syzbot


INFO: task hung in fuse_lookup

Status: auto-closed as invalid on 2020/01/29 21:30
Reported-by: syzbot+326114f5560676d6b49b@syzkaller.appspotmail.com
First crash: 1149d, last: 997d
similar bugs (7):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in fuse_lookup C error 6 5d09h 1045d 0/1 upstream: reported C repro on 2019/08/14 05:24
linux-4.14 INFO: task hung in fuse_lookup (3) 1 160d 160d 0/1 auto-closed as invalid on 2022/05/15 00:47
upstream INFO: task hung in fuse_lookup (3) C done error 19 148d 1045d 0/22 upstream: reported C repro on 2019/08/14 09:48
linux-4.14 INFO: task hung in fuse_lookup (2) 1 830d 830d 0/1 auto-closed as invalid on 2020/07/13 23:30
upstream INFO: task hung in fuse_lookup 16 1389d 1441d 0/22 closed as invalid on 2018/09/05 12:51
android-49 INFO: task hung in fuse_lookup C 112 959d 1170d 0/3 public: reported C repro on 2019/04/11 08:44
upstream INFO: task hung in fuse_lookup (2) C 13 1223d 1383d 0/22 closed as dup on 2018/09/10 08:43

Sample crash report:
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
INFO: task syz-executor.1:6921 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D24992  6921      1 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 fuse_lock_inode+0xbc/0xf0 fs/fuse/inode.c:365
 fuse_lookup+0x7a/0x380 fs/fuse/dir.c:360
 lookup_slow+0x226/0x440 fs/namei.c:1695
 walk_component+0x698/0x1d00 fs/namei.c:1824
 link_path_walk+0x81f/0x10a0 fs/namei.c:2153
 path_mountpoint+0xac/0x1970 fs/namei.c:2717
 filename_mountpoint+0x16c/0x320 fs/namei.c:2744
 user_path_mountpoint_at+0x3a/0x50 fs/namei.c:2774
 SYSC_umount fs/namespace.c:1730 [inline]
 SyS_umount+0x10c/0x380 fs/namespace.c:1714
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c457
RSP: 002b:00007fff76eb8bb8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00000000000815d8 RCX: 000000000045c457
RDX: 0000000000403520 RSI: 0000000000000002 RDI: 00007fff76eb8c60
RBP: 00000000000005dc R08: 0000000000000000 R09: 0000000000000010
R10: 000000000000000a R11: 0000000000000202 R12: 00007fff76eb9cf0
R13: 0000555556265940 R14: 0000000000000000 R15: 00007fff76eb9cf0

Showing all locks held in the system:
1 lock held by khungtaskd/1013:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81486418>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4541
2 locks held by getty/6870:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6871:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6872:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6873:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6874:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6875:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6876:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.1/6921:
 #0:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff818fcd38>] inode_lock_shared include/linux/fs.h:728 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff818fcd38>] lookup_slow+0x138/0x440 fs/namei.c:1673
 #1:  (&fi->mutex){+.+.}, at: [<ffffffff8219f1ec>] fuse_lock_inode+0xbc/0xf0 fs/fuse/inode.c:365
2 locks held by syz-executor.1/21950:
 #0:  (sb_writers#18){.+.+}, at: [<ffffffff8194d17f>] sb_start_write include/linux/fs.h:1548 [inline]
 #0:  (sb_writers#18){.+.+}, at: [<ffffffff8194d17f>] mnt_want_write+0x3f/0xb0 fs/namespace.c:386
 #1:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff8195ddc1>] inode_lock include/linux/fs.h:718 [inline]
 #1:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff8195ddc1>] vfs_setxattr+0x91/0xf0 fs/xattr.c:219
2 locks held by syz-executor.1/23403:
 #0:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff818fcd38>] inode_lock_shared include/linux/fs.h:728 [inline]
 #0:  (&type->i_mutex_dir_key#7){++++}, at: [<ffffffff818fcd38>] lookup_slow+0x138/0x440 fs/namei.c:1673
 #1:  (&fi->mutex){+.+.}, at: [<ffffffff8219f1ec>] fuse_lock_inode+0xbc/0xf0 fs/fuse/inode.c:365

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1013 Comm: khungtaskd Not tainted 4.14.146 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x138/0x197 lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5e7/0xb90 kernel/hung_task.c:274
 kthread+0x319/0x430 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6746 Comm: rs:main Q:Reg Not tainted 4.14.146 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88808b9963c0 task.stack: ffff88808b2d0000
RIP: 0010:sbitmap_for_each_set include/linux/sbitmap.h:234 [inline]
RIP: 0010:bt_for_each block/blk-mq-tag.c:236 [inline]
RIP: 0010:blk_mq_queue_tag_busy_iter+0x2aa/0x6f0 block/blk-mq-tag.c:350
RSP: 0018:ffff88808b2d72d0 EFLAGS: 00000246
RAX: 1ffff110147d2c00 RBX: ffff8880a3e96000 RCX: 0000000000000080
RDX: 0000000000000000 RSI: ffffffff82c918e0 RDI: ffff8880a3cecb18
RBP: ffff88808b2d73e8 R08: ffff88808b9963c0 R09: 0000000000000004
R10: 0000000000000000 R11: ffff88808b9963c0 R12: 1ffff1101165ae7f
R13: ffff8880a1e43230 R14: ffff8880a3cecb00 R15: dffffc0000000000
FS:  00007fbfed59e700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd8b122eb1 CR3: 00000000a1878000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 blk_mq_in_flight+0xc9/0x100 block/blk-mq.c:118
 part_in_flight+0x23f/0x2b0 block/genhd.c:72
 part_round_stats+0x19c/0x610 block/blk-core.c:1540
 blk_account_io_start+0x535/0x990 block/blk-core.c:2529
 blk_mq_bio_to_request block/blk-mq.c:1545 [inline]
 blk_mq_make_request+0x514/0x1c10 block/blk-mq.c:1749
 generic_make_request block/blk-core.c:2227 [inline]
 generic_make_request+0x205/0xa40 block/blk-core.c:2171
 submit_bio+0x1a5/0x3f0 block/blk-core.c:2301
 submit_bh_wbc+0x550/0x720 fs/buffer.c:3152
 submit_bh fs/buffer.c:3158 [inline]
 __sync_dirty_buffer fs/buffer.c:3244 [inline]
 __sync_dirty_buffer+0xcf/0x260 fs/buffer.c:3235
 sync_dirty_buffer+0x1b/0x20 fs/buffer.c:3257
 ext4_write_inode+0x3c2/0x450 fs/ext4/inode.c:5264
 write_inode fs/fs-writeback.c:1224 [inline]
 __writeback_single_inode+0xb44/0x1120 fs/fs-writeback.c:1423
 writeback_single_inode+0x1fa/0x380 fs/fs-writeback.c:1477
 sync_inode fs/fs-writeback.c:2505 [inline]
 sync_inode_metadata+0x8c/0xb0 fs/fs-writeback.c:2525
 __generic_file_fsync+0x130/0x1a0 fs/libfs.c:988
 ext4_sync_file+0x755/0x12d0 fs/ext4/fsync.c:120
 vfs_fsync_range+0x10e/0x260 fs/sync.c:196
 generic_write_sync include/linux/fs.h:2677 [inline]
 ext4_file_write_iter+0x68a/0xe90 fs/ext4/file.c:279
 call_write_iter include/linux/fs.h:1777 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x4a7/0x6b0 fs/read_write.c:482
 vfs_write+0x198/0x500 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xfd/0x230 fs/read_write.c:582
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fbfeeffc19d
RSP: 002b:00007fbfed59cf90 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000400 RCX: 00007fbfeeffc19d
RDX: 0000000000000400 RSI: 00000000015fa340 RDI: 0000000000000006
RBP: 00000000015fa340 R08: 302b796669746f6e R09: 5d3234383430332e
R10: 676e7568203f2020 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fbfed59d410 R14: 00000000016901d0 R15: 00000000015fa140
Code: 00 0f 85 c0 03 00 00 8b 9d 70 ff ff ff 48 c1 e3 06 49 03 5e 20 48 89 d8 48 c1 e8 03 42 80 3c 38 00 0f 85 93 03 00 00 48 83 3b 00 <75> 77 e8 bf 84 92 fe 83 85 70 ff ff ff 01 8b 85 70 ff ff ff 41 

Crashes (4):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2019/10/01 21:29 linux-4.14.y f6e27dbb1afa b7a87a83 .config log report
ci2-linux-4-14 2019/08/13 20:45 linux-4.14.y 3ffe1e79c174 74d61399 .config log report
ci2-linux-4-14 2019/08/13 18:54 linux-4.14.y 3ffe1e79c174 74d61399 .config log report
ci2-linux-4-14 2019/05/01 23:16 linux-4.14.y fa5941f45d7e 7516d9fa .config log report