On 12/23/2013 08:54 PM, Wanpeng Li wrote:
Sasha reports unmap_page_range tears down pmd range which is race with thp splitting during page reclaim. Transparent huge page will be splitting during page reclaim. However, split pmd lock which held by __split_trans_huge_lock can't prevent __split_huge_page_refcount running in parallel. This patch fix it by hold compound lock to check if __split_huge_page_refcount is running underneath, in that case zap huge pmd range should be fallback. [ 265.474585] kernel BUG at mm/huge_memory.c:1440! [ 265.475129] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 265.476684] Dumping ftrace buffer: [ 265.477144] (ftrace buffer empty) [ 265.478398] Modules linked in: [ 265.478807] CPU: 8 PID: 11344 Comm: trinity-c206 Tainted: G W 3.13.0-rc5-next-20131223-sasha-00015-gec22156-dirty #8 [ 265.480172] task: ffff8801cb573000 ti: ffff8801cbd3a000 task.ti: ffff8801cbd3a000 [ 265.480172] RIP: 0010:[<ffffffff812c7f70>] [<ffffffff812c7f70>] zap_huge_pmd+0x170/0x1f0 [ 265.480172] RSP: 0000:ffff8801cbd3bc78 EFLAGS: 00010246 [ 265.480172] RAX: 015fffff80090018 RBX: ffff8801cbd3bde8 RCX: ffffffffffffff9c [ 265.480172] RDX: ffffffffffffffff RSI: 0000000000000008 RDI: ffff8800bffd2000 [ 265.480172] RBP: ffff8801cbd3bcb8 R08: 0000000000000000 R09: 0000000000000000 [ 265.480172] R10: 0000000000000001 R11: 0000000000000000 R12: ffffea0002856740 [ 265.480172] R13: ffffea0002d50000 R14: 00007ff915000000 R15: 00007ff930e48fff [ 265.480172] FS: 00007ff934899700(0000) GS:ffff88014d400000(0000) knlGS:0000000000000000 [ 265.480172] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 265.480172] CR2: 00007ff93428a000 CR3: 000000010babe000 CR4: 00000000000006e0 [ 265.480172] Stack: [ 265.480172] 00000000000004dd ffff8801ccbfbb60 ffff8801cbd3bcb8 ffff8801cbb15540 [ 265.480172] 00007ff915000000 00007ff930e49000 ffff8801cbd3bde8 00007ff930e48fff [ 265.480172] ffff8801cbd3bd48 ffffffff812885b6 ffff88005f5d20c0 00007ff915200000 [ 265.480172] Call Trace: [ 265.480172] [<ffffffff812885b6>] unmap_page_range+0x2c6/0x410 [ 265.480172] [<ffffffff81288801>] unmap_single_vma+0x101/0x120 [ 265.480172] [<ffffffff81288881>] unmap_vmas+0x61/0xa0 [ 265.480172] [<ffffffff8128f730>] exit_mmap+0xd0/0x170 [ 265.480172] [<ffffffff81138860>] mmput+0x70/0xe0 [ 265.480172] [<ffffffff8113c89d>] exit_mm+0x18d/0x1a0 [ 265.480172] [<ffffffff811ea355>] ? acct_collect+0x175/0x1b0 [ 265.480172] [<ffffffff8113ed0f>] do_exit+0x26f/0x520 [ 265.480172] [<ffffffff8113f069>] do_group_exit+0xa9/0xe0 [ 265.480172] [<ffffffff8113f0b7>] SyS_exit_group+0x17/0x20 [ 265.480172] [<ffffffff845f10d0>] tracesys+0xdd/0xe2 [ 265.480172] Code: 0f 0b 66 0f 1f 84 00 00 00 00 00 eb fe 66 0f 1f 44 00 00 48 8b 03 f0 48 81 80 50 03 00 00 00 fe ff ff 49 8b 45 00 f6 c4 40 75 10 <0f> 0b 66 0f 1f 44 00 00 eb fe 66 0f 1f 44 00 00 48 8b 03 f0 48 [ 265.480172] RIP [<ffffffff812c7f70>] zap_huge_pmd+0x170/0x1f0 [ 265.480172] RSP <ffff8801cbd3bc78> Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx> Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx> ---
Ran a round of testing overnight. While the BUG seems to be gone I'm now getting: [ 879.815434] BUG: Bad page state in process trinity-c115 pfn:29a00 [ 879.816430] page:ffffea0000a68000 count:0 mapcount:0 mapping: (null) index: 0x7f2f20000 [ 879.817654] page flags: 0x5fffff81084008(uptodate|head|swapbacked|compound_lock) [ 879.818848] Modules linked in: [ 879.819340] CPU: 1 PID: 18824 Comm: trinity-c115 Tainted: G W 3.13.0-rc5-n ext-20131223-sasha-00016-g3010ae9-dirty #13 [ 879.821142] ffffea0000a68000 ffff880188345a58 ffffffff845e014c 0000000000000009 [ 879.822492] ffffea0000a68000 ffff880188345a78 ffffffff8125c301 ffff880188345a78 [ 879.823858] 0000000000000200 ffff880188345ac8 ffffffff8125cd83 ffff880100000000 [ 879.825128] Call Trace: [ 879.825568] [<ffffffff845e014c>] dump_stack+0x52/0x7f [ 879.826425] [<ffffffff8125c301>] bad_page+0xf1/0x120 [ 879.827296] [<ffffffff8125cd83>] free_pages_prepare+0x133/0x1f0 [ 879.828276] [<ffffffff8125f254>] __free_pages_ok+0x24/0x150 [ 879.829267] [<ffffffff8125f39b>] free_compound_page+0x1b/0x20 [ 879.830547] [<ffffffff81267ebc>] __put_compound_page+0x1c/0x30 [ 879.831360] [<ffffffff81267f60>] put_compound_page+0x60/0x2e0 [ 879.832284] [<ffffffff8126824b>] release_pages+0x6b/0x230 [ 879.833230] [<ffffffff8129ef46>] free_pages_and_swap_cache+0xa6/0xd0 [ 879.834297] [<ffffffff81285dff>] tlb_flush_mmu+0x6f/0x90 [ 879.835146] [<ffffffff812c8078>] zap_huge_pmd+0x308/0x410 [ 879.836097] [<ffffffff81288526>] unmap_page_range+0x2c6/0x410 [ 879.837034] [<ffffffff81288771>] unmap_single_vma+0x101/0x120 [ 879.838027] [<ffffffff812887f1>] unmap_vmas+0x61/0xa0 [ 879.838892] [<ffffffff8128f6a0>] exit_mmap+0xd0/0x170 [ 879.839794] [<ffffffff81138860>] mmput+0x70/0xe0 [ 879.841079] [<ffffffff8113c89d>] exit_mm+0x18d/0x1a0 [ 879.841565] [<ffffffff811ea355>] ? acct_collect+0x175/0x1b0 [ 879.842411] [<ffffffff8113ed0f>] do_exit+0x26f/0x520 [ 879.843169] [<ffffffff8113f069>] do_group_exit+0xa9/0xe0 [ 879.844033] [<ffffffff8113f0b7>] SyS_exit_group+0x17/0x20 [ 879.844967] [<ffffffff845f1290>] tracesys+0xdd/0xe2 Thanks, Sasha -- 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>