syzbot

INFO: task udevd:11351 blocked for more than 122 seconds.
      Not tainted 6.12.30-syzkaller-g030e00a2d78c #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:0     pid:11351 tgid:11351 ppid:109    flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5924 [inline]
 __schedule+0x145b/0x1f10 kernel/sched/core.c:7750
 __schedule_loop kernel/sched/core.c:7831 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7846
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7903
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0x836/0x1b60 kernel/locking/mutex.c:786
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1117
 mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:270
 bdev_open+0xd5/0xd60 block/bdev.c:909
 blkdev_open+0x3d1/0x560 block/fops.c:627
 do_dentry_open+0x978/0x1510 fs/open.c:960
 vfs_open+0x86/0x230 fs/open.c:1090
 do_open fs/namei.c:3774 [inline]
 path_openat+0x2b6c/0x34b0 fs/namei.c:3933
 do_filp_open+0x1c6/0x3e0 fs/namei.c:3960
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1438
 do_sys_open fs/open.c:1453 [inline]
 __do_sys_openat fs/open.c:1469 [inline]
 __se_sys_openat fs/open.c:1464 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1464
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f1ef8aa7407
RSP: 002b:00007ffcf35c1260 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f1ef9292880 RCX: 00007f1ef8aa7407
RDX: 00000000000a0800 RSI: 00005646a0172fa0 RDI: ffffffffffffff9c
RBP: 000056469ff392c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005646a017f380
R13: 00005646a017e990 R14: 0000000000000000 R15: 00005646a017f380
 </TASK>
INFO: task syz.4.6070:12542 blocked for more than 123 seconds.
      Not tainted 6.12.30-syzkaller-g030e00a2d78c #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.6070      state:D stack:0     pid:12542 tgid:12541 ppid:11384  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5924 [inline]
 __schedule+0x145b/0x1f10 kernel/sched/core.c:7750
 __schedule_loop kernel/sched/core.c:7831 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7846
 io_schedule+0x89/0xe0 kernel/sched/core.c:8658
 folio_wait_bit_common+0x6ae/0x910 mm/filemap.c:1336
 folio_put_wait_locked mm/filemap.c:1500 [inline]
 do_read_cache_folio+0x14d/0x4d0 mm/filemap.c:3880
 read_cache_folio+0x54/0x90 mm/filemap.c:3930
 read_mapping_folio include/linux/pagemap.h:1019 [inline]
 read_part_sector+0xcc/0x250 block/partitions/core.c:716
 msdos_partition+0x118/0x3000 block/partitions/msdos.c:592
 check_partition block/partitions/core.c:138 [inline]
 blk_add_partitions block/partitions/core.c:583 [inline]
 bdev_disk_changed+0x819/0x1610 block/partitions/core.c:687
 loop_reread_partitions+0x64/0x110 drivers/block/loop.c:464
 loop_configure+0xfd8/0x1320 drivers/block/loop.c:1071
 lo_ioctl+0x76c/0x20a0 drivers/block/loop.c:-1
 blkdev_ioctl+0x546/0x680 block/ioctl.c:693
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0x132/0x1b0 fs/ioctl.c:893
 __x64_sys_ioctl+0x7f/0xa0 fs/ioctl.c:893
 x64_sys_call+0x1878/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f39add8e929
RSP: 002b:00007f39aec7b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f39adfb5fa0 RCX: 00007f39add8e929
RDX: 00002000000002c0 RSI: 0000000000004c0a RDI: 0000000000000003
RBP: 00007f39ade10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f39adfb5fa0 R15: 00007fff3d1209c8
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.30-syzkaller-g030e00a2d78c #0 57efd5a98e1182d97bd5f975427dc401009108c9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:229 [inline]
 watchdog+0xd8f/0xed0 kernel/hung_task.c:385
 kthread+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 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: 0 Comm: swapper/0 Not tainted 6.12.30-syzkaller-g030e00a2d78c #0 57efd5a98e1182d97bd5f975427dc401009108c9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pv_native_safe_halt+0x17/0x20 arch/x86/kernel/paravirt.c:106
Code: cc cc cc b8 4b 49 db cc 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 73 dc 41 00 f3 0f 1e fa 55 48 89 e5 fb f4 <5d> e9 c3 59 02 00 cc cc cc b8 00 00 00 00 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff87207da0 EFLAGS: 000002c6
RAX: ffff8881f6e00000 RBX: ffffffff87215540 RCX: ffffffff8585700e
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 00000000002fb8ac
RBP: ffffffff87207da0 R08: ffff8881f6e39733 R09: 1ffff1103edc72e6
R10: dffffc0000000000 R11: ffffed103edc72e7 R12: 1ffffffff0e42aa8
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff87ca6f28
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b89402ab98 CR3: 000000010b380000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline]
 default_idle+0x17/0x30 arch/x86/kernel/process.c:748
 arch_cpu_idle+0xd/0x20 arch/x86/kernel/process.c:785
 default_idle_call+0x3f/0x80 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1a0/0x470 kernel/sched/idle.c:326
 cpu_startup_entry+0x48/0x70 kernel/sched/idle.c:424
 rest_init+0x10b/0x130 init/main.c:748
 start_kernel+0x46a/0x4bb init/main.c:1135
 x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:507
 x86_64_start_kernel+0x6a/0x7b arch/x86/kernel/head64.c:488
 common_startup_64+0x13b/0x157
 </TASK>