syzbot

INFO: task udevd:6015 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc4-syzkaller-00147-gebd297a2affa #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:22184 pid:6015  tgid:6015  ppid:5187   task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 io_schedule+0x81/0xe0 kernel/sched/core.c:7742
 folio_wait_bit_common+0x6b0/0xb90 mm/filemap.c:1317
 folio_put_wait_locked mm/filemap.c:1481 [inline]
 do_read_cache_folio+0x1ae/0x590 mm/filemap.c:3867
 read_mapping_folio include/linux/pagemap.h:995 [inline]
 read_part_sector+0xb6/0x270 block/partitions/core.c:722
 adfspart_check_POWERTEC+0x8c/0xf30 block/partitions/acorn.c:454
 check_partition block/partitions/core.c:141 [inline]
 blk_add_partitions block/partitions/core.c:589 [inline]
 bdev_disk_changed+0x75c/0x14b0 block/partitions/core.c:693
 blkdev_get_whole+0x380/0x510 block/bdev.c:748
 bdev_open+0x31e/0xd30 block/bdev.c:957
 blkdev_open+0x3a8/0x510 block/fops.c:652
 do_dentry_open+0xdf0/0x1970 fs/open.c:956
 vfs_open+0x3b/0x340 fs/open.c:1086
 do_open fs/namei.c:3880 [inline]
 path_openat+0x2ee5/0x3830 fs/namei.c:4039
 do_filp_open+0x1fa/0x410 fs/namei.c:4066
 do_sys_openat2+0x121/0x1c0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_openat fs/open.c:1460 [inline]
 __se_sys_openat fs/open.c:1455 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1455
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fecf477b9a4
RSP: 002b:00007ffe7823ead0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000055a4edc8ce80 RCX: 00007fecf477b9a4
RDX: 00000000000a0800 RSI: 000055a4edc6d2b0 RDI: 00000000ffffff9c
RBP: 000055a4edc6d2b0 R08: 0000000000000001 R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800
R13: 000055a4edc83890 R14: 0000000000000001 R15: 000055a4edc6c910
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
2 locks held by getty/5563:
 #0: ffff8880347fa0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by udevd/6015:
 #0: ffff888024ec3358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc4-syzkaller-00147-gebd297a2affa #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:437
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 14290 Comm: syz.0.2717 Not tainted 6.15.0-rc4-syzkaller-00147-gebd297a2affa #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:separate_irq_context kernel/locking/lockdep.c:4704 [inline]
RIP: 0010:__lock_acquire+0x711/0xd20 kernel/locking/lockdep.c:5219
Code: 89 37 8b 9f e8 0a 00 00 48 85 db 89 44 24 08 0f 84 8c 00 00 00 83 fb 31 0f 83 f4 05 00 00 48 8d 04 9b 45 8b 67 20 8b 44 c5 f8 <44> 31 e0 25 00 60 00 00 31 c9 89 c2 f7 da 48 19 c9 49 09 ce 85 c0
RSP: 0018:ffffc9000f5a7278 EFLAGS: 00000087
RAX: 000000000004003a RBX: 0000000000000003 RCX: ffffffff931aab30
RDX: 0000000000000008 RSI: ffff888058f72968 RDI: ffff888058f71e00
RBP: ffff888058f728f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff822a8ead R12: 000000000002001a
R13: 0000000000000000 R14: 25f6100a94b00d26 R15: ffff888058f72968
FS:  0000000000000000(0000) GS:ffff888126200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b918c9e198 CR3: 0000000076de2000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock_sched include/linux/rcupdate.h:932 [inline]
 pfn_valid+0xe9/0x420 include/linux/mmzone.h:2117
 page_table_check_clear+0x21/0x6e0 mm/page_table_check.c:70
 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline]
 get_and_clear_full_ptes include/linux/pgtable.h:714 [inline]
 zap_present_folio_ptes mm/memory.c:1501 [inline]
 zap_present_ptes mm/memory.c:1586 [inline]
 do_zap_pte_range mm/memory.c:1687 [inline]
 zap_pte_range mm/memory.c:1731 [inline]
 zap_pmd_range mm/memory.c:1823 [inline]
 zap_pud_range mm/memory.c:1852 [inline]
 zap_p4d_range mm/memory.c:1873 [inline]
 unmap_page_range+0x30be/0x4210 mm/memory.c:1894
 unmap_vmas+0x25d/0x3c0 mm/memory.c:1984
 exit_mmap+0x245/0xba0 mm/mmap.c:1284
 __mmput+0x118/0x410 kernel/fork.c:1379
 exit_mm+0x1da/0x2c0 kernel/exit.c:589
 do_exit+0x859/0x2550 kernel/exit.c:940
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 get_signal+0x125e/0x1310 kernel/signal.c:3034
 arch_do_signal_or_restart+0x95/0x780 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x8b/0x120 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1127d8e969
Code: Unable to access opcode bytes at 0x7f1127d8e93f.
RSP: 002b:00007f1128b46038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: 0000000000010106 RBX: 00007f1127fb6080 RCX: 00007f1127d8e969
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007f1127e10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1127fb6080 R15: 00007ffe52dce118
 </TASK>