_fault+0x16c/0x1a0 [ 543.076129] [c0000000a9083c00] [c0000000007bf1dc] .do_page_fault+0x4d0/0x7a4 [ 543.076144] [c0000000a9083e30] [c0000000000090e8] handle_page_fault+0x10/0x30 [ 543.076155] Instruction dump: [ 543.076163] 7c630038 78631d88 e80a0000 f8410028 7c0903a6 e91f01de e96a0010 e84a0008 [ 543.076192] 4e800421 e8410028 7c7107b4 7a200fe0 <0b000000> 7f63db78 48785781 60000000 [ 543.076224] ---[ end trace bd5807e8d6ae186b ]--- The code is borrowed from that in __hash_page_huge(). Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> --- arch/powerpc/mm/hash_utils_64.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)