On Tue, Jun 3, 2014 at 8:21 AM, Dave Jones <davej@xxxxxxxxxx> wrote: > I'm still seeing this one from time to time, though it takes me quite a while to hit it, > despite my attempts at trying to narrow down the set of syscalls that cause it. > > kernel BUG at mm/filemap.c:202! > invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > CPU: 3 PID: 3013 Comm: trinity-c361 Not tainted 3.15.0-rc8+ #225 > task: ffff88006c610000 ti: ffff880055960000 task.ti: ffff880055960000 > RIP: 0010:[<ffffffffac158e28>] [<ffffffffac158e28>] __delete_from_page_cache+0x318/0x360 > RSP: 0018:ffff880055963b90 EFLAGS: 00010046 > RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffff880146f68388 > RDX: 000000000000022a RSI: ffffffffaca8db38 RDI: ffffffffaca62b17 > RBP: ffff880055963be0 R08: 0000000000000002 R09: ffff88000613d530 > R10: ffff880055963ba8 R11: ffff880007f49a40 R12: ffffea0006795880 > R13: ffff880143232ad0 R14: 0000000000000000 R15: ffff880143232ad8 > FS: 00007f1e40673700(0000) GS:ffff88024d180000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f1e404e6000 CR3: 00000000603eb000 CR4: 00000000001407e0 > DR0: 0000000001bb1000 DR1: 0000000002537000 DR2: 00000000016a5000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > Stack: > ffff880143232ae8 0000000000000000 ffff88000613d530 ffff88000613d568 > 0000000008828259 ffffea0006795880 ffff880143232ae8 0000000000000000 > 0000000000000002 0000000000000002 ffff880055963c08 ffffffffac158eae > Call Trace: > [<ffffffffac158eae>] delete_from_page_cache+0x3e/0x70 > [<ffffffffac16921b>] truncate_inode_page+0x5b/0x90 > [<ffffffffac174493>] shmem_undo_range+0x363/0x790 > [<ffffffffac1748d4>] shmem_truncate_range+0x14/0x30 > [<ffffffffac174bcf>] shmem_fallocate+0x9f/0x340 > [<ffffffffac324d40>] ? timerqueue_add+0x60/0xb0 > [<ffffffffac1c5ff6>] do_fallocate+0x116/0x1a0 > [<ffffffffac182260>] SyS_madvise+0x3c0/0x870 > [<ffffffffac346b33>] ? __this_cpu_preempt_check+0x13/0x20 > [<ffffffffac74c41f>] tracesys+0xdd/0xe2 > Code: ff ff 01 41 f6 c6 01 48 8b 45 c8 75 16 4c 89 30 e9 70 fe ff ff 66 0f 1f 44 00 00 0f 0b 66 0f 1f 44 00 00 0f 0b 66 0f 1f 44 00 00 <0f> 0b 66 0f 1f 44 00 00 41 54 9d e8 78 9e fd ff e9 8c fe ff ff > RIP [<ffffffffac158e28>] __delete_from_page_cache+0x318/0x360 > > There was also another variant of the same BUG with a slighty different stack trace. > > kernel BUG at mm/filemap.c:202! > invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > CPU: 2 PID: 6928 Comm: trinity-c45 Not tainted 3.15.0-rc5+ #208 > task: ffff88023669d0a0 ti: ffff880186146000 task.ti: ffff880186146000 > RIP: 0010:[<ffffffff8415ba05>] [<ffffffff8415ba05>] __delete_from_page_cache+0x315/0x320 > RSP: 0018:ffff880186147b18 EFLAGS: 00010046 > RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000002 > RDX: 000000000000012a RSI: ffffffff84a9a83c RDI: ffffffff84a6e0c0 > RBP: ffff880186147b68 R08: 0000000000000002 R09: ffff88002669e668 > R10: ffff880186147b30 R11: 0000000000000000 R12: ffffea0008b067c0 > R13: ffff880025355670 R14: 0000000000000000 R15: ffff880025355678 > FS: 00007fc10026f740(0000) GS:ffff880244400000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00002ab350f5c004 CR3: 000000018566c000 CR4: 00000000001407e0 > DR0: 0000000001989000 DR1: 0000000000944000 DR2: 0000000002494000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > Stack: > ffff880025355688 ffff8800253556a0 ffff88002669e668 ffff88002669e6a0 > 000000008ea099ef ffffea0008b067c0 ffff880025355688 0000000000000000 > 0000000000000000 0000000000000002 ffff880186147b90 ffffffff8415ba4d > Call Trace: > [<ffffffff8415ba4d>] delete_from_page_cache+0x3d/0x70 > [<ffffffff8416b0ab>] truncate_inode_page+0x5b/0x90 > [<ffffffff84175f0b>] shmem_undo_range+0x30b/0x780 > [<ffffffff84176394>] shmem_truncate_range+0x14/0x30 > [<ffffffff8417647d>] shmem_evict_inode+0xcd/0x150 > [<ffffffff841e4b17>] evict+0xa7/0x170 > [<ffffffff841e5435>] iput+0xf5/0x180 > [<ffffffff841df8a0>] dentry_kill+0x260/0x2d0 > [<ffffffff841df97c>] dput+0x6c/0x110 > [<ffffffff841c92a9>] __fput+0x189/0x200 > [<ffffffff841c936e>] ____fput+0xe/0x10 > [<ffffffff84090484>] task_work_run+0xb4/0xe0 > [<ffffffff8406ee42>] do_exit+0x302/0xb80 > [<ffffffff84349e13>] ? __this_cpu_preempt_check+0x13/0x20 > [<ffffffff8407073c>] do_group_exit+0x4c/0xc0 > [<ffffffff840707c4>] SyS_exit_group+0x14/0x20 > [<ffffffff8475bf64>] tracesys+0xdd/0xe2 > Code: 4c 89 30 e9 80 fe ff ff 48 8b 75 c0 4c 89 ff e8 82 8f 1c 00 84 c0 0f 85 6c fe ff ff e9 4f fe ff ff 0f 1f 44 00 00 e8 ae 95 5e 00 <0f> 0b e8 04 1c f1 ff 0f 0b 66 90 0f 1f 44 00 00 55 48 89 e5 41 > > > -- > 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> This might shine some light, CONFIG_DEBUG_VM should be =y. --- a/mm/filemap.c +++ b/mm/filemap.c @@ -199,7 +199,7 @@ void __delete_from_page_cache(struct page *page, void *shadow) __dec_zone_page_state(page, NR_FILE_PAGES); if (PageSwapBacked(page)) __dec_zone_page_state(page, NR_SHMEM); - BUG_ON(page_mapped(page)); + VM_BUG_ON_PAGE(page_mapped(page), page); /* * Some filesystems seem to re-dirty the page even after Hugh, As I see shmem truncate/punch hole might race with shmem_getpage_gfp() (when it converts swap-entries into normal pages) and leave pages in truncated area. Am I right? Currently I don't see how exactly this could lead to this problem, but this looks suspicious. I don't like the way in which truncate silently skips page entries when they are changing under it. Completely untested patch follows. --- a/mm/shmem.c +++ b/mm/shmem.c @@ -495,8 +495,9 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, if (radix_tree_exceptional_entry(page)) { if (unfalloc) continue; - nr_swaps_freed += !shmem_free_swap(mapping, - index, page); + if (shmem_free_swap(mapping, index, page)) + goto retry; + nr_swaps_freed++; continue; } @@ -509,10 +510,11 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, } unlock_page(page); } + index++; +retry: pagevec_remove_exceptionals(&pvec); pagevec_release(&pvec); mem_cgroup_uncharge_end(); - index++; } spin_lock(&info->lock); -- 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>