Hi Sasha, On Fri, Feb 21, 2014 at 01:30:53AM -0500, Sasha Levin wrote: > On 02/10/2014 04:44 PM, Naoya Horiguchi wrote: > >queue_pages_range() does page table walking in its own way now, > >so this patch rewrites it with walk_page_range(). > >One difficulty was that queue_pages_range() needed to check vmas > >to determine whether we queue pages from a given vma or skip it. > >Now we have test_walk() callback in mm_walk for that purpose, > >so we can do the replacement cleanly. queue_pages_test_walk() > >depends on not only the current vma but also the previous one, > >so we use queue_pages->prev to keep it. > > > >ChangeLog v2: > >- rebase onto mmots > >- add VM_PFNMAP check on queue_pages_test_walk() > > > >Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > >--- > > Hi Naoya, > > I'm seeing another spew in today's -next, and it seems to be related > to this patch. Here's the spew (with line numbers instead of kernel > addresses): Thanks. (line numbers translation is very helpful.) This bug looks strange to me. "kernel BUG at mm/hugetlb.c:3580" means we try to do isolate_huge_page() for !PageHead page. But the caller queue_pages_hugetlb() gets the page with "page = pte_page(huge_ptep_get(pte))", so it should be the head page! mm/hugetlb.c:3580 is VM_BUG_ON_PAGE(!PageHead(page), page), so we expect to have dump_page output at this point, is that in your kernel log? Thanks, Naoya Horiguchi > > [ 1411.889835] kernel BUG at mm/hugetlb.c:3580! > [ 1411.890108] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > [ 1411.890468] Dumping ftrace buffer: > [ 1411.890468] (ftrace buffer empty) > [ 1411.890468] Modules linked in: > [ 1411.890468] CPU: 0 PID: 2653 Comm: trinity-c285 Tainted: G > W 3.14.0-rc3-next-20140220-sasha-00008-gab7e7ac-dirty #113 > [ 1411.890468] task: ffff8801be0cb000 ti: ffff8801e471c000 task.ti: ffff8801e471c000 > [ 1411.890468] RIP: 0010:[<mm/hugetlb.c:3580>] [<mm/hugetlb.c:3580>] isolate_huge_page+0x1c/0xb0 > [ 1411.890468] RSP: 0018:ffff8801e471dae8 EFLAGS: 00010246 > [ 1411.890468] RAX: ffff88012b900000 RBX: ffffea0000000000 RCX: 0000000000000000 > [ 1411.890468] RDX: 0000000000000000 RSI: ffff8801be0cbd00 RDI: 0000000000000000 > [ 1411.890468] RBP: ffff8801e471daf8 R08: 0000000000000000 R09: 0000000000000000 > [ 1411.890468] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8801e471dcf8 > [ 1411.890468] R13: ffffffff87d39120 R14: ffff8801e471dbc8 R15: 00007f30b1800000 > [ 1411.890468] FS: 00007f30b50bb700(0000) GS:ffff88012bc00000(0000) knlGS:0000000000000000 > [ 1411.890468] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 1411.890468] CR2: 0000000001609a10 CR3: 00000001e4703000 CR4: 00000000000006f0 > [ 1411.890468] Stack: > [ 1411.890468] 00007f30b1000000 00007f30b0e00000 ffff8801e471db08 ffffffff812a8d71 > [ 1411.890468] ffff8801e471db78 ffffffff81298fb1 00007f30b0d00000 ffff880478a16c38 > [ 1411.890468] ffff8802291c6060 ffffffffffe00000 ffffffffffe00000 ffff8804fd7fa7d0 > [ 1411.890468] Call Trace: > [ 1411.890468] [<mm/mempolicy.c:540>] queue_pages_hugetlb+0x81/0x90 > [ 1411.890468] [<include/linux/spinlock.h:343 mm/pagewalk.c:203>] walk_hugetlb_range+0x111/0x180 > [ 1411.890468] [<mm/pagewalk.c:254>] __walk_page_range+0x25/0x40 > [ 1411.890468] [<mm/pagewalk.c:332>] walk_page_range+0xf2/0x130 > [ 1411.890468] [<mm/mempolicy.c:637>] queue_pages_range+0x6c/0x90 > [ 1411.890468] [<mm/mempolicy.c:492>] ? queue_pages_hugetlb+0x90/0x90 > [ 1411.890468] [<mm/mempolicy.c:521>] ? queue_pages_range+0x90/0x90 > [ 1411.890468] [<mm/mempolicy.c:573>] ? change_prot_numa+0x30/0x30 > [ 1411.890468] [<mm/mempolicy.c:1004>] migrate_to_node+0x77/0xc0 > [ 1411.890468] [<mm/mempolicy.c:1110>] do_migrate_pages+0x1a8/0x230 > [ 1411.890468] [<mm/mempolicy.c:1461>] SYSC_migrate_pages+0x316/0x380 > [ 1411.890468] [<include/linux/rcupdate.h:799 mm/mempolicy.c:1407>] ? SYSC_migrate_pages+0xac/0x380 > [ 1411.890468] [<kernel/sched/cputime.c:681>] ? vtime_account_user+0x91/0xa0 > [ 1411.890468] [<mm/mempolicy.c:1381>] SyS_migrate_pages+0x9/0x10 > [ 1411.890468] [<arch/x86/ia32/ia32entry.S:430>] ia32_do_call+0x13/0x13 > [ 1411.890468] Code: 4c 8b 6d f8 c9 c3 66 0f 1f 84 00 00 00 00 00 55 > 48 89 e5 41 54 49 89 f4 53 48 89 fb 48 8b 07 f6 c4 40 75 13 31 f6 e8 > 84 48 fb ff <0f> 0b 66 90 eb fe 66 0f 1f 44 00 00 8b 4f 1c 48 8d 77 > 1c 85 c9 > [ 1411.890468] RIP [<mm/hugetlb.c:3580>] isolate_huge_page+0x1c/0xb0 > [ 1411.890468] RSP <ffff8801e471dae8> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>