syzbot


INFO: task hung in exfat_get_block (2)

Status: auto-obsoleted due to no activity on 2025/02/07 20:48
Subsystems: exfat
[Documentation on labels]
First crash: 286d, last: 286d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in exfat_get_block exfat 1 3 445d 501d 0/29 auto-obsoleted due to no activity on 2024/09/02 07:26

Sample crash report:
INFO: task syz.5.142:7031 blocked for more than 143 seconds.
      Not tainted 6.12.0-rc6-syzkaller-00272-gda4373fbcf00 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.142       state:D stack:24704 pid:7031  tgid:7015  ppid:5954   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0x17fa/0x4bd0 kernel/sched/core.c:6690
 __schedule_loop kernel/sched/core.c:6767 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6782
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6839
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 exfat_get_block+0x1c3/0x2180 fs/exfat/inode.c:278
 get_more_blocks fs/direct-io.c:648 [inline]
 do_direct_IO fs/direct-io.c:936 [inline]
 __blockdev_direct_IO+0x1c8e/0x4890 fs/direct-io.c:1243
 blockdev_direct_IO include/linux/fs.h:3280 [inline]
 exfat_direct_IO+0x151/0x400 fs/exfat/inode.c:482
 generic_file_direct_write+0x17a/0x390 mm/filemap.c:3977
 __generic_file_write_iter+0x126/0x230 mm/filemap.c:4141
 exfat_file_write_iter+0x165/0x3f0 fs/exfat/file.c:598
 do_iter_readv_writev+0x600/0x880
 vfs_writev+0x376/0xba0 fs/read_write.c:1064
 do_pwritev fs/read_write.c:1165 [inline]
 __do_sys_pwritev2 fs/read_write.c:1224 [inline]
 __se_sys_pwritev2+0x1ca/0x2d0 fs/read_write.c:1215
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5e2a17e719
RSP: 002b:00007f5e285f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007f5e2a336058 RCX: 00007f5e2a17e719
RDX: 0000000000000001 RSI: 00000000200001c0 RDI: 0000000000000004
RBP: 00007f5e2a1f139e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f5e2a336058 R15: 00007ffef5944d68
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline]
 #0: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:976
1 lock held by khungtaskd/30:
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720
4 locks held by kworker/u8:2/35:
 #0: ffff888143a9e148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff888143a9e148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90000ab7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000ab7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffff8880120920e0 (&type->s_umount_key#51){++++}-{3:3}, at: super_trylock_shared+0x22/0xf0 fs/super.c:562
 #3: ffff8880120900e8 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_write_inode+0xe5/0x1a0 fs/exfat/inode.c:108
3 locks held by kworker/1:1/46:
 #0: ffff88801ac80948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac80948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90000b67d00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000b67d00 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
5 locks held by kworker/u8:3/53:
 #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90000be7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000be7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcb4910 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:580
 #3: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: cleanup_net+0x6af/0xcc0 net/core/net_namespace.c:616
 #4: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
 #4: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976
2 locks held by kworker/u8:4/61:
2 locks held by kworker/u8:6/3421:
2 locks held by getty/5582:
 #0: ffff8880304c80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
3 locks held by syz.5.142/7016:
3 locks held by syz.5.142/7031:
 #0: ffff888012092420 (sb_writers#13){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2931 [inline]
 #0: ffff888012092420 (sb_writers#13){.+.+}-{0:0}, at: vfs_writev+0x2d1/0xba0 fs/read_write.c:1062
 #1: ffff88805be095f0 (&sb->s_type->i_mutex_key#21){++++}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
 #1: ffff88805be095f0 (&sb->s_type->i_mutex_key#21){++++}-{3:3}, at: exfat_file_write_iter+0x9e/0x3f0 fs/exfat/file.c:579
 #2: ffff8880120900e8 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_get_block+0x1c3/0x2180 fs/exfat/inode.c:278
2 locks held by kworker/u8:10/7308:
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90004487d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90004487d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
2 locks held by syz-executor/8183:
2 locks held by syz.8.314/8667:
1 lock held by kworker/u8:10/8682:
1 lock held by syz.3.317/8690:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-rc6-syzkaller-00272-gda4373fbcf00 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7016 Comm: syz.5.142 Not tainted 6.12.0-rc6-syzkaller-00272-gda4373fbcf00 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:__this_cpu_preempt_check+0x0/0x20 lib/smp_processor_id.c:65
Code: d1 fc ff e8 02 7d ff ff eb a8 e8 4b e0 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 89 fe 48 c7 c7 e0 35 60 8c e9 bd fe ff ff 66 2e 0f
RSP: 0018:ffffc9000331f3b8 EFLAGS: 00000082
RAX: ffffffff821fe4c4 RBX: 00000000000000cc RCX: 0000000000040000
RDX: ffffc900168d8000 RSI: 000000000003ffff RDI: ffffffff8c198140
RBP: ffffc9000331f4f0 R08: ffffffff821fe51d R09: 1ffffffff347cd7c
R10: dffffc0000000000 R11: fffffbfff347cd7d R12: ffff88805efae1d0
R13: 0000000000039958 R14: fffffffffffffffd R15: 00000000000000dc
FS:  00007f5e2aea06c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb5f588000 CR3: 0000000027480000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lookup_bh_lru fs/buffer.c:1371 [inline]
 __find_get_block+0x477/0x1150 fs/buffer.c:1400
 bdev_getblk+0x33/0x550 fs/buffer.c:1431
 __bread_gfp+0x86/0x400 fs/buffer.c:1491
 sb_bread include/linux/buffer_head.h:346 [inline]
 exfat_get_dentry+0x53b/0x730 fs/exfat/dir.c:691
 exfat_readdir fs/exfat/dir.c:121 [inline]
 exfat_iterate+0xb69/0x3390 fs/exfat/dir.c:261
 wrap_directory_iterator+0x91/0xd0 fs/readdir.c:65
 iterate_dir+0x571/0x800 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:407 [inline]
 __se_sys_getdents64+0x1d3/0x4a0 fs/readdir.c:392
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5e2a17e719
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5e2aea0038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f5e2a335f80 RCX: 00007f5e2a17e719
RDX: 0000000000001000 RSI: 0000000020000f80 RDI: 0000000000000006
RBP: 00007f5e2a1f139e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5e2a335f80 R15: 00007ffef5944d68
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/09 20:46 upstream da4373fbcf00 6b856513 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in exfat_get_block
* Struck through repros no longer work on HEAD.