Warning: Permanently added '10.128.0.253' (ED25519) to the list of known hosts. executing program [ 115.270589][ T5845] [ 115.273133][ T5845] ====================================================== [ 115.281940][ T5845] WARNING: possible circular locking dependency detected [ 115.290207][ T5845] 6.16.0-rc1-syzkaller-00003-gf09079bd04a9 #0 Not tainted [ 115.298333][ T5845] ------------------------------------------------------ [ 115.306535][ T5845] syz-executor418/5845 is trying to acquire lock: [ 115.313946][ T5845] ffffffff8e2666d0 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_slow_inc+0x12/0x30 [ 115.325202][ T5845] [ 115.325202][ T5845] but task is already holding lock: [ 115.333054][ T5845] ffff888025eaa9c8 (&q->rq_qos_mutex){+.+.}-{4:4}, at: wbt_init+0x393/0x540 [ 115.342163][ T5845] [ 115.342163][ T5845] which lock already depends on the new lock. [ 115.342163][ T5845] [ 115.353395][ T5845] [ 115.353395][ T5845] the existing dependency chain (in reverse order) is: [ 115.362983][ T5845] [ 115.362983][ T5845] -> #3 (&q->rq_qos_mutex){+.+.}-{4:4}: [ 115.371309][ T5845] __mutex_lock+0x199/0xb90 [ 115.377103][ T5845] wbt_init+0x393/0x540 [ 115.382438][ T5845] queue_wb_lat_store+0x354/0x3d0 [ 115.389041][ T5845] queue_attr_store+0x279/0x320 [ 115.395006][ T5845] sysfs_kf_write+0xf2/0x150 [ 115.400602][ T5845] kernfs_fop_write_iter+0x351/0x510 [ 115.406722][ T5845] vfs_write+0x6c4/0x1150 [ 115.412222][ T5845] ksys_write+0x12a/0x250 [ 115.417892][ T5845] do_syscall_64+0xcd/0x490 [ 115.423408][ T5845] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 115.430212][ T5845] [ 115.430212][ T5845] -> #2 (&q->q_usage_counter(io)#18){++++}-{0:0}: [ 115.439144][ T5845] blk_alloc_queue+0x619/0x760 [ 115.444597][ T5845] blk_mq_alloc_queue+0x175/0x290 [ 115.450469][ T5845] __blk_mq_alloc_disk+0x29/0x120 [ 115.456382][ T5845] loop_add+0x49e/0xb70 [ 115.461543][ T5845] loop_init+0x164/0x270 [ 115.466846][ T5845] do_one_initcall+0x120/0x6e0 [ 115.472368][ T5845] kernel_init_freeable+0x5c2/0x900 [ 115.478987][ T5845] kernel_init+0x1c/0x2b0 [ 115.484960][ T5845] ret_from_fork+0x5d4/0x6f0 [ 115.491006][ T5845] ret_from_fork_asm+0x1a/0x30 [ 115.496751][ T5845] [ 115.496751][ T5845] -> #1 (fs_reclaim){+.+.}-{0:0}: [ 115.505015][ T5845] fs_reclaim_acquire+0x102/0x150 [ 115.511494][ T5845] __kmalloc_cache_node_noprof+0x53/0x420 [ 115.518920][ T5845] create_worker+0x10f/0x7e0 [ 115.524304][ T5845] workqueue_prepare_cpu+0xb5/0x160 [ 115.530725][ T5845] cpuhp_invoke_callback+0x3d5/0xa10 [ 115.536855][ T5845] __cpuhp_invoke_callback_range+0x101/0x210 [ 115.543777][ T5845] _cpu_up+0x3f5/0x930 [ 115.548517][ T5845] cpu_up+0x1dc/0x240 [ 115.554518][ T5845] cpuhp_bringup_mask+0xd8/0x210 [ 115.560582][ T5845] bringup_nonboot_cpus+0x176/0x1c0 [ 115.566720][ T5845] smp_init+0x34/0x160 [ 115.571536][ T5845] kernel_init_freeable+0x3a8/0x900 [ 115.577578][ T5845] kernel_init+0x1c/0x2b0 [ 115.583373][ T5845] ret_from_fork+0x5d4/0x6f0 [ 115.589034][ T5845] ret_from_fork_asm+0x1a/0x30 [ 115.595369][ T5845] [ 115.595369][ T5845] -> #0 (cpu_hotplug_lock){++++}-{0:0}: [ 115.603990][ T5845] __lock_acquire+0x126f/0x1c90 [ 115.609702][ T5845] lock_acquire+0x179/0x350 [ 115.615263][ T5845] cpus_read_lock+0x42/0x160 [ 115.620563][ T5845] static_key_slow_inc+0x12/0x30 [ 115.626339][ T5845] rq_qos_add+0x2f8/0x4b0 [ 115.631564][ T5845] wbt_init+0x3a9/0x540 [ 115.636436][ T5845] queue_wb_lat_store+0x354/0x3d0 [ 115.642088][ T5845] queue_attr_store+0x279/0x320 [ 115.647698][ T5845] sysfs_kf_write+0xf2/0x150 [ 115.653310][ T5845] kernfs_fop_write_iter+0x351/0x510 [ 115.659263][ T5845] vfs_write+0x6c4/0x1150 [ 115.664208][ T5845] ksys_write+0x12a/0x250 [ 115.669116][ T5845] do_syscall_64+0xcd/0x490 [ 115.674459][ T5845] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 115.681492][ T5845] [ 115.681492][ T5845] other info that might help us debug this: [ 115.681492][ T5845] [ 115.692799][ T5845] Chain exists of: [ 115.692799][ T5845] cpu_hotplug_lock --> &q->q_usage_counter(io)#18 --> &q->rq_qos_mutex [ 115.692799][ T5845] [ 115.708514][ T5845] Possible unsafe locking scenario: [ 115.708514][ T5845] [ 115.718210][ T5845] CPU0 CPU1 [ 115.723868][ T5845] ---- ---- [ 115.729926][ T5845] lock(&q->rq_qos_mutex); [ 115.734826][ T5845] lock(&q->q_usage_counter(io)#18); [ 115.743127][ T5845] lock(&q->rq_qos_mutex); [ 115.750786][ T5845] rlock(cpu_hotplug_lock); [ 115.755652][ T5845] [ 115.755652][ T5845] *** DEADLOCK *** [ 115.755652][ T5845] [ 115.764590][ T5845] 6 locks held by syz-executor418/5845: [ 115.770205][ T5845] #0: ffff88803576a428 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 [ 115.780623][ T5845] #1: ffff888034ce5488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x510 [ 115.791948][ T5845] #2: ffff888025f405a8 (kn->active#50){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b2/0x510 [ 115.803664][ T5845] #3: ffff888025eaa7c8 (&q->q_usage_counter(io)#18){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x15/0x20 [ 115.817496][ T5845] #4: ffff888025eaa800 (&q->q_usage_counter(queue)#20){+.+.}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x15/0x20 [ 115.829800][ T5845] #5: ffff888025eaa9c8 (&q->rq_qos_mutex){+.+.}-{4:4}, at: wbt_init+0x393/0x540 [ 115.839502][ T5845] [ 115.839502][ T5845] stack backtrace: [ 115.846041][ T5845] CPU: 0 UID: 0 PID: 5845 Comm: syz-executor418 Not tainted 6.16.0-rc1-syzkaller-00003-gf09079bd04a9 #0 PREEMPT(full) [ 115.846078][ T5845] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 [ 115.846098][ T5845] Call Trace: [ 115.846113][ T5845] [ 115.846127][ T5845] dump_stack_lvl+0x116/0x1f0 [ 115.846179][ T5845] print_circular_bug+0x275/0x350 [ 115.846215][ T5845] check_noncircular+0x14c/0x170 [ 115.846252][ T5845] __lock_acquire+0x126f/0x1c90 [ 115.846292][ T5845] lock_acquire+0x179/0x350 [ 115.846324][ T5845] ? static_key_slow_inc+0x12/0x30 [ 115.846361][ T5845] ? __pfx___might_resched+0x10/0x10 [ 115.846397][ T5845] cpus_read_lock+0x42/0x160 [ 115.846428][ T5845] ? static_key_slow_inc+0x12/0x30 [ 115.846461][ T5845] static_key_slow_inc+0x12/0x30 [ 115.846496][ T5845] rq_qos_add+0x2f8/0x4b0 [ 115.846535][ T5845] wbt_init+0x3a9/0x540 [ 115.846564][ T5845] queue_wb_lat_store+0x354/0x3d0 [ 115.846608][ T5845] ? __pfx_queue_wb_lat_store+0x10/0x10 [ 115.846652][ T5845] ? __mutex_trylock_common+0xe9/0x250 [ 115.846688][ T5845] ? __pfx_queue_wb_lat_store+0x10/0x10 [ 115.846730][ T5845] queue_attr_store+0x279/0x320 [ 115.846772][ T5845] ? __pfx_queue_attr_store+0x10/0x10 [ 115.846813][ T5845] ? __lock_acquire+0x622/0x1c90 [ 115.846854][ T5845] ? find_held_lock+0x2b/0x80 [ 115.846878][ T5845] ? sysfs_file_kobj+0xe4/0x290 [ 115.846912][ T5845] ? __pfx_queue_attr_store+0x10/0x10 [ 115.846954][ T5845] sysfs_kf_write+0xf2/0x150 [ 115.846985][ T5845] kernfs_fop_write_iter+0x351/0x510 [ 115.847012][ T5845] ? __pfx_sysfs_kf_write+0x10/0x10 [ 115.847044][ T5845] vfs_write+0x6c4/0x1150 [ 115.847081][ T5845] ? __pfx_kernfs_fop_write_iter+0x10/0x10 [ 115.847111][ T5845] ? __pfx_vfs_write+0x10/0x10 [ 115.847149][ T5845] ? find_held_lock+0x2b/0x80 [ 115.847176][ T5845] ? find_held_lock+0x2b/0x80 [ 115.847202][ T5845] ksys_write+0x12a/0x250 [ 115.847238][ T5845] ? __pfx_ksys_write+0x10/0x10 [ 115.847280][ T5845] do_syscall_64+0xcd/0x490 [ 115.847305][ T5845] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 115.847332][ T5845] RIP: 0033:0x7f14c58f0a39 [ 115.847363][ T5845] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 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 b8 ff ff ff f7 d8 64 89 01 48 [ 115.847397][ T5845] RSP: 002b:00007ffc6b488bd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 115.847421][ T5845] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f14c58f0a39 [ 115.847438][ T5845] RDX: 0000000000000009 RSI: 00002000000001c0 RDI: 0000000000000003 executing program [ 115.847454][ T5845] RBP: 00007f14c59635f0 R08: 0000000000000006 R09: 0000000000000006 [ 115.847470][ T5845] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 115.847485][ T5845] R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001 [ 115.847509][ T5845] executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program