syzbot


INFO: task hung in find_inode_fast (2)

Status: upstream: reported on 2024/11/01 11:14
Reported-by: syzbot+0cc7a1e9176813931db6@syzkaller.appspotmail.com
First crash: 35d, last: 35d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in find_inode_fast (3) ext4 7 116d 214d 0/28 auto-obsoleted due to no activity on 2024/11/10 11:05
upstream INFO: task hung in find_inode_fast (2) ext4 C unreliable done 10 358d 512d 25/28 fixed on 2024/01/30 15:47
linux-5.15 INFO: task hung in find_inode_fast 3 575d 594d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:07
upstream INFO: task hung in find_inode_fast ext4 C error 28 549d 698d 22/28 fixed on 2023/06/08 14:41
linux-6.1 INFO: task hung in find_inode_fast 1 16d 16d 0/3 upstream: reported on 2024/11/20 14:47

Sample crash report:
INFO: task syz.4.788:7634 blocked for more than 143 seconds.
      Not tainted 5.15.170-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.788       state:D stack:23392 pid: 7634 ppid:  4176 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 __wait_on_freeing_inode fs/inode.c:2114 [inline]
 find_inode_fast+0x315/0x450 fs/inode.c:908
 iget_locked+0xb2/0x7f0 fs/inode.c:1270
 __ext4_iget+0x25d/0x3f00 fs/ext4/inode.c:4648
 ext4_xattr_inode_cache_find fs/ext4/xattr.c:1499 [inline]
 ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1534 [inline]
 ext4_xattr_set_entry+0x22cd/0x4040 fs/ext4/xattr.c:1675
 ext4_xattr_block_set+0xb10/0x36a0 fs/ext4/xattr.c:1995
 ext4_xattr_set_handle+0xdac/0x1560 fs/ext4/xattr.c:2412
 ext4_xattr_set+0x26e/0x3d0 fs/ext4/xattr.c:2513
 __vfs_setxattr+0x3e7/0x420 fs/xattr.c:182
 __vfs_setxattr_noperm+0x12a/0x5e0 fs/xattr.c:216
 vfs_setxattr+0x21d/0x420 fs/xattr.c:303
 do_setxattr fs/xattr.c:588 [inline]
 setxattr+0x27e/0x2e0 fs/xattr.c:611
 path_setxattr+0x1bc/0x2a0 fs/xattr.c:630
 __do_sys_setxattr fs/xattr.c:646 [inline]
 __se_sys_setxattr fs/xattr.c:642 [inline]
 __x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:642
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f0e086a2719
RSP: 002b:00007f0e06b1a038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f0e08859f80 RCX: 00007f0e086a2719
RDX: 0000000020001400 RSI: 00000000200001c0 RDI: 0000000020000200
RBP: 00007f0e0871532e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000835 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0e08859f80 R15: 00007ffe823dca58
 </TASK>
INFO: task syz.4.788:7662 blocked for more than 144 seconds.
      Not tainted 5.15.170-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.788       state:D stack:24504 pid: 7662 ppid:  4176 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 mb_cache_entry_wait_unused+0x164/0x240 fs/mbcache.c:148
 ext4_evict_ea_inode+0x146/0x2e0 fs/ext4/xattr.c:444
 ext4_evict_inode+0x17d/0x1100 fs/ext4/inode.c:183
 evict+0x529/0x930 fs/inode.c:622
 ext4_xattr_inode_array_free+0x77/0xf0 fs/ext4/xattr.c:2984
 ext4_evict_inode+0xdfc/0x1100 fs/ext4/inode.c:338
 evict+0x529/0x930 fs/inode.c:622
 do_unlinkat+0x508/0x950 fs/namei.c:4355
 __do_sys_unlink fs/namei.c:4396 [inline]
 __se_sys_unlink fs/namei.c:4394 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4394
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f0e086a2719
RSP: 002b:00007f0e06ad8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007f0e0885a130 RCX: 00007f0e086a2719
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000f40
RBP: 00007f0e0871532e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f0e0885a130 R15: 00007ffe823dca58
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
 #0: ffff8880171cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc9000174fd20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8c924130 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x9c/0x4e0 kernel/rcu/tree.c:4039
 #3: ffff8880b903a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
2 locks held by getty/3922:
 #0: ffff88814cb58098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025ae2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
2 locks held by kworker/0:4/4208:
 #0: ffff888017072138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90003147d20 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
3 locks held by syz.4.788/7634:
 #0: ffff8880252e6460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
 #1: ffff888063d567a0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #1: ffff888063d567a0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_setxattr+0x1dd/0x420 fs/xattr.c:302
 #2: ffff888063d56478 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
 #2: ffff888063d56478 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x270/0x1560 fs/ext4/xattr.c:2327
1 lock held by syz.4.788/7662:
 #0: ffff8880252e6460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
2 locks held by dhcpcd/12134:
 #0: ffff888063cad010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #0: ffff888063cad010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:648 [inline]
 #0: ffff888063cad010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1336
 #1: ffffffff8c924228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8c924228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x280/0x740 kernel/rcu/tree_exp.h:845
1 lock held by syz.6.2157/13129:
 #0: ffffffff8c924130 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x9c/0x4e0 kernel/rcu/tree.c:4039
1 lock held by dhcpcd-run-hook/13146:

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.170-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4207 Comm: kworker/1:5 Not tainted 5.15.170-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events bpf_prog_free_deferred
RIP: 0010:unwind_next_frame+0x451/0x1fa0
Code: c1 e8 03 0f b6 04 10 84 c0 0f 85 49 14 00 00 0f b7 45 00 89 c3 83 e3 0f 0f 84 9b 00 00 00 8d 43 fe 83 f8 07 0f 87 29 01 00 00 <48> 89 6c 24 18 ff 24 c5 60 8f 88 8a 48 8b 44 24 30 80 3c 10 00 48
RSP: 0018:ffffc90003137448 EFLAGS: 00000297
RAX: 0000000000000003 RBX: 0000000000000005 RCX: ffffffff8df7732c
RDX: dffffc0000000000 RSI: ffffffff8e5fcbe4 RDI: ffffffff8df77308
RBP: ffffffff8e5fcc18 R08: 0000000000000009 R09: ffffc90003137560
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff1cbf983
R13: ffffffff8138ba8e R14: ffffffff8e5fcc14 R15: ffffc90003137560
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555cac8ba131 CR3: 0000000023684000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __unwind_start+0x59d/0x720 arch/x86/kernel/unwind_orc.c:704
 unwind_start arch/x86/include/asm/unwind.h:60 [inline]
 arch_stack_walk+0xdb/0x140 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x80 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kmem_cache_free+0x91/0x1f0 mm/slub.c:3515
 merge_or_add_vmap_area mm/vmalloc.c:1111 [inline]
 merge_or_add_vmap_area_augment mm/vmalloc.c:1161 [inline]
 __purge_vmap_area_lazy+0x548/0x1740 mm/vmalloc.c:1697
 _vm_unmap_aliases+0x453/0x4e0 mm/vmalloc.c:2107
 vm_remove_mappings mm/vmalloc.c:2584 [inline]
 __vunmap+0x72e/0xa20 mm/vmalloc.c:2611
 bpf_jit_binary_free kernel/bpf/core.c:914 [inline]
 bpf_jit_free+0x92/0x180 kernel/bpf/core.c:927
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/01 11:14 linux-5.15.y 72244eab0dad 96eb609f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in find_inode_fast
* Struck through repros no longer work on HEAD.