syzbot
INFO: task hung in netfs_read_folio
Status: auto-obsoleted due to no activity on 2026/09/28 10:18
Subsystems:
fs
mm
[Documentation on labels]
First crash: 112d, last: 112d
Sample crash report:
INFO: task syz.0.4813:5058 blocked in I/O wait for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.4813 state:D stack:25568 pid:5058 tgid:5052 ppid:4532 task_flags:0x400140 flags:0x08080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
io_schedule+0x8a/0xf0 kernel/sched/core.c:8154
folio_wait_bit_common+0x414/0xa70 mm/filemap.c:1323
folio_wait_writeback+0x92/0x130 mm/page-writeback.c:3068
netfs_read_folio+0x67/0x13f0 fs/netfs/buffered_read.c:506
filemap_read_folio+0xfc/0x3b0 mm/filemap.c:2510
filemap_update_page mm/filemap.c:2597 [inline]
filemap_get_pages+0x173d/0x2030 mm/filemap.c:2727
filemap_read+0x3b5/0x10a0 mm/filemap.c:2814
netfs_buffered_read_iter+0x12a/0x190 fs/netfs/buffered_read.c:800
netfs_file_read_iter+0x10f/0x190 fs/netfs/buffered_read.c:836
v9fs_file_read_iter+0x9b/0x100 fs/9p/vfs_file.c:369
__kernel_read+0x397/0xad0 fs/read_write.c:532
integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
security_file_post_open+0xc4/0x210 security/security.c:2755
do_open fs/namei.c:4702 [inline]
path_openat+0x985/0x4280 fs/namei.c:4859
do_file_open+0x20e/0x430 fs/namei.c:4888
do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_compat_sys_open fs/open.c:1427 [inline]
__se_compat_sys_open fs/open.c:1425 [inline]
__ia32_compat_sys_open+0xfe/0x1c0 fs/open.c:1425
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307
do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf704efec
RSP: 002b:00000000f541c50c EFLAGS: 00000292 ORIG_RAX: 0000000000000005
RAX: ffffffffffffffda RBX: 0000000080000140 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Showing all locks held in the system:
3 locks held by kworker/u32:0/12:
#0: ffff88801ce8c940 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc900001e7d08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffffffff906288e8 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:673
1 lock held by khungtaskd/43:
#0: ffffffff8e7e5ec0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e7e5ec0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e7e5ec0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
6 locks held by kworker/1:1/50:
#0: ffff8880214b4540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000071fd08 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffff888023b581d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#2: ffff888023b581d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
#3: ffff888022a311d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#3: ffff888022a311d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#4: ffff8880667ac1a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#4: ffff8880667ac1a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
#5: ffff888053184668 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
#5: ffff888053184668 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
3 locks held by kworker/3:2/860:
#0: ffff88801b8aa940 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc90004007d08 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffffffff8e7f1968 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by getty/5544:
#0: ffff88802a6e40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000019b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
3 locks held by sshd-session/5728:
4 locks held by kworker/u33:31/13510:
#0: ffff88801df27940 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000427fd08 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffff88804e3500d8 (&type->s_umount_key#57){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:566
#3: ffff888012f096f8 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xba/0x990 fs/netfs/write_issue.c:554
1 lock held by syz.6.4298/1117:
#0: ffffffff90641500 (rtnl_mutex){+.+.}-{4:4}, at: ppp_release+0xab/0x150 drivers/net/ppp/ppp_generic.c:413
1 lock held by syz.4.4599/3318:
#0: ffffffff8e7f1968 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by kworker/u33:5/3596:
#0: ffff888022a60940 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000cfb7d08 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
3 locks held by syz.0.4813/5058:
#0: ffff888024978378 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}, at: process_measurement+0x5ab/0x2350 security/integrity/ima/ima_main.c:319
#1: ffff888012f09388 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: netfs_start_io_read+0x1f/0x100 fs/netfs/locking.c:62
#2: ffff888012f09520 (mapping.invalidate_lock#4){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#2: ffff888012f09520 (mapping.invalidate_lock#4){.+.+}-{4:4}, at: filemap_update_page mm/filemap.c:2563 [inline]
#2: ffff888012f09520 (mapping.invalidate_lock#4){.+.+}-{4:4}, at: filemap_get_pages+0x123e/0x2030 mm/filemap.c:2727
4 locks held by udevd/6331:
#0: ffff888051f8ef38 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1: ffff888058090c80 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165
#2: ffff88804bec70f8 (kn->active#16){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff88804bec70f8 (kn->active#16){.+.+}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:166
#3: ffff888022a311d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1107 [inline]
#3: ffff888022a311d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
3 locks held by syz.3.5290/8309:
=============================================
NMI backtrace for cpu 3
CPU: 3 UID: 0 PID: 43 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Sending NMI from CPU 3 to CPUs 0-2:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 8309 Comm: syz.3.5290 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__nr_to_section+0x1a/0x100 include/linux/mmzone.h:2050
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 54 55 53 48 89 fb 49 89 dc 49 c1 ec 07 e8 2d 7a 84 ff e9 a5 00 00 00 31 ed <e8> 21 7a 84 ff 40 80 fd 01 4c 89 e6 48 19 ed 81 e5 00 f0 03 00 48
RSP: 0018:ffffc9000339f7c0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 000000000000000b RCX: ffffffff8284958a
RDX: ffff8880291b2540 RSI: ffffffff82846213 RDI: 000000000000000b
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: ffffea00016490c0 R14: ffffea00016490f4 R15: ffffea00016490c0
FS: 0000000000000000(0000) GS:ffff8880971e7000(0000) knlGS:0000000000000000
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00007fa7b53663b0 CR3: 000000000e592000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__pfn_to_section include/linux/mmzone.h:2187 [inline]
lookup_page_ext+0x46/0x100 mm/page_ext.c:255
page_ext_iter_begin include/linux/page_ext.h:133 [inline]
__page_table_check_zero+0xe1/0x410 mm/page_table_check.c:139
page_table_check_free include/linux/page_table_check.h:46 [inline]
__free_pages_prepare mm/page_alloc.c:1407 [inline]
free_pages_prepare+0x576/0xd80 mm/page_alloc.c:1451
__free_contig_range_common+0x14f/0x250 mm/page_alloc.c:6897
__free_contig_range mm/page_alloc.c:6942 [inline]
free_pages_bulk+0xbd/0x200 mm/page_alloc.c:5257
vm_area_free_pages+0xad/0x2b0 mm/vmalloc.c:3439
vfree mm/vmalloc.c:3488 [inline]
vfree+0x107/0x750 mm/vmalloc.c:3462
kcov_put kernel/kcov.c:447 [inline]
kcov_put kernel/kcov.c:443 [inline]
kcov_close+0x34/0x60 kernel/kcov.c:554
__fput+0x3ff/0xb50 fs/file_table.c:512
task_work_run+0x150/0x240 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x951/0x2ae0 kernel/exit.c:1004
do_group_exit+0xd5/0x2a0 kernel/exit.c:1147
get_signal+0x1ec7/0x21e0 kernel/signal.c:3038
arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
__do_fast_syscall_32+0x701/0x970 arch/x86/entry/syscall_32.c:310
do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf6ffefec
Code: Unable to access opcode bytes at 0xf6ffefc2.
RSP: 002b:00000000f53cc50c EFLAGS: 00000292 ORIG_RAX: 0000000000000151
RAX: 0000000000010106 RBX: 0000000000000005 RCX: 00000000800000c0
RDX: 0000000000010106 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: d6 86 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d c3 57 11 00 fb f4 <e9> bc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e407e10 EFLAGS: 00000206
RAX: 00000000024531bb RBX: ffffffff8e491480 RCX: ffffffff8b9a42d5
RDX: 0000000000000000 RSI: ffffffff8df5902e RDI: ffffffff8c1e8f80
RBP: fffffbfff1c92290 R08: 0000000000000001 R09: ffffed100564678d
R10: ffff88802b233c6b R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffffffff1c80fc6 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880970e7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000081000000 CR3: 000000000e592000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000000f010e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:768
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
rest_init+0x251/0x260 init/main.c:717
start_kernel+0x48e/0x490 init/main.c:1175
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x158
</TASK>
NMI backtrace for cpu 2
CPU: 2 UID: 0 PID: 0 Comm: swapper/2 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: d6 86 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d c3 57 11 00 fb f4 <e9> bc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc9000047fe00 EFLAGS: 00000206
RAX: 0000000001632be7 RBX: ffff88801c7e4a80 RCX: ffffffff8b9a42d5
RDX: 0000000000000000 RSI: ffffffff8df5902e RDI: ffffffff8c1e8f80
RBP: ffffed10038fc950 R08: 0000000000000001 R09: ffffed100568678d
R10: ffff88802b433c6b R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffff9200008ffc4 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880972e7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ca3c17a000 CR3: 0000000022183000 CR4: 0000000000352ef0
Call Trace:
<TASK>
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:768
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x158
</TASK>
Struck through repros no longer work on HEAD.