syzbot


INFO: task hung in __fscache_acquire_volume (2)

Status: auto-obsoleted due to no activity on 2025/05/10 07:00
Subsystems: netfs
[Documentation on labels]
First crash: 92d, last: 92d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in __fscache_acquire_volume netfs 1 309d 309d 0/28 auto-obsoleted due to no activity on 2024/10/05 05:45

Sample crash report:
INFO: task syz.0.1813:12102 blocked for more than 144 seconds.
      Not tainted 6.14.0-rc1-syzkaller-00235-g9946eaf552b1 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1813      state:D stack:26320 pid:12102 tgid:12101 ppid:5827   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6856
 bit_wait+0x12/0xd0 kernel/sched/wait_bit.c:237
 __wait_on_bit+0xb0/0x2f0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x1d5/0x260 kernel/sched/wait_bit.c:64
 wait_on_bit include/linux/wait_bit.h:77 [inline]
 fscache_wait_on_volume_collision fs/netfs/fscache_volume.c:163 [inline]
 fscache_hash_volume fs/netfs/fscache_volume.c:200 [inline]
 __fscache_acquire_volume+0xbe2/0xe20 fs/netfs/fscache_volume.c:343
 fscache_acquire_volume include/linux/fscache.h:207 [inline]
 v9fs_cache_session_get_cookie+0x121/0x1c0 fs/9p/cache.c:34
 v9fs_session_init+0x176d/0x1b80 fs/9p/v9fs.c:475
 v9fs_mount+0xd5/0xa90 fs/9p/vfs_super.c:122
 legacy_get_tree+0xee/0x190 fs/fs_context.c:662
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3560
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
 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: 0033:0x7f360998cde9
RSP: 002b:00007f360a829038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f3609ba5fa0 RCX: 00007f360998cde9
RDX: 0000400000000040 RSI: 0000400000000000 RDI: 0000000000000000
RBP: 00007f3609a0e2a0 R08: 00004000000002c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3609ba5fa0 R15: 00007ffeacf73dd8
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_exp_gp_kthr/19:
1 lock held by khungtaskd/30:
 #0: ffffffff8e9387e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e9387e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e9387e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746
2 locks held by getty/5581:
 #0: ffff8880314860a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
3 locks held by kworker/1:6/5875:
2 locks held by kworker/u8:21/6054:
1 lock held by syz.4.2339/13865:
 #0: ffffffff8e93db80 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3741
1 lock held by syz.5.2340/13871:
 #0: ffff888079f12608 (&sb->s_type->i_mutex_key#9){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:877 [inline]
 #0: ffff888079f12608 (&sb->s_type->i_mutex_key#9){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline]
 #0: ffff888079f12608 (&sb->s_type->i_mutex_key#9){+.+.}-{4:4}, at: sock_close+0x90/0x240 net/socket.c:1398

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.14.0-rc1-syzkaller-00235-g9946eaf552b1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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:236 [inline]
 watchdog+0x1058/0x10a0 kernel/hung_task.c:399
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 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: 35 Comm: kworker/u8:2 Not tainted 6.14.0-rc1-syzkaller-00235-g9946eaf552b1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__lock_acquire+0xcbf/0x2100 kernel/locking/lockdep.c:5201
Code: bf 00 00 00 00 00 fc ff df 48 0f a3 1d 2a 9c 91 12 0f 83 66 09 00 00 49 8d 9d e0 0a 00 00 48 89 d8 48 c1 e8 03 48 89 44 24 58 <80> 3c 38 00 74 12 48 89 df e8 e3 a4 88 00 48 bf 00 00 00 00 00 fc
RSP: 0018:ffffc90000ab7850 EFLAGS: 00000802
RAX: 1ffff110040d451c RBX: ffff8880206a28e0 RCX: ffffffff819acc04
RDX: 0000000000000000 RSI: 0000000000000008 RDI: dffffc0000000000
RBP: ffff8880206a2940 R08: ffffffff942c6847 R09: 1ffffffff2858d08
R10: dffffc0000000000 R11: fffffbfff2858d09 R12: ffff8880206a28d4
R13: ffff8880206a1e00 R14: 0000000000000000 R15: ffff8880206a2960
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f97d457b338 CR3: 0000000034fda000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 000000000000002b DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xec/0x610 net/batman-adv/network-coding.c:719
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/09 06:56 upstream 9946eaf552b1 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in __fscache_acquire_volume
* Struck through repros no longer work on HEAD.