syzbot

INFO: task syz.0.476:8066 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.476       state:D stack:24408 pid:8066  tgid:8065  ppid:5835   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 mb_cache_entry_wait_unused+0x165/0x250 fs/mbcache.c:148
 ext4_evict_ea_inode+0x14d/0x2f0 fs/ext4/xattr.c:477
 ext4_evict_inode+0x16f/0xed0 fs/ext4/inode.c:188
 evict+0x504/0x9c0 fs/inode.c:810
 ext4_xattr_ibody_set+0x510/0x6a0 fs/ext4/xattr.c:2276
 ext4_xattr_set_handle+0xc9a/0x1590 fs/ext4/xattr.c:2435
 ext4_xattr_set+0x230/0x320 fs/ext4/xattr.c:2549
 __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_setxattr fs/xattr.c:747 [inline]
 __se_sys_setxattr fs/xattr.c:743 [inline]
 __x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:743
 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: 0033:0x7fc7af78e969
RSP: 002b:00007fc7ad5f6038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007fc7af9b5fa0 RCX: 00007fc7af78e969
RDX: 0000200000001400 RSI: 00002000000001c0 RDI: 0000200000000380
RBP: 00007fc7af810ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000835 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc7af9b5fa0 R15: 00007ffd79807718
 </TASK>
INFO: task syz.0.476:8073 blocked for more than 144 seconds.
      Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.476       state:D stack:27016 pid:8073  tgid:8065  ppid:5835   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 __wait_on_freeing_inode+0x1c5/0x2f0 fs/inode.c:2454
 find_inode_fast+0x2b0/0x470 fs/inode.c:1070
 iget_locked+0x99/0x570 fs/inode.c:1427
 __ext4_iget+0x245/0x3e30 fs/ext4/inode.c:4800
 ext4_xattr_inode_cache_find fs/ext4/xattr.c:1540 [inline]
 ext4_xattr_inode_lookup_create+0x433/0x1c20 fs/ext4/xattr.c:1579
 ext4_xattr_block_set+0x223/0x2ac0 fs/ext4/xattr.c:1908
 ext4_xattr_set_handle+0xdfb/0x1590 fs/ext4/xattr.c:2447
 ext4_xattr_set+0x230/0x320 fs/ext4/xattr.c:2549
 __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_setxattr fs/xattr.c:747 [inline]
 __se_sys_setxattr fs/xattr.c:743 [inline]
 __x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:743
 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: 0033:0x7fc7af78e969
RSP: 002b:00007fc7ad5d5038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007fc7af9b6080 RCX: 00007fc7af78e969
RDX: 0000200000001400 RSI: 0000200000000080 RDI: 00002000000000c0
RBP: 00007fc7af810ab1 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000835 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fc7af9b6080 R15: 00007ffd79807718
 </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/5577:
 #0: ffff88802feb30a0 (&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
4 locks held by kworker/u8:8/6070:
 #0: ffff8880b8839b58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605
 #1: ffff8880b8823b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987
 #2: ffff8880b8825558 (&base->lock){-.-.}-{2:2}, at: lock_timer_base kernel/time/timer.c:1046 [inline]
 #2: ffff8880b8825558 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30 kernel/time/timer.c:1127
 #3: ffffffff99a4e100 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0xbb/0x420 lib/debugobjects.c:818
3 locks held by syz.0.476/8066:
 #0: ffff8880578da420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556
 #1: ffff888055868438 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff888055868438 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff8880558680c8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline]
 #2: ffff8880558680c8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x165/0x1590 fs/ext4/xattr.c:2362
3 locks held by syz.0.476/8073:
 #0: ffff8880578da420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556
 #1: ffff888055869808 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff888055869808 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff888055869498 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline]
 #2: ffff888055869498 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x165/0x1590 fs/ext4/xattr.c:2362
5 locks held by kworker/u8:14/8743:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #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+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4e/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: 8743 Comm: kworker/u8:14 Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:107 [inline]
RIP: 0010:raw_atomic_try_cmpxchg_acquire include/linux/atomic/atomic-arch-fallback.h:2170 [inline]
RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1302 [inline]
RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
RIP: 0010:do_raw_spin_lock+0x125/0x290 kernel/locking/spinlock_debug.c:116
Code: 00 00 c7 44 24 40 00 00 00 00 48 89 df be 04 00 00 00 e8 6e 05 83 00 48 8d 7c 24 40 be 04 00 00 00 e8 5f 05 83 00 8b 44 24 40 <b9> 01 00 00 00 f0 0f b1 0b 0f 85 dd 00 00 00 65 8b 1d 39 8f d6 10
RSP: 0018:ffffc9000484f960 EFLAGS: 00000297
RAX: 0000000000000000 RBX: ffff88805aa51500 RCX: ffffffff819eb0e1
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc9000484f9a0
RBP: ffffc9000484fa18 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000909f34 R12: ffff88805aa51510
R13: ffff88805aa51508 R14: 1ffff1100b54a2a2 R15: 1ffff1100b54a2a1
FS:  0000000000000000(0000) GS:ffff8881261cc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd09b62fb8 CR3: 000000007d270000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:442
 batadv_nc_worker+0x328/0x610 net/batman-adv/network-coding.c:720
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>