syzbot

INFO: task udevd:5792 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:24136 pid:5792  ppid:5157   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 io_schedule+0x80/0xd0 kernel/sched/core.c:9022
 folio_wait_bit_common+0x6eb/0xf70 mm/filemap.c:1329
 folio_put_wait_locked mm/filemap.c:1493 [inline]
 do_read_cache_folio+0x1c0/0x7e0 mm/filemap.c:3771
 read_mapping_folio include/linux/pagemap.h:898 [inline]
 read_part_sector+0xd2/0x350 block/partitions/core.c:718
 adfspart_check_POWERTEC+0x8d/0xf00 block/partitions/acorn.c:454
 check_partition block/partitions/core.c:138 [inline]
 blk_add_partitions block/partitions/core.c:600 [inline]
 bdev_disk_changed+0x73a/0x1410 block/partitions/core.c:689
 blkdev_get_whole+0x30d/0x390 block/bdev.c:655
 blkdev_get_by_dev+0x279/0x600 block/bdev.c:797
 blkdev_open+0x152/0x360 block/fops.c:589
 do_dentry_open+0x8c6/0x1500 fs/open.c:929
 do_open fs/namei.c:3632 [inline]
 path_openat+0x274b/0x3190 fs/namei.c:3789
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
 do_sys_open fs/open.c:1434 [inline]
 __do_sys_openat fs/open.c:1450 [inline]
 __se_sys_openat fs/open.c:1445 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1445
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8752ca7407
RSP: 002b:00007ffdff4ebad0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f8753488880 RCX: 00007f8752ca7407
RDX: 00000000000a0800 RSI: 000055c7ec8404d0 RDI: ffffffffffffff9c
RBP: 000055c7ec83f910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055c7ec859320
R13: 000055c7ec857410 R14: 0000000000000000 R15: 000055c7ec859320
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
4 locks held by kworker/u4:6/1150:
2 locks held by getty/5555:
 #0: ffff88802ce4c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
1 lock held by udevd/5792:
 #0: ffff888021d2f4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:788

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf41/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5146 Comm: klogd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:vsnprintf+0x124e/0x1a40 lib/vsprintf.c:2773
Code: 4c 8b 64 24 18 4c 89 ef 4c 89 e6 48 89 d9 e8 99 2f 00 00 49 89 c5 48 89 e8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 1a 01 00 00 <80> 7d 00 00 0f 84 cd 06 00 00 e8 d3 d7 26 f7 49 89 ef e9 78 ee ff
RSP: 0018:ffffc90003247838 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff0a0000000500 RCX: 000000000000002e
RDX: 0000000000000000 RSI: ffffffff8aab7b85 RDI: ffffc90003247b09
RBP: ffffffff8aab7b86 R08: ffffc90003247b09 R09: 1ffff92000648f61
R10: dffffc0000000000 R11: fffff52000648f62 R12: ffffc90083247b02
R13: ffffc90003247b0a R14: dffffc0000000000 R15: ffffffff8aab7b85
FS:  00007f90f972dc80(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555594870608 CR3: 000000002dc89000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 sprintf+0xda/0x120 lib/vsprintf.c:3027
 print_time kernel/printk/printk.c:1327 [inline]
 info_print_prefix+0x156/0x300 kernel/printk/printk.c:1353
 record_print_text+0x155/0x420 kernel/printk/printk.c:1402
 syslog_print+0x36a/0x590 kernel/printk/printk.c:1613
 do_syslog+0x576/0x7f0 kernel/printk/printk.c:1732
 __do_sys_syslog kernel/printk/printk.c:1824 [inline]
 __se_sys_syslog kernel/printk/printk.c:1822 [inline]
 __x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1822
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f90f98f7a37
Code: 73 01 c3 48 8b 0d c1 f3 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 67 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 91 f3 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007fff4ce08338 EFLAGS: 00000206 ORIG_RAX: 0000000000000067
RAX: ffffffffffffffda RBX: 00007f90f9a97490 RCX: 00007f90f98f7a37
RDX: 00000000000003ff RSI: 00007f90f9a97490 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000206 R12: 00007f90f9a97490
R13: 00007f90f9a74dfe R14: 00007f90f9a9750e R15: 00007f90f9a9750e
 </TASK>