WARNING: suspicious RCU usage in cancel_delayed_work_sync

Status: upstream: reported on 2026/08/14 15:11
Subsystems: mmc
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+9c1988bc953fca2086a3@syzkaller.appspotmail.com
First crash: 1d14h, last: 6h46m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
7f49902c assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING: suspicious RCU usage in cancel_delayed_work_sync 2026/08/15 00:46 2026/08/15 00:46 2026/08/15 01:12 746171ee
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mmc?] WARNING: suspicious RCU usage in cancel_delayed_work_sync 0 (1) 2026/08/14 15:11

Sample crash report:
=============================
WARNING: suspicious RCU usage
syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:9159 Illegal context switch in RCU-sched read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
5 locks held by syz.1.204/6027:
 #0: ffff88813c1b67b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 #0: ffff88813c1b67b8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x124/0xa00 mm/mmap.c:1284
 #1: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #1: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #1: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290
 #2: ffff888124c97618 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
 #2: ffff888124c97618 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x10f/0x320 mm/pgtable-generic.c:404
 #3: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #3: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: rcu_read_lock_sched include/linux/rcupdate.h:938 [inline]
 #3: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: pfn_valid+0xbc/0x4a0 include/linux/mmzone.h:2270
 #4: ffffc900001a8ca0 ((&vub300->inactivity_timer)){+.-.}-{0:0}, at: call_timer_fn+0x11f/0x610 kernel/time/timer.c:1745

stack backtrace:
CPU: 1 UID: 0 PID: 6027 Comm: syz.1.204 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 lockdep_rcu_suspicious.cold+0x4f/0xb1 kernel/locking/lockdep.c:6876
 __might_resched+0x2e0/0x330 kernel/sched/core.c:9159
 __cancel_work_sync kernel/workqueue.c:4487 [inline]
 cancel_delayed_work_sync+0xb8/0xf0 kernel/workqueue.c:4568
 mmc_free_host+0x19/0x30 drivers/mmc/core/host.c:700
 vub300_delete drivers/mmc/host/vub300.c:379 [inline]
 kref_put include/linux/kref.h:65 [inline]
 vub300_inactivity_timer_expired drivers/mmc/host/vub300.c:747 [inline]
 vub300_inactivity_timer_expired+0x42f/0x550 drivers/mmc/host/vub300.c:742
 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers+0x757/0xb00 kernel/time/timer.c:2374
 __run_timer_base kernel/time/timer.c:2386 [inline]
 __run_timer_base kernel/time/timer.c:2378 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2395
 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
 handle_softirqs+0x1dd/0x990 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x160/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:write_comp_data+0x40/0x90 kernel/kcov.c:246
Code: 4a 0b a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 80 6b cb 05 8b 87 44 16 00 00 85 c0 74 f1 8b 87 18 16 00 00 <83> f8 03 75 e6 48 8b 87 20 16 00 00 8b bf 1c 16 00 00 48 8b 30 48
RSP: 0018:ffffc900129f7480 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff82216c22
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff888113aa9e00
RBP: ffff88823ff5d4c0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000008
R13: 0000000000000001 R14: ffff888134aabab0 R15: 8000000131a0d067
 rcu_read_unlock_sched include/linux/rcupdate.h:960 [inline]
 pfn_valid+0x3e2/0x4a0 include/linux/mmzone.h:2280
 page_table_check_clear+0x21/0x540 mm/page_table_check.c:70
 __page_table_check_pte_clear+0x10f/0x120 mm/page_table_check.c:155
 page_table_check_pte_clear include/linux/page_table_check.h:55 [inline]
 ptep_get_and_clear_full arch/x86/include/asm/pgtable.h:1263 [inline]
 get_and_clear_full_ptes include/linux/pgtable.h:879 [inline]
 zap_present_folio_ptes mm/memory.c:1648 [inline]
 zap_present_ptes mm/memory.c:1730 [inline]
 do_zap_pte_range mm/memory.c:1832 [inline]
 zap_pte_range mm/memory.c:1934 [inline]
 zap_pmd_range mm/memory.c:2020 [inline]
 zap_pud_range mm/memory.c:2048 [inline]
 zap_p4d_range mm/memory.c:2069 [inline]
 __zap_vma_range+0x23f2/0x4000 mm/memory.c:2109
 unmap_vmas+0x299/0x5f0 mm/memory.c:2178
 exit_mmap+0x1ef/0xa00 mm/mmap.c:1300
 __mmput kernel/fork.c:1187 [inline]
 mmput+0xe0/0x430 kernel/fork.c:1210
 exit_mm kernel/exit.c:615 [inline]
 do_exit+0x833/0x2a50 kernel/exit.c:997
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0xd2/0x530 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x682/0x7f0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fda6feee0d9
Code: Unable to access opcode bytes at 0x7fda6feee0af.
RSP: 002b:00007fda6e9470e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fda70175fa8 RCX: 00007fda6feee0d9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fda70175fa8
RBP: 00007fda70175fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda70176038 R14: 00007ffe1f709330 R15: 00007ffe1f709418
 </TASK>
BUG: sleeping function called from invalid context at kernel/workqueue.c:4487
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 6027, name: syz.1.204
preempt_count: 102, expected: 0
RCU nest depth: 1, expected: 0
5 locks held by syz.1.204/6027:
 #0: ffff88813c1b67b8 (&mm->mmap_lock){++++}-{4:4}
, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
, at: exit_mmap+0x124/0xa00 mm/mmap.c:1284
 #1: 
ffffffff896e2bc0 (rcu_read_lock
){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
){....}-{1:3}, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290
 #2: ffff888124c97618 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}
, at: spin_lock include/linux/spinlock.h:342 [inline]
, at: pte_offset_map_lock+0x10f/0x320 mm/pgtable-generic.c:404
 #3: 
ffffffff896e2b00
 (rcu_read_lock_sched){....}-{1:2}
, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
, at: rcu_read_lock_sched include/linux/rcupdate.h:938 [inline]
, at: pfn_valid+0xbc/0x4a0 include/linux/mmzone.h:2270
 #4: 
ffffc900001a8ca0
 ((&vub300->inactivity_timer)){+.-.}-{0:0}
, at: call_timer_fn+0x11f/0x610 kernel/time/timer.c:1745
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 1 UID: 0 PID: 6027 Comm: syz.1.204 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 __might_resched.cold+0x1ec/0x232 kernel/sched/core.c:9197
 __cancel_work_sync kernel/workqueue.c:4487 [inline]
 cancel_delayed_work_sync+0xb8/0xf0 kernel/workqueue.c:4568
 mmc_free_host+0x19/0x30 drivers/mmc/core/host.c:700
 vub300_delete drivers/mmc/host/vub300.c:379 [inline]
 kref_put include/linux/kref.h:65 [inline]
 vub300_inactivity_timer_expired drivers/mmc/host/vub300.c:747 [inline]
 vub300_inactivity_timer_expired+0x42f/0x550 drivers/mmc/host/vub300.c:742
 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers+0x757/0xb00 kernel/time/timer.c:2374
 __run_timer_base kernel/time/timer.c:2386 [inline]
 __run_timer_base kernel/time/timer.c:2378 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2395
 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
 handle_softirqs+0x1dd/0x990 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x160/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:write_comp_data+0x40/0x90 kernel/kcov.c:246
Code: 4a 0b a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 80 6b cb 05 8b 87 44 16 00 00 85 c0 74 f1 8b 87 18 16 00 00 <83> f8 03 75 e6 48 8b 87 20 16 00 00 8b bf 1c 16 00 00 48 8b 30 48
RSP: 0018:ffffc900129f7480 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff82216c22
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff888113aa9e00
RBP: ffff88823ff5d4c0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000008
R13: 0000000000000001 R14: ffff888134aabab0 R15: 8000000131a0d067
 rcu_read_unlock_sched include/linux/rcupdate.h:960 [inline]
 pfn_valid+0x3e2/0x4a0 include/linux/mmzone.h:2280
 page_table_check_clear+0x21/0x540 mm/page_table_check.c:70
 __page_table_check_pte_clear+0x10f/0x120 mm/page_table_check.c:155
 page_table_check_pte_clear include/linux/page_table_check.h:55 [inline]
 ptep_get_and_clear_full arch/x86/include/asm/pgtable.h:1263 [inline]
 get_and_clear_full_ptes include/linux/pgtable.h:879 [inline]
 zap_present_folio_ptes mm/memory.c:1648 [inline]
 zap_present_ptes mm/memory.c:1730 [inline]
 do_zap_pte_range mm/memory.c:1832 [inline]
 zap_pte_range mm/memory.c:1934 [inline]
 zap_pmd_range mm/memory.c:2020 [inline]
 zap_pud_range mm/memory.c:2048 [inline]
 zap_p4d_range mm/memory.c:2069 [inline]
 __zap_vma_range+0x23f2/0x4000 mm/memory.c:2109
 unmap_vmas+0x299/0x5f0 mm/memory.c:2178
 exit_mmap+0x1ef/0xa00 mm/mmap.c:1300
 __mmput kernel/fork.c:1187 [inline]
 mmput+0xe0/0x430 kernel/fork.c:1210
 exit_mm kernel/exit.c:615 [inline]
 do_exit+0x833/0x2a50 kernel/exit.c:997
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0xd2/0x530 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x682/0x7f0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fda6feee0d9
Code: Unable to access opcode bytes at 0x7fda6feee0af.
RSP: 002b:00007fda6e9470e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fda70175fa8 RCX: 00007fda6feee0d9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fda70175fa8
RBP: 00007fda70175fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda70176038 R14: 00007ffe1f709330 R15: 00007ffe1f709418
 </TASK>

=============================
WARNING: suspicious RCU usage
syzkaller #0 Tainted: G        W          
-----------------------------
kernel/rcu/srcutree.c:1483 Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
5 locks held by syz.1.204/6027:
 #0: ffff88813c1b67b8 (
&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x124/0xa00 mm/mmap.c:1284
 #1: ffffffff896e2bc0 (
rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290
 #2: ffff888124c97618 (
ptlock_ptr(ptdesc)#2){+.+.}-{3:3}
, at: spin_lock include/linux/spinlock.h:342 [inline]
, at: pte_offset_map_lock+0x10f/0x320 mm/pgtable-generic.c:404
 #3: 
ffffffff896e2b00 (rcu_read_lock_sched
){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
){....}-{1:2}, at: rcu_read_lock_sched include/linux/rcupdate.h:938 [inline]
){....}-{1:2}, at: pfn_valid+0xbc/0x4a0 include/linux/mmzone.h:2270
 #4: 
ffffc900001a8ca0 ((&vub300->inactivity_timer)
){+.-.}-{0:0}, at: call_timer_fn+0x11f/0x610 kernel/time/timer.c:1745

stack backtrace:
CPU: 1 UID: 0 PID: 6027 Comm: syz.1.204 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 lockdep_rcu_suspicious.cold+0x4f/0xb1 kernel/locking/lockdep.c:6876
 __synchronize_srcu+0x29d/0x300 kernel/rcu/srcutree.c:1483
 wakeup_source_remove drivers/base/power/wakeup.c:201 [inline]
 wakeup_source_unregister.part.0+0x12c/0x540 drivers/base/power/wakeup.c:237
 wakeup_source_unregister+0x1f/0x30 drivers/base/power/wakeup.c:236
 mmc_host_classdev_release+0x42/0x120 drivers/mmc/core/host.c:69
 device_release+0xd2/0x270 drivers/base/core.c:2636
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1f7/0x640 lib/kobject.c:737
 put_device+0x1f/0x30 drivers/base/core.c:3880
 vub300_delete drivers/mmc/host/vub300.c:379 [inline]
 kref_put include/linux/kref.h:65 [inline]
 vub300_inactivity_timer_expired drivers/mmc/host/vub300.c:747 [inline]
 vub300_inactivity_timer_expired+0x42f/0x550 drivers/mmc/host/vub300.c:742
 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers+0x757/0xb00 kernel/time/timer.c:2374
 __run_timer_base kernel/time/timer.c:2386 [inline]
 __run_timer_base kernel/time/timer.c:2378 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2395
 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
 handle_softirqs+0x1dd/0x990 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x160/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:write_comp_data+0x40/0x90 kernel/kcov.c:246
Code: 4a 0b a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 80 6b cb 05 8b 87 44 16 00 00 85 c0 74 f1 8b 87 18 16 00 00 <83> f8 03 75 e6 48 8b 87 20 16 00 00 8b bf 1c 16 00 00 48 8b 30 48
RSP: 0018:ffffc900129f7480 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff82216c22
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff888113aa9e00
RBP: ffff88823ff5d4c0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000008
R13: 0000000000000001 R14: ffff888134aabab0 R15: 8000000131a0d067
 rcu_read_unlock_sched include/linux/rcupdate.h:960 [inline]
 pfn_valid+0x3e2/0x4a0 include/linux/mmzone.h:2280
 page_table_check_clear+0x21/0x540 mm/page_table_check.c:70
 __page_table_check_pte_clear+0x10f/0x120 mm/page_table_check.c:155
 page_table_check_pte_clear include/linux/page_table_check.h:55 [inline]
 ptep_get_and_clear_full arch/x86/include/asm/pgtable.h:1263 [inline]
 get_and_clear_full_ptes include/linux/pgtable.h:879 [inline]
 zap_present_folio_ptes mm/memory.c:1648 [inline]
 zap_present_ptes mm/memory.c:1730 [inline]
 do_zap_pte_range mm/memory.c:1832 [inline]
 zap_pte_range mm/memory.c:1934 [inline]
 zap_pmd_range mm/memory.c:2020 [inline]
 zap_pud_range mm/memory.c:2048 [inline]
 zap_p4d_range mm/memory.c:2069 [inline]
 __zap_vma_range+0x23f2/0x4000 mm/memory.c:2109
 unmap_vmas+0x299/0x5f0 mm/memory.c:2178
 exit_mmap+0x1ef/0xa00 mm/mmap.c:1300
 __mmput kernel/fork.c:1187 [inline]
 mmput+0xe0/0x430 kernel/fork.c:1210
 exit_mm kernel/exit.c:615 [inline]
 do_exit+0x833/0x2a50 kernel/exit.c:997
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0xd2/0x530 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x682/0x7f0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fda6feee0d9
Code: Unable to access opcode bytes at 0x7fda6feee0af.
RSP: 002b:00007fda6e9470e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fda70175fa8 RCX: 00007fda6feee0d9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fda70175fa8
RBP: 00007fda70175fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda70176038 R14: 00007ffe1f709330 R15: 00007ffe1f709418
 </TASK>
BUG: sleeping function called from invalid context at kernel/rcu/srcutree.c:1491
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 6027, name: syz.1.204
preempt_count: 102, expected: 0
RCU nest depth: 1, expected: 0
5 locks held by syz.1.204/6027:
 #0: ffff88813c1b67b8 (&mm->mmap_lock){++++}-{4:4}
, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
, at: exit_mmap+0x124/0xa00 mm/mmap.c:1284
 #1: 
ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290
 #2: ffff888124c97618 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
 #2: ffff888124c97618 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x10f/0x320 mm/pgtable-generic.c:404
 #3: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}
, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
, at: rcu_read_lock_sched include/linux/rcupdate.h:938 [inline]
, at: pfn_valid+0xbc/0x4a0 include/linux/mmzone.h:2270
 #4: ffffc900001a8ca0 ((&vub300->inactivity_timer)){+.-.}-{0:0}
, at: call_timer_fn+0x11f/0x610 kernel/time/timer.c:1745
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 1 UID: 0 PID: 6027 Comm: syz.1.204 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 __might_resched.cold+0x1ec/0x232 kernel/sched/core.c:9197
 __synchronize_srcu+0x13c/0x300 kernel/rcu/srcutree.c:1491
 wakeup_source_remove drivers/base/power/wakeup.c:201 [inline]
 wakeup_source_unregister.part.0+0x12c/0x540 drivers/base/power/wakeup.c:237
 wakeup_source_unregister+0x1f/0x30 drivers/base/power/wakeup.c:236
 mmc_host_classdev_release+0x42/0x120 drivers/mmc/core/host.c:69
 device_release+0xd2/0x270 drivers/base/core.c:2636
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1f7/0x640 lib/kobject.c:737
 put_device+0x1f/0x30 drivers/base/core.c:3880
 vub300_delete drivers/mmc/host/vub300.c:379 [inline]
 kref_put include/linux/kref.h:65 [inline]
 vub300_inactivity_timer_expired drivers/mmc/host/vub300.c:747 [inline]
 vub300_inactivity_timer_expired+0x42f/0x550 drivers/mmc/host/vub300.c:742
 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers+0x757/0xb00 kernel/time/timer.c:2374
 __run_timer_base kernel/time/timer.c:2386 [inline]
 __run_timer_base kernel/time/timer.c:2378 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2395
 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
 handle_softirqs+0x1dd/0x990 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x160/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:write_comp_data+0x40/0x90 kernel/kcov.c:246
Code: 4a 0b a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 80 6b cb 05 8b 87 44 16 00 00 85 c0 74 f1 8b 87 18 16 00 00 <83> f8 03 75 e6 48 8b 87 20 16 00 00 8b bf 1c 16 00 00 48 8b 30 48
RSP: 0018:ffffc900129f7480 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff82216c22
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff888113aa9e00
RBP: ffff88823ff5d4c0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000008
R13: 0000000000000001 R14: ffff888134aabab0 R15: 8000000131a0d067
 rcu_read_unlock_sched include/linux/rcupdate.h:960 [inline]
 pfn_valid+0x3e2/0x4a0 include/linux/mmzone.h:2280
 page_table_check_clear+0x21/0x540 mm/page_table_check.c:70
 __page_table_check_pte_clear+0x10f/0x120 mm/page_table_check.c:155
 page_table_check_pte_clear include/linux/page_table_check.h:55 [inline]
 ptep_get_and_clear_full arch/x86/include/asm/pgtable.h:1263 [inline]
 get_and_clear_full_ptes include/linux/pgtable.h:879 [inline]
 zap_present_folio_ptes mm/memory.c:1648 [inline]
 zap_present_ptes mm/memory.c:1730 [inline]
 do_zap_pte_range mm/memory.c:1832 [inline]
 zap_pte_range mm/memory.c:1934 [inline]
 zap_pmd_range mm/memory.c:2020 [inline]
 zap_pud_range mm/memory.c:2048 [inline]
 zap_p4d_range mm/memory.c:2069 [inline]
 __zap_vma_range+0x23f2/0x4000 mm/memory.c:2109
 unmap_vmas+0x299/0x5f0 mm/memory.c:2178
 exit_mmap+0x1ef/0xa00 mm/mmap.c:1300
 __mmput kernel/fork.c:1187 [inline]
 mmput+0xe0/0x430 kernel/fork.c:1210
 exit_mm kernel/exit.c:615 [inline]
 do_exit+0x833/0x2a50 kernel/exit.c:997
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0xd2/0x530 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x682/0x7f0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fda6feee0d9
Code: Unable to access opcode bytes at 0x7fda6feee0af.
RSP: 002b:00007fda6e9470e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fda70175fa8 RCX: 00007fda6feee0d9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fda70175fa8
RBP: 00007fda70175fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda70176038 R14: 00007ffe1f709330 R15: 00007ffe1f709418
 </TASK>
ODEBUG: object ffffc900001a8a70 is NOT on stack ffffc900129f0000, but annotated.

======================================================
----------------
Code disassembly (best guess):
   0:	4a 0b a9 00 01 ff 00 	rex.WX or 0xff0100(%rcx),%rbp
   7:	74 1b                	je     0x24
   9:	f6 c4 01             	test   $0x1,%ah
   c:	74 07                	je     0x15
   e:	a9 00 00 ff 00       	test   $0xff0000,%eax
  13:	74 05                	je     0x1a
  15:	e9 80 6b cb 05       	jmp    0x5cb6b9a
  1a:	8b 87 44 16 00 00    	mov    0x1644(%rdi),%eax
  20:	85 c0                	test   %eax,%eax
  22:	74 f1                	je     0x15
  24:	8b 87 18 16 00 00    	mov    0x1618(%rdi),%eax
* 2a:	83 f8 03             	cmp    $0x3,%eax <-- trapping instruction
  2d:	75 e6                	jne    0x15
  2f:	48 8b 87 20 16 00 00 	mov    0x1620(%rdi),%rax
  36:	8b bf 1c 16 00 00    	mov    0x161c(%rdi),%edi
  3c:	48 8b 30             	mov    (%rax),%rsi
  3f:	48                   	rex.W

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/15 04:20 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: suspicious RCU usage in cancel_delayed_work_sync
2026/08/14 16:56 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: suspicious RCU usage in cancel_delayed_work_sync
2026/08/14 05:43 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 05abeffcc27e b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: suspicious RCU usage in cancel_delayed_work_sync
2026/08/14 05:27 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 05abeffcc27e b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: suspicious RCU usage in cancel_delayed_work_sync
2026/08/13 20:33 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 5d5fd841c346 b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: suspicious RCU usage in cancel_delayed_work_sync
* Struck through repros no longer work on HEAD.