------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
5.15.179-syzkaller #0 Not tainted
------------------------------------------------------
ksoftirqd/0/14 is trying to acquire lock:
ffffffff8c9fbd38 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:138

but task is already holding lock:
ffff8880b8e2a218 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:1692 [inline]
ffff8880b8e2a218 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x662/0xcf0 kernel/time/hrtimer.c:1752

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (hrtimer_bases.lock){-.-.}-{2:2}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       lock_hrtimer_base kernel/time/hrtimer.c:173 [inline]
       hrtimer_start_range_ns+0x105/0xc80 kernel/time/hrtimer.c:1299
       hrtimer_start_expires include/linux/hrtimer.h:434 [inline]
       do_start_rt_bandwidth kernel/sched/rt.c:69 [inline]
       start_rt_bandwidth kernel/sched/rt.c:80 [inline]
       inc_rt_group kernel/sched/rt.c:1207 [inline]
       inc_rt_tasks kernel/sched/rt.c:1251 [inline]
       __enqueue_rt_entity kernel/sched/rt.c:1321 [inline]
       enqueue_rt_entity kernel/sched/rt.c:1368 [inline]
       enqueue_task_rt+0x5a0/0xbf0 kernel/sched/rt.c:1398
       enqueue_task+0x19d/0x2e0 kernel/sched/core.c:1976
       __sched_setscheduler+0x1396/0x1db0 kernel/sched/core.c:7550
       _sched_setscheduler kernel/sched/core.c:7597 [inline]
       sched_setscheduler_nocheck kernel/sched/core.c:7644 [inline]
       sched_set_fifo+0x10e/0x1e0 kernel/sched/core.c:7668
       drm_vblank_worker_init+0x149/0x190 drivers/gpu/drm/drm_vblank_work.c:263
       drm_vblank_init+0x274/0x330 drivers/gpu/drm/drm_vblank.c:551
       vkms_create drivers/gpu/drm/vkms/vkms_drv.c:195 [inline]
       vkms_init+0x330/0x6d0 drivers/gpu/drm/vkms/vkms_drv.c:235
       do_one_initcall+0x22b/0x7a0 init/main.c:1302
       do_initcall_level+0x157/0x210 init/main.c:1375
       do_initcalls+0x49/0x90 init/main.c:1391
       kernel_init_freeable+0x425/0x5c0 init/main.c:1615
       kernel_init+0x19/0x290 init/main.c:1506
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #3 (&rt_b->rt_runtime_lock){-...}-{2:2}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
       __enable_runtime kernel/sched/rt.c:840 [inline]
       rq_online_rt+0x123/0x300 kernel/sched/rt.c:2331
       set_rq_online kernel/sched/core.c:9036 [inline]
       sched_cpu_activate+0x508/0x6b0 kernel/sched/core.c:9156
       cpuhp_invoke_callback+0x49f/0x820 kernel/cpu.c:191
       cpuhp_thread_fun+0x3ee/0x790 kernel/cpu.c:822
       smpboot_thread_fn+0x51b/0x9d0 kernel/smpboot.c:164
       kthread+0x3f6/0x4f0 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #2 (&rq->__lock){-.-.}-{2:2}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:368
       raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
       raw_spin_rq_lock kernel/sched/sched.h:1326 [inline]
       rq_lock kernel/sched/sched.h:1621 [inline]
       task_fork_fair+0x5d/0x350 kernel/sched/fair.c:11499
       sched_cgroup_fork+0x2d3/0x330 kernel/sched/core.c:4465
       copy_process+0x224a/0x3ef0 kernel/fork.c:2319
       kernel_clone+0x210/0x960 kernel/fork.c:2603
       kernel_thread+0x12e/0x1a0 kernel/fork.c:2655
       rest_init+0x21/0x330 init/main.c:706
       start_kernel+0x48c/0x540 init/main.c:1140
       secondary_startup_64_no_verify+0xb1/0xbb

-> #1 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       try_to_wake_up+0xae/0x12c0 kernel/sched/core.c:4029
       up+0x6e/0x90 kernel/locking/semaphore.c:190
       __up_console_sem+0x11a/0x1e0 kernel/printk/printk.c:256
       console_unlock+0x1145/0x12b0 kernel/printk/printk.c:2760
       vprintk_emit+0xbf/0x150 kernel/printk/printk.c:2274
       dev_vprintk_emit+0x2aa/0x330 drivers/base/core.c:4638
       dev_printk_emit+0xd9/0x120 drivers/base/core.c:4649
       _dev_warn+0x11e/0x170 drivers/base/core.c:4705
       firmware_fallback_sysfs+0x681/0xc90 drivers/base/firmware_loader/fallback.c:654
       _request_firmware+0xc72/0x12c0 drivers/base/firmware_loader/main.c:876
       request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1127
       process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
       worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
       kthread+0x3f6/0x4f0 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #0 ((console_sem).lock){-.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:138
       __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:239
       console_trylock kernel/printk/printk.c:2575 [inline]
       console_trylock_spinning+0x8a/0x3f0 kernel/printk/printk.c:1867
       vprintk_emit+0xa6/0x150 kernel/printk/printk.c:2273
       _printk+0xd1/0x120 kernel/printk/printk.c:2299
       report_bug+0x1e5/0x2e0 lib/bug.c:195
       handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239
       exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:259
       asm_exc_invalid_op+0x16/0x20 arch/x86/include/asm/idtentry.h:604
       copy_from_user_nofault+0x15c/0x1c0 mm/maccess.c:-1
       bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline]
       ____bpf_probe_read_compat kernel/trace/bpf_trace.c:281 [inline]
       bpf_probe_read_compat+0xe4/0x180 kernel/trace/bpf_trace.c:277
       bpf_prog_3d2613b5dfc7747f+0x32/0x560
       bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
       __bpf_prog_run include/linux/filter.h:628 [inline]
       bpf_prog_run include/linux/filter.h:635 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
       bpf_trace_run2+0x19e/0x340 kernel/trace/bpf_trace.c:1915
       trace_hrtimer_start include/trace/events/timer.h:199 [inline]
       debug_activate kernel/time/hrtimer.c:476 [inline]
       enqueue_hrtimer+0x324/0x390 kernel/time/hrtimer.c:1084
       __run_hrtimer kernel/time/hrtimer.c:1705 [inline]
       __hrtimer_run_queues+0x6b6/0xcf0 kernel/time/hrtimer.c:1752
       hrtimer_run_softirq+0x196/0x2c0 kernel/time/hrtimer.c:1769
       handle_softirqs+0x3a7/0x930 kernel/softirq.c:558
       run_ksoftirqd+0xc6/0x120 kernel/softirq.c:925
       smpboot_thread_fn+0x51b/0x9d0 kernel/smpboot.c:164
       kthread+0x3f6/0x4f0 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

other info that might help us debug this:

Chain exists of:
  (console_sem).lock --> &rt_b->rt_runtime_lock --> hrtimer_bases.lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(hrtimer_bases.lock);
                               lock(&rt_b->rt_runtime_lock);
                               lock(hrtimer_bases.lock);
  lock((console_sem).lock);

 *** DEADLOCK ***

2 locks held by ksoftirqd/0/14:
 #0: ffff8880b8e2a218 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:1692 [inline]
 #0: ffff8880b8e2a218 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x662/0xcf0 kernel/time/hrtimer.c:1752
 #1: ffffffff8cb1f4e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311

stack backtrace:
CPU: 0 PID: 14 Comm: ksoftirqd/0 Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
 down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:138
 __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:239
 console_trylock kernel/printk/printk.c:2575 [inline]
 console_trylock_spinning+0x8a/0x3f0 kernel/printk/printk.c:1867
 vprintk_emit+0xa6/0x150 kernel/printk/printk.c:2273
 _printk+0xd1/0x120 kernel/printk/printk.c:2299
 report_bug+0x1e5/0x2e0 lib/bug.c:195
 handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239
 exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:259
 asm_exc_invalid_op+0x16/0x20 arch/x86/include/asm/idtentry.h:604
RIP: 0010:copy_from_user_nofault+0x15c/0x1c0 mm/maccess.c:226
Code: db 48 c7 c0 f2 ff ff ff 48 0f 44 c5 eb 0c e8 9b b0 d5 ff 48 c7 c0 f2 ff ff ff 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 84 b0 d5 ff <0f> 0b e9 1e ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c ef fe ff
RSP: 0018:ffffc90000d37990 EFLAGS: 00010046
RAX: ffffffff81aaec3c RBX: 0000000000000000 RCX: ffff88813ff21dc0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff81aaeb4d R09: ffffed1027fe43b9
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90000d37a08
 bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline]
 ____bpf_probe_read_compat kernel/trace/bpf_trace.c:281 [inline]
 bpf_probe_read_compat+0xe4/0x180 kernel/trace/bpf_trace.c:277
 bpf_prog_3d2613b5dfc7747f+0x32/0x560
 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
 bpf_trace_run2+0x19e/0x340 kernel/trace/bpf_trace.c:1915
 trace_hrtimer_start include/trace/events/timer.h:199 [inline]
 debug_activate kernel/time/hrtimer.c:476 [inline]
 enqueue_hrtimer+0x324/0x390 kernel/time/hrtimer.c:1084
 __run_hrtimer kernel/time/hrtimer.c:1705 [inline]
 __hrtimer_run_queues+0x6b6/0xcf0 kernel/time/hrtimer.c:1752
 hrtimer_run_softirq+0x196/0x2c0 kernel/time/hrtimer.c:1769
 handle_softirqs+0x3a7/0x930 kernel/softirq.c:558
 run_ksoftirqd+0xc6/0x120 kernel/softirq.c:925
 smpboot_thread_fn+0x51b/0x9d0 kernel/smpboot.c:164
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
WARNING: CPU: 0 PID: 14 at mm/maccess.c:226 copy_from_user_nofault+0x15c/0x1c0 mm/maccess.c:-1
Modules linked in:
CPU: 0 PID: 14 Comm: ksoftirqd/0 Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:copy_from_user_nofault+0x15c/0x1c0 mm/maccess.c:226
Code: db 48 c7 c0 f2 ff ff ff 48 0f 44 c5 eb 0c e8 9b b0 d5 ff 48 c7 c0 f2 ff ff ff 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 84 b0 d5 ff <0f> 0b e9 1e ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c ef fe ff
RSP: 0018:ffffc90000d37990 EFLAGS: 00010046
RAX: ffffffff81aaec3c RBX: 0000000000000000 RCX: ffff88813ff21dc0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff81aaeb4d R09: ffffed1027fe43b9
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90000d37a08
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557e0a5808 CR3: 0000000065c1f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline]
 ____bpf_probe_read_compat kernel/trace/bpf_trace.c:281 [inline]
 bpf_probe_read_compat+0xe4/0x180 kernel/trace/bpf_trace.c:277
 bpf_prog_3d2613b5dfc7747f+0x32/0x560
 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
 bpf_trace_run2+0x19e/0x340 kernel/trace/bpf_trace.c:1915
 trace_hrtimer_start include/trace/events/timer.h:199 [inline]
 debug_activate kernel/time/hrtimer.c:476 [inline]
 enqueue_hrtimer+0x324/0x390 kernel/time/hrtimer.c:1084
 __run_hrtimer kernel/time/hrtimer.c:1705 [inline]
 __hrtimer_run_queues+0x6b6/0xcf0 kernel/time/hrtimer.c:1752
 hrtimer_run_softirq+0x196/0x2c0 kernel/time/hrtimer.c:1769
 handle_softirqs+0x3a7/0x930 kernel/softirq.c:558
 run_ksoftirqd+0xc6/0x120 kernel/softirq.c:925
 smpboot_thread_fn+0x51b/0x9d0 kernel/smpboot.c:164
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>