syzbot

INFO: task syz-executor365:5860 blocked for more than 143 seconds.
      Not tainted 6.12.0-syzkaller-10740-g509f806f7f70 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor365 state:D stack:27568 pid:5860  tgid:5857  ppid:5856   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905
 rwsem_down_write_slowpath+0xeee/0x13b0 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write_nested+0x1e0/0x220 kernel/locking/rwsem.c:1694
 inode_lock_nested include/linux/fs.h:853 [inline]
 do_unlinkat+0x26a/0x830 fs/namei.c:4574
 __do_sys_unlink fs/namei.c:4635 [inline]
 __se_sys_unlink fs/namei.c:4633 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:4633
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f859a8ed849
RSP: 002b:00007f859a883218 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007f859a9756d8 RCX: 00007f859a8ed849
RDX: ffffffffffffffb0 RSI: 0000000000000000 RDI: 0000000020000180
RBP: 00007f859a9756d0 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffcea99c467 R11: 0000000000000246 R12: 00007f859a94107e
R13: 00007f859a941086 R14: 0030656c69662f2e R15: 0031656c69662f2e
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e93c560 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e93c560 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e93c560 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
2 locks held by getty/5599:
 #0: ffff888031df60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002fee2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
3 locks held by syz-executor365/5859:
2 locks held by syz-executor365/5860:
 #0: ffff88807d9ce420 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff8880740c02a0 (&sb->s_type->i_mutex_key#14/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:853 [inline]
 #1: ffff8880740c02a0 (&sb->s_type->i_mutex_key#14/1){+.+.}-{4:4}, at: do_unlinkat+0x26a/0x830 fs/namei.c:4574

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-syzkaller-10740-g509f806f7f70 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline]
 watchdog+0xff6/0x1040 kernel/hung_task.c:397
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 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: 5859 Comm: syz-executor365 Not tainted 6.12.0-syzkaller-10740-g509f806f7f70 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:__might_resched+0x10/0x780 kernel/sched/core.c:8713
Code: 00 e9 63 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 <53> 48 83 e4 e0 48 81 ec e0 00 00 00 41 89 d4 41 89 f6 48 89 7c 24
RSP: 0018:ffffc90003f7f5f0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880740e31d0 RCX: ffff88807a810000
RDX: 0000000000000000 RSI: 0000000000000141 RDI: ffffffff8c19b2e0
RBP: ffffc90003f7f610 R08: ffffffff82229c13 R09: 1ffffffff203a106
R10: dffffc0000000000 R11: fffffbfff203a107 R12: 0000000000000008
R13: ffff888148d3b980 R14: 00000000000000a0 R15: ffff888148d3b980
FS:  00007f859a8a46c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055729940f600 CR3: 0000000078d04000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 might_alloc include/linux/sched/mm.h:321 [inline]
 bdev_getblk+0x89/0x550 fs/buffer.c:1427
 __bread_gfp+0x86/0x400 fs/buffer.c:1485
 sb_bread include/linux/buffer_head.h:346 [inline]
 exfat_get_dentry+0x53b/0x730 fs/exfat/dir.c:672
 exfat_readdir fs/exfat/dir.c:118 [inline]
 exfat_iterate+0x9f9/0x2ce0 fs/exfat/dir.c:242
 wrap_directory_iterator+0x91/0xd0 fs/readdir.c:65
 iterate_dir+0x571/0x800 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:403 [inline]
 __se_sys_getdents64+0x1e2/0x4b0 fs/readdir.c:389
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f859a8ed849
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f859a8a4218 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f859a9756c8 RCX: 00007f859a8ed849
RDX: 0000000000001000 RSI: 0000000020000f80 RDI: 0000000000000004
RBP: 00007f859a9756c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f859a94107e
R13: 00007f859a941086 R14: 0030656c69662f2e R15: 0031656c69662f2e
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.175 msecs