Subject: + mm-numa-bugfix-for-last_cpupid_not_in_page_flags-v3.patch added to -mm tree To: pingfank@xxxxxxxxxxxxxxxxxx,aneesh.kumar@xxxxxxxxxxxxxxxxxx,benh@xxxxxxxxxxxxxxxxxxx,mel@xxxxxxxxx,paulus@xxxxxxxxx,peterz@xxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Fri, 28 Feb 2014 13:52:33 -0800 The patch titled Subject: mm: numa: bugfix for LAST_CPUPID_NOT_IN_PAGE_FLAGS has been added to the -mm tree. Its filename is mm-numa-bugfix-for-last_cpupid_not_in_page_flags-v3.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-numa-bugfix-for-last_cpupid_not_in_page_flags-v3.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-numa-bugfix-for-last_cpupid_not_in_page_flags-v3.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> Subject: mm: numa: bugfix for LAST_CPUPID_NOT_IN_PAGE_FLAGS When doing some numa tests on powerpc, I triggered an oops bug. I find it is caused by using page->_last_cpupid. It should be initialized as "-1 & LAST_CPUPID_MASK", but not "-1". Otherwise, in task_numa_fault(), we will miss the checking (last_cpupid == (-1 & LAST_CPUPID_MASK)). And finally cause an oops bug in task_numa_group(), since the online cpu is less than possible cpu. This happen with CONFIG_SPARSE_VMEMMAP disabled Call trace: [ 55.978091] SMP NR_CPUS=64 NUMA PowerNV [ 55.978118] Modules linked in: [ 55.978145] CPU: 24 PID: 804 Comm: systemd-udevd Not tainted3.13.0-rc1+ #32 [ 55.978183] task: c000001e2746aa80 ti: c000001e32c50000 task.ti:c000001e32c50000 [ 55.978219] NIP: c0000000000f5ad0 LR: c0000000000f5ac8 CTR:c000000000913cf0 [ 55.978256] REGS: c000001e32c53510 TRAP: 0300 Not tainted(3.13.0-rc1+) [ 55.978286] MSR: 9000000000009032 <SF,HV,EE,ME,IR,DR,RI> CR:28024424 XER: 20000000 [ 55.978380] CFAR: c000000000009324 DAR: 7265717569726857 DSISR:40000000 SOFTE: 1 GPR00: c0000000000f5ac8 c000001e32c53790 c000000001f343380000000000000021 GPR04: 0000000000000000 0000000000000031 c000000001f743380000ffffffffffff GPR08: 0000000000000001 7265717569726573 00000000000000000000000000000000 GPR12: 0000000028024422 c00000000ffdd800 00000000296b2e640000000000000020 GPR16: 0000000000000002 0000000000000003 c000001e2f8e4658c000001e25c1c1d8 GPR20: c000001e2f8e4000 c000000001f7a858 00000000000006580000000040000392 GPR24: 00000000000000a8 c000001e33c1a400 00000000000001d8c000001e25c1c000 GPR28: c000001e33c37ff0 0007837840000392 000000000000003fc000001e32c53790 [ 55.978903] NIP [c0000000000f5ad0] .task_numa_fault+0x1470/0x2370 [ 55.978934] LR [c0000000000f5ac8] .task_numa_fault+0x1468/0x2370 [ 55.978964] Call Trace: [ 55.978978] [c000001e32c53790] [c0000000000f5ac8].task_numa_fault+0x1468/0x2370 (unreliable) [ 55.979036] [c000001e32c539e0] [c00000000020a820].do_numa_page+0x480/0x4a0 [ 55.979072] [c000001e32c53b10] [c00000000020bfec].handle_mm_fault+0x4ec/0xc90 [ 55.979123] [c000001e32c53c00] [c000000000e88c98].do_page_fault+0x3a8/0x890 [ 55.979161] [c000001e32c53e30] [c000000000009568]handle_page_fault+0x10/0x30 [ 55.979197] Instruction dump: [ 55.979216] 3c82fefb 3884b138 48d9cff1 60000000 48000574 3c62fefb3863af78 3c82fefb [ 55.979277] 3884b138 48d9cfd5 60000000 e93f0100 <812902e4> 7d2907b45529063e 7d2a07b4 [ 55.979354] ---[ end trace 15f2510da5ae07cf ]--- Signed-off-by: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mm.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff -puN include/linux/mm.h~mm-numa-bugfix-for-last_cpupid_not_in_page_flags-v3 include/linux/mm.h --- a/include/linux/mm.h~mm-numa-bugfix-for-last_cpupid_not_in_page_flags-v3 +++ a/include/linux/mm.h @@ -767,7 +767,7 @@ static inline bool __cpupid_match_pid(pi #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS static inline int page_cpupid_xchg_last(struct page *page, int cpupid) { - return xchg(&page->_last_cpupid, cpupid); + return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK); } static inline int page_cpupid_last(struct page *page) @@ -776,7 +776,7 @@ static inline int page_cpupid_last(struc } static inline void page_cpupid_reset_last(struct page *page) { - page->_last_cpupid = -1; + page->_last_cpupid = -1 & LAST_CPUPID_MASK; } #else static inline int page_cpupid_last(struct page *page) _ Patches currently in -mm which might be from pingfank@xxxxxxxxxxxxxxxxxx are mm-numa-bugfix-for-last_cpupid_not_in_page_flags-v3.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html