syzbot

INFO: task syz-executor331:4271 blocked for more than 143 seconds.
      Not tainted 6.1.138-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor331 state:D stack:24400 pid:4271  ppid:4270   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 wait_on_state fs/btrfs/extent-io-tree.c:709 [inline]
 wait_extent_bit+0x3f1/0x550 fs/btrfs/extent-io-tree.c:742
 lock_extent+0xcc/0x140 fs/btrfs/extent-io-tree.c:1657
 btrfs_page_mkwrite+0x516/0xbf0 fs/btrfs/inode.c:8622
 do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3011
 wp_page_shared+0x167/0x370 mm/memory.c:3360
 handle_pte_fault mm/memory.c:5049 [inline]
 __handle_mm_fault mm/memory.c:5173 [inline]
 handle_mm_fault+0x1ca6/0x3e70 mm/memory.c:5294
 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: 0010:copy_user_short_string+0xd/0x40 arch/x86/lib/copy_user_64.S:233
Code: 74 0a 89 d1 f3 a4 89 c8 0f 01 ca c3 89 d0 0f 01 ca c3 01 ca eb e7 90 90 90 90 90 90 90 89 d1 83 e2 07 c1 e9 03 74 12 4c 8b 06 <4c> 89 07 48 8d 76 08 48 8d 7f 08 ff c9 75 ee 21 d2 74 10 89 d1 8a
RSP: 0018:ffffc90003d775c8 EFLAGS: 00050202
RAX: ffffffff8407a301 RBX: 0000000000000038 RCX: 0000000000000007
RDX: 0000000000000000 RSI: ffffc90003d77660 RDI: 00002000000003a0
RBP: 0000000000000000 R08: 0000000000000000 R09: fffff520007aeed3
R10: fffff520007aeed3 R11: 1ffff920007aeecc R12: 00007fffffffefc8
R13: 1ffff920007aeec8 R14: 00002000000003a0 R15: ffffc90003d77660
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 _copy_to_user+0xea/0x130 lib/usercopy.c:41
 copy_to_user include/linux/uaccess.h:169 [inline]
 fiemap_fill_next_extent+0x19d/0x360 fs/ioctl.c:144
 emit_last_fiemap_cache fs/btrfs/extent_io.c:3595 [inline]
 extent_fiemap+0x1679/0x19b0 fs/btrfs/extent_io.c:4126
 btrfs_fiemap+0x152/0x1b0 fs/btrfs/inode.c:8294
 ioctl_fiemap fs/ioctl.c:219 [inline]
 do_vfs_ioctl+0x1425/0x1d10 fs/ioctl.c:810
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl+0x83/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f23e7b0dbd9
RSP: 002b:00007ffef3501198 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f23e7b0dbd9
RDX: 0000200000000380 RSI: 00000000c020660b RDI: 0000000000000004
RBP: 00007f23e7ba35f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffef35011d0
R13: 00007ffef35013f8 R14: 431bde82d7b634db R15: 00007f23e7b5603b
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8c92b2f0 (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: ffffffff8c92bb10 (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/27:
 #0: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4013:
 #0: ffff88807e1b0098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
4 locks held by syz-executor331/4271:
 #0: ffff888072b79920 (&sb->s_type->i_mutex_key#15){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline]
 #0: ffff888072b79920 (&sb->s_type->i_mutex_key#15){++++}-{3:3}, at: btrfs_inode_lock+0x61/0xe0 fs/btrfs/inode.c:147
 #1: ffff8880192d0158 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #1: ffff8880192d0158 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5322 [inline]
 #1: ffff8880192d0158 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5384
 #2: ffff888023d34558 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3011
 #3: ffff888072b797a8 (&ei->i_mmap_lock){.+.+}-{3:3}, at: btrfs_page_mkwrite+0x3f1/0xbf0 fs/btrfs/inode.c:8611

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 6.1.138-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3f4/0x470 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 46 Comm: kworker/u4:3 Not tainted 6.1.138-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:215
Code: 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d b0 b0 7d 0c 48 89 de 5b e9 67 aa 50 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d 84 9b 81 7e 65 8b 15 85 9b 81 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc90000b77778 EFLAGS: 00000246
RAX: ffffffff8a036257 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff88801c2a1dc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000b77980 R08: dffffc0000000000 R09: ffffc90000b77960
R10: fffff5200016ef37 R11: 1ffff9200016ef2c R12: ffffc90000b77985
R13: ffffc90000b77984 R14: ffffc90000b77960 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556006d42660 CR3: 000000000c68e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 insn_get_modrm+0x247/0x7a0 arch/x86/lib/insn.c:351
 insn_get_sib arch/x86/lib/insn.c:421 [inline]
 insn_get_displacement+0x156/0xa20 arch/x86/lib/insn.c:464
 insn_get_immediate+0x325/0x1290 arch/x86/lib/insn.c:632
 insn_get_length arch/x86/lib/insn.c:707 [inline]
 insn_decode+0x386/0x520 arch/x86/lib/insn.c:747
 text_poke_loc_init+0xd6/0x570 arch/x86/kernel/alternative.c:1638
 arch_jump_label_transform_queue+0x6a/0xd0 arch/x86/kernel/jump_label.c:138
 __jump_label_update+0x17d/0x390 kernel/jump_label.c:510
 static_key_disable_cpuslocked+0xc1/0x1a0 kernel/jump_label.c:237
 static_key_disable+0x16/0x20 kernel/jump_label.c:245
 toggle_allocation_gate+0x38f/0x430 mm/kfence/core.c:819
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>