syzbot

INFO: task syz.0.17:6050 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:24648 pid:6050  tgid:6050  ppid:5978   task_flags:0x440140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7058
 xlog_grant_head_wait+0x453/0xa20 fs/xfs/xfs_log.c:267
 xlog_grant_head_check+0x286/0x420 fs/xfs/xfs_log.c:-1
 xfs_log_reserve+0x2cc/0x780 fs/xfs/xfs_log.c:437
 xfs_trans_reserve fs/xfs/xfs_trans.c:176 [inline]
 xfs_trans_alloc+0x29c/0x980 fs/xfs/xfs_trans.c:258
 xfs_trans_alloc_inode+0x13c/0x4a0 fs/xfs/xfs_trans.c:1075
 xfs_attr_set+0x7fa/0x1210 fs/xfs/libxfs/xfs_attr.c:1098
 xfs_xattr_set+0x14d/0x250 fs/xfs/xfs_xattr.c:186
 __vfs_setxattr+0x43c/0x480 fs/xattr.c:200
 __vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234
 vfs_setxattr+0x16b/0x2f0 fs/xattr.c:321
 do_setxattr fs/xattr.c:636 [inline]
 filename_setxattr+0x274/0x600 fs/xattr.c:665
 path_setxattrat+0x364/0x3a0 fs/xattr.c:713
 __do_sys_lsetxattr fs/xattr.c:754 [inline]
 __se_sys_lsetxattr fs/xattr.c:750 [inline]
 __x64_sys_lsetxattr+0xbf/0xe0 fs/xattr.c:750
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f958ab8ebe9
RSP: 002b:00007fff84a331f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f958adb5fa0 RCX: 00007f958ab8ebe9
RDX: 0000200000000100 RSI: 0000200000000040 RDI: 0000200000000000
RBP: 00007f958ac11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000fffe R11: 0000000000000246 R12: 0000000000000000
R13: 00007f958adb5fa0 R14: 00007f958adb5fa0 R15: 0000000000000005
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5622:
 #0: ffff88802ffa10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by syz.0.17/6050:
 #0: ffff888032558428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff8880572a1a70 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff8880572a1a70 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff888032558618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
3 locks held by syz.1.18/6086:
 #0: ffff88807c388428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff8880573a1a70 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff8880573a1a70 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff88807c388618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
3 locks held by syz.2.19/6116:
 #0: ffff88802810c428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff8880573a3970 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff8880573a3970 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff88802810c618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
3 locks held by syz.3.20/6146:
 #0: ffff888074a74428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff8880572a3970 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff8880572a3970 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff888074a74618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
3 locks held by syz.4.21/6188:
 #0: ffff888024644428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff8880572a5870 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff8880572a5870 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff888024644618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
3 locks held by syz.5.22/6223:
 #0: ffff88807b598428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff8880573a5870 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff8880573a5870 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff88807b598618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
3 locks held by syz.6.23/6258:
 #0: ffff88807d98e428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff8880573a7770 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff8880573a7770 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff88807d98e618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
3 locks held by syz.7.24/6293:
 #0: ffff888027e66428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff8880572a7770 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff8880572a7770 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff888027e66618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
3 locks held by syz.8.25/6335:
 #0: ffff88807c46a428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff888072a19a70 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff888072a19a70 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff88807c46a618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
 watchdog+0xf93/0xfe0 kernel/hung_task.c:491
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 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: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 3e 9d 96 f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d f3 86 0e 00 f3 0f 1e fa fb f4 <e9> 13 9d 96 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c2
RAX: 40c90249b3896e00 RBX: ffffffff819683c8 RCX: 40c90249b3896e00
RDX: 0000000000000001 RSI: ffffffff8d9b77e3 RDI: ffffffff8be33680
RBP: ffffc90000197f20 R08: ffff8880b8732f9b R09: 1ffff110170e65f3
R10: dffffc0000000000 R11: ffffed10170e65f4 R12: ffffffff8fa38a30
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110039d9b40
FS:  0000000000000000(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d206f92a38 CR3: 000000000df36000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:757
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x147
 </TASK>