syzbot

INFO: task udevd:4591 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:22512 pid:4591  ppid:3639   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8798
 folio_wait_bit_common+0x70a/0xfa0 mm/filemap.c:1324
 folio_put_wait_locked mm/filemap.c:1493 [inline]
 do_read_cache_folio+0x1a9/0x760 mm/filemap.c:3641
 read_mapping_folio include/linux/pagemap.h:799 [inline]
 read_part_sector+0xce/0x350 block/partitions/core.c:724
 adfspart_check_POWERTEC+0xc0/0x890 block/partitions/acorn.c:454
 check_partition block/partitions/core.c:146 [inline]
 blk_add_partitions block/partitions/core.c:609 [inline]
 bdev_disk_changed+0x7d9/0x14a0 block/partitions/core.c:695
 blkdev_get_whole+0x2e8/0x370 block/bdev.c:704
 blkdev_get_by_dev+0x32e/0xa60 block/bdev.c:841
 blkdev_open+0x11e/0x2e0 block/fops.c:500
 do_dentry_open+0x7e9/0x10d0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x2635/0x2ee0 fs/namei.c:3791
 do_filp_open+0x1f1/0x430 fs/namei.c:3818
 do_sys_openat2+0x150/0x4b0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f04274a7407
RSP: 002b:00007fff2e2423d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0427b69880 RCX: 00007f04274a7407
RDX: 00000000000a0800 RSI: 000055ba61054860 RDI: ffffffffffffff9c
RBP: 000055ba61048910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055ba6105be20
R13: 000055ba61060410 R14: 0000000000000000 R15: 000055ba6105be20
 </TASK>
INFO: task udevd:4914 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:24720 pid:4914  ppid:3639   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8798
 folio_wait_bit_common+0x70a/0xfa0 mm/filemap.c:1324
 folio_put_wait_locked mm/filemap.c:1493 [inline]
 do_read_cache_folio+0x1a9/0x760 mm/filemap.c:3641
 read_mapping_folio include/linux/pagemap.h:799 [inline]
 read_part_sector+0xce/0x350 block/partitions/core.c:724
 adfspart_check_POWERTEC+0xc0/0x890 block/partitions/acorn.c:454
 check_partition block/partitions/core.c:146 [inline]
 blk_add_partitions block/partitions/core.c:609 [inline]
 bdev_disk_changed+0x7d9/0x14a0 block/partitions/core.c:695
 blkdev_get_whole+0x2e8/0x370 block/bdev.c:704
 blkdev_get_by_dev+0x32e/0xa60 block/bdev.c:841
 blkdev_open+0x11e/0x2e0 block/fops.c:500
 do_dentry_open+0x7e9/0x10d0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x2635/0x2ee0 fs/namei.c:3791
 do_filp_open+0x1f1/0x430 fs/namei.c:3818
 do_sys_openat2+0x150/0x4b0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f04274a7407
RSP: 002b:00007fff2e2423d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0427b69880 RCX: 00007f04274a7407
RDX: 00000000000a0800 RSI: 000055ba61070920 RDI: ffffffffffffff9c
RBP: 000055ba61048910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055ba6106db40
R13: 000055ba61060410 R14: 0000000000000000 R15: 000055ba6106db40
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2dfb0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2e7d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4031:
 #0: ffff88802fa1b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198
1 lock held by udevd/4591:
 #0: ffff8880243364c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
3 locks held by kworker/0:18/4831:
 #0: ffff8880b8e3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:538
 #1: ffff8880b8e27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999
 #2: ffff8880b8e28458 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
1 lock held by udevd/4914:
 #0: ffff8881443de4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
2 locks held by syz.4.3331/14916:
1 lock held by dhcpcd-run-hook/14915:

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 14915 Comm: dhcpcd-run-hook Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__lock_acquire+0x19ee/0x7d10 kernel/locking/lockdep.c:5072
Code: 37 48 8b 44 24 70 42 0f b6 04 00 84 c0 0f 85 44 52 00 00 8b 03 ff c0 89 03 83 f8 30 0f 83 c5 40 00 00 c7 44 24 34 01 00 00 00 <3b> 05 fc d7 4a 0f 0f 86 50 40 00 00 89 05 f0 d7 4a 0f e9 45 40 00
RSP: 0000:ffffc9000d057660 EFLAGS: 00000087
RAX: 0000000000000004 RBX: ffff888019f4e418 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90af3240
RBP: ffffc9000d0578b0 R08: dffffc0000000000 R09: 1ffffffff215e648
R10: dffffc0000000000 R11: fffffbfff215e649 R12: 2931d50f634288da
R13: 0000000069159a9e R14: 2931d50f634288da R15: ffff888019f4e410
FS:  00007fbcb3013c80(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbcb332ffeb CR3: 00000000788aa000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock_sched include/linux/rcupdate.h:883 [inline]
 pfn_valid+0xe9/0x420 include/linux/mmzone.h:1857
 page_table_check_set+0x25/0x6d0 mm/page_table_check.c:108
 page_table_check_pte_set include/linux/page_table_check.h:83 [inline]
 set_pte_at arch/x86/include/asm/pgtable.h:1009 [inline]
 do_set_pte+0x452/0x460 mm/memory.c:4424
 filemap_map_pages+0xc8b/0x11c0 mm/filemap.c:3513
 do_fault_around mm/memory.c:4598 [inline]
 do_read_fault mm/memory.c:4624 [inline]
 do_fault mm/memory.c:4758 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x2991/0x3ee0 mm/memory.c:5292
 do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340
 handle_page_fault arch/x86/mm/fault.c:1431 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7fbcb332ffeb
Code: Unable to access opcode bytes at 0x7fbcb332ffc1.
RSP: 002b:00007ffc5273c9e8 EFLAGS: 00010287
RAX: 00007fbcb337a190 RBX: 000055df16499910 RCX: 0000000000000002
RDX: 000055df16499910 RSI: 000055df164a2030 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000020
R10: 0000000000000040 R11: 0000000000000000 R12: 000055df164a1d60
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
 </TASK>