On Tue 18-09-18 07:56:03, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: c0747ad363ff Merge tag 'linux-kselftest-4.19-rc5' of git:/.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1483a8c9400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5fa12be50bca08d8 > dashboard link: https://syzkaller.appspot.com/bug?extid=5373a556df9f9fec7e90 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+5373a556df9f9fec7e90@xxxxxxxxxxxxxxxxxxxxxxxxx > > ------------[ cut here ]------------ > kernel BUG at include/linux/page-flags.h:273! Hum, looks like PageTail (i.e. the lowest bit of LRU pointer) got set for a pagecache page we try to writeback. No idea how that's possible... Honza > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > CPU: 1 PID: 9734 Comm: kworker/u4:1 Not tainted 4.19.0-rc4+ #18 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Workqueue: writeback wb_workfn (flush-7:4) > RIP: 0010:PageWaiters include/linux/page-flags.h:273 [inline] > RIP: 0010:wake_up_page mm/filemap.c:1069 [inline] > RIP: 0010:end_page_writeback+0x769/0x950 mm/filemap.c:1233 > Code: ff e8 6b 25 e2 ff 48 8b 85 30 fe ff ff 4c 8d 70 ff e9 d9 fa ff ff e8 > 56 25 e2 ff 48 c7 c6 e0 24 12 88 48 89 df e8 a7 cc 13 00 <0f> 0b e8 40 25 e2 > ff 48 c7 c6 60 25 12 88 48 89 df e8 91 cc 13 00 > RSP: 0018:ffff8801b91e5288 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: ffffea00064dabc0 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffffffff81b08db9 RDI: ffffed003723ca42 > RBP: ffff8801b91e5460 R08: ffff880157a40400 R09: ffffed003b5e4fe8 > kobject: 'loop0' (00000000d6ad330d): kobject_uevent_env > R10: ffffed003b5e4fe8 R11: ffff8801daf27f47 R12: 0000000000000001 > R13: 1ffff1003723ca53 R14: 1ffff1003723ca7f R15: dffffc0000000000 > FS: 0000000000000000(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f6134b6cc90 CR3: 00000001cc363000 CR4: 00000000001406e0 > kobject: 'loop0' (00000000d6ad330d): fill_kobj_path: path = > '/devices/virtual/block/loop0' > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > page_endio+0x67c/0xb60 mm/filemap.c:1260 > mpage_end_io+0x144/0x1e0 fs/mpage.c:54 > bio_endio+0x5d2/0xb80 block/bio.c:1774 > generic_make_request_checks+0x5f6/0x26c0 block/blk-core.c:2347 > generic_make_request+0x2bd/0x15a0 block/blk-core.c:2401 > submit_bio+0xba/0x460 block/blk-core.c:2566 > mpage_bio_submit fs/mpage.c:66 [inline] > __mpage_writepage+0x1515/0x1d30 fs/mpage.c:627 > write_cache_pages+0xd8e/0x1e50 mm/page-writeback.c:2239 > mpage_writepages+0x14c/0x320 fs/mpage.c:730 > fat_writepages+0x24/0x30 fs/fat/inode.c:198 > do_writepages+0x9a/0x1a0 mm/page-writeback.c:2340 > __writeback_single_inode+0x20a/0x1620 fs/fs-writeback.c:1323 > writeback_sb_inodes+0x71f/0x11d0 fs/fs-writeback.c:1587 > __writeback_inodes_wb+0x1b9/0x340 fs/fs-writeback.c:1656 > wb_writeback+0xa73/0xfc0 fs/fs-writeback.c:1765 > wb_check_start_all fs/fs-writeback.c:1889 [inline] > wb_do_writeback fs/fs-writeback.c:1915 [inline] > wb_workfn+0xee9/0x1790 fs/fs-writeback.c:1949 > process_one_work+0xc90/0x1b90 kernel/workqueue.c:2153 > worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 > kthread+0x35a/0x420 kernel/kthread.c:246 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 > Modules linked in: > kobject: 'loop5' (0000000003a73ee3): kobject_uevent_env > kobject: 'loop5' (0000000003a73ee3): fill_kobj_path: path = > '/devices/virtual/block/loop5' > ---[ end trace b1bf6d33e16c103c ]--- > RIP: 0010:PageWaiters include/linux/page-flags.h:273 [inline] > RIP: 0010:wake_up_page mm/filemap.c:1069 [inline] > RIP: 0010:end_page_writeback+0x769/0x950 mm/filemap.c:1233 > Code: ff e8 6b 25 e2 ff 48 8b 85 30 fe ff ff 4c 8d 70 ff e9 d9 fa ff ff e8 > 56 25 e2 ff 48 c7 c6 e0 24 12 88 48 89 df e8 a7 cc 13 00 <0f> 0b e8 40 25 e2 > ff 48 c7 c6 60 25 12 88 48 89 df e8 91 cc 13 00 > RSP: 0018:ffff8801b91e5288 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: ffffea00064dabc0 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffffffff81b08db9 RDI: ffffed003723ca42 > kobject: 'loop2' (0000000001c28b7c): kobject_uevent_env > RBP: ffff8801b91e5460 R08: ffff880157a40400 R09: ffffed003b5e4fe8 > kobject: 'loop2' (0000000001c28b7c): fill_kobj_path: path = > '/devices/virtual/block/loop2' > R10: ffffed003b5e4fe8 R11: ffff8801daf27f47 R12: 0000000000000001 > R13: 1ffff1003723ca53 R14: 1ffff1003723ca7f R15: dffffc0000000000 > FS: 0000000000000000(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 > kobject: 'loop3' (0000000091672ed1): kobject_uevent_env > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > kobject: 'loop3' (0000000091672ed1): fill_kobj_path: path = > '/devices/virtual/block/loop3' > CR2: 0000001b3202d000 CR3: 00000001cad9f000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot. -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
