syzbot


INFO: task hung in __bread_gfp

Status: auto-closed as invalid on 2019/02/22 10:29
Subsystems: exfat
[Documentation on labels]
Reported-by: syzbot+41f78d46e6ed1707e54a@syzkaller.appspotmail.com
First crash: 2163d, last: 2067d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in __bread_gfp (3) fs 1 850d 850d 0/26 auto-closed as invalid on 2022/02/04 04:37
android-49 INFO: task hung in __bread_gfp 2 2149d 2162d 0/3 auto-closed as invalid on 2019/02/22 14:34
upstream INFO: task hung in __bread_gfp (2) jfs 5 1384d 1391d 0/26 auto-closed as invalid on 2020/07/20 01:01
upstream INFO: task hung in __bread_gfp (4) reiserfs C error 3 375d 436d 0/26 auto-obsoleted due to no activity on 2023/07/25 23:59

Sample crash report:
netlink: 2 bytes leftover after parsing attributes in process `syz-executor5'.
syz-executor3 (21658): /proc/21655/oom_adj is deprecated, please use /proc/21655/oom_score_adj instead.
INFO: task syz-executor0:21631 blocked for more than 120 seconds.
      Not tainted 4.16.0+ #16
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D21608 21631   4519 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2848 [inline]
 __schedule+0x807/0x1e40 kernel/sched/core.c:3490
 schedule+0xef/0x430 kernel/sched/core.c:3549
 io_schedule+0x1c/0x70 kernel/sched/core.c:5169
 bit_wait_io+0x18/0x90 kernel/sched/wait_bit.c:207
 __wait_on_bit+0xb3/0x130 kernel/sched/wait_bit.c:48
 out_of_line_wait_on_bit+0x204/0x3a0 kernel/sched/wait_bit.c:63
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 __wait_on_buffer fs/buffer.c:118 [inline]
 wait_on_buffer include/linux/buffer_head.h:356 [inline]
 __bread_slow fs/buffer.c:1192 [inline]
 __bread_gfp+0x2bd/0x310 fs/buffer.c:1373
 sb_bread include/linux/buffer_head.h:309 [inline]
 fat12_ent_bread+0x14e/0x3d0 fs/fat/fatent.c:75
 fat_ent_read_block fs/fat/fatent.c:441 [inline]
 fat_alloc_clusters+0x8bf/0x16b0 fs/fat/fatent.c:489
 fat_add_cluster+0x72/0x140 fs/fat/inode.c:101
 __fat_get_block fs/fat/inode.c:148 [inline]
 fat_get_block+0x373/0xaf0 fs/fat/inode.c:177
 __block_write_begin_int+0x505/0x1ad0 fs/buffer.c:1981
 __block_write_begin fs/buffer.c:2031 [inline]
 block_write_begin+0xd2/0x350 fs/buffer.c:2090
 cont_write_begin+0x531/0x820 fs/buffer.c:2440
 fat_write_begin+0x8d/0x120 fs/fat/inode.c:223
 generic_perform_write+0x39a/0x6a0 mm/filemap.c:3138
 __generic_file_write_iter+0x3be/0x5e0 mm/filemap.c:3263
 generic_file_write_iter+0x430/0x850 mm/filemap.c:3291
 call_write_iter include/linux/fs.h:1784 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x5bc/0x880 fs/read_write.c:487
 vfs_write+0x1f8/0x560 fs/read_write.c:549
 ksys_write+0xf9/0x250 fs/read_write.c:598
 SYSC_write fs/read_write.c:610 [inline]
 SyS_write+0x24/0x30 fs/read_write.c:607
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x455259
RSP: 002b:00007f49a7784c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f49a77856d4 RCX: 0000000000455259
RDX: 0000000000000110 RSI: 0000000020000040 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000006bd R14: 00000000006fd258 R15: 0000000000000000

Showing all locks held in the system:
3 locks held by kworker/u4:0/6:
 #0: 00000000b4ac3211 ((wq_completion)"writeback"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline]
 #0: 00000000b4ac3211 ((wq_completion)"writeback"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000b4ac3211 ((wq_completion)"writeback"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000b4ac3211 ((wq_completion)"writeback"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
 #0: 00000000b4ac3211 ((wq_completion)"writeback"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000b4ac3211 ((wq_completion)"writeback"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000b4ac3211 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116
 #1: 0000000004137fd5 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120
 #2: 00000000531e87cb (&type->s_umount_key#69){++++}, at: trylock_super+0x22/0x110 fs/super.c:395
2 locks held by khungtaskd/888:
 #0: 000000000f5a608d (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0: 000000000f5a608d (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249
 #1: 0000000033a85867 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470
1 lock held by rsyslogd/4355:
 #0: 000000005c1e1d63 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 fs/file.c:766
2 locks held by getty/4445:
 #0: 00000000f2800a33 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000ad9b919b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4446:
 #0: 00000000fca83156 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000163e4a5e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4447:
 #0: 00000000dd8d83f6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 0000000040d762b8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4448:
 #0: 000000006c45f455 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000009a51f7a8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4449:
 #0: 00000000187ffc7c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000002b409ced (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4450:
 #0: 000000007c4783b0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000db9cfcba (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4451:
 #0: 00000000dbb4a656 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000d45af333 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
4 locks held by syz-executor0/21631:
 #0: 00000000a674510c (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 fs/file.c:766
 #1: 000000001d82e3d7 (sb_writers#20){.+.+}, at: file_start_write include/linux/fs.h:2712 [inline]
 #1: 000000001d82e3d7 (sb_writers#20){.+.+}, at: vfs_write+0x452/0x560 fs/read_write.c:548
 #2: 00000000a0298fef (&sb->s_type->i_mutex_key#17){++++}, at: inode_lock include/linux/fs.h:713 [inline]
 #2: 00000000a0298fef (&sb->s_type->i_mutex_key#17){++++}, at: generic_file_write_iter+0xe5/0x850 mm/filemap.c:3288
 #3: 00000000891d706f (&sbi->fat_lock){+.+.}, at: lock_fat fs/fat/fatent.c:278 [inline]
 #3: 00000000891d706f (&sbi->fat_lock){+.+.}, at: fat_alloc_clusters+0x1a4/0x16b0 fs/fat/fatent.c:473
2 locks held by syz-executor0/21663:
 #0: 000000001d82e3d7 (sb_writers#20){.+.+}, at: sb_start_write include/linux/fs.h:1550 [inline]
 #0: 000000001d82e3d7 (sb_writers#20){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386
 #1: 00000000a0298fef (&sb->s_type->i_mutex_key#17){++++}, at: inode_lock include/linux/fs.h:713 [inline]
 #1: 00000000a0298fef (&sb->s_type->i_mutex_key#17){++++}, at: do_truncate+0x197/0x2a0 fs/open.c:61
1 lock held by syz-executor0/21664:
 #0: 00000000a674510c (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 fs/file.c:766
1 lock held by syz-executor6/21649:
 #0: 00000000531e87cb (&type->s_umount_key#69){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:596
1 lock held by syz-executor6/21666:
 #0: 00000000531e87cb (&type->s_umount_key#69){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:596

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

NMI backtrace for cpu 1
CPU: 1 PID: 888 Comm: khungtaskd Not tainted 4.16.0+ #16
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x151/0x192 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:138 [inline]
 check_hung_task kernel/hung_task.c:132 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0xc10/0xf60 kernel/hung_task.c:249
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0+ #16
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:find_next_bit+0x1/0x130 lib/find_bit.c:73
RSP: 0018:ffff8801db007a50 EFLAGS: 00000006
RAX: 000000000000003a RBX: 000000010002f3ba RCX: ffffffff815c9f51
RDX: 000000000000003a RSI: 0000000000000040 RDI: ffff8801db0236d8
RBP: ffff8801db007aa0 R08: ffffed003b6046d1 R09: ffffed003b6046d0
R10: ffffed003b6046d0 R11: ffff8801db023683 R12: 0000000000000000
R13: 000000000000003a R14: 0000000000000040 R15: 000000010002f3be
FS:  0000000000000000(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000cb1000 CR3: 00000001b0c46000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 get_next_timer_interrupt+0x68/0x320 kernel/time/timer.c:1534
 tick_nohz_stop_sched_tick kernel/time/tick-sched.c:693 [inline]
 __tick_nohz_idle_enter+0xd3d/0x1710 kernel/time/tick-sched.c:918
 tick_nohz_irq_exit+0x66/0x80 kernel/time/tick-sched.c:971
 tick_irq_exit kernel/softirq.c:387 [inline]
 irq_exit+0x1bb/0x200 kernel/softirq.c:407
 scheduler_ipi+0x52b/0xa30 kernel/sched/core.c:1778
 smp_reschedule_interrupt+0xed/0x660 arch/x86/kernel/smp.c:277
 reschedule_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:886
 </IRQ>
RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
RSP: 0018:ffffffff88a07c38 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02
RAX: dffffc0000000000 RBX: 1ffffffff1140f8a RCX: 0000000000000000
RDX: 1ffffffff1162f80 RSI: 0000000000000001 RDI: ffffffff88b17c00
RBP: ffffffff88a07c38 R08: ffffffff88a752c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff88a07cf0 R14: ffffffff88b17bf0 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
 default_idle+0xc2/0x440 arch/x86/kernel/process.c:354
 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:345
 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
 cpuidle_idle_call kernel/sched/idle.c:151 [inline]
 do_idle+0x2f4/0x3c0 kernel/sched/idle.c:241
 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:346
 rest_init+0xe1/0xe4 init/main.c:437
 start_kernel+0x887/0x8ae init/main.c:717
 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:443
 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:424
 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242
Code: 7e 42 fe 48 8b 45 c8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 ac 29 7e fe eb b8 66 2e 0f 1f 84 00 00 00 00 00 55 <48> 89 e5 41 57 41 56 49 89 fe 41 55 49 89 f5 41 54 53 48 89 d3 

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/04/10 23:45 upstream c18bb396d3d2 8b8de427 .config console log report ci-upstream-kasan-gce-root
2018/04/03 11:06 upstream 642e7fd23353 676bd07e .config console log report ci-upstream-kasan-gce
2018/07/07 17:51 linux-next 526674536360 ab89aea9 .config console log report ci-upstream-linux-next-kasan-gce-root
2018/07/07 08:25 linux-next 526674536360 6c0c0099 .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.