WARNING: suspicious RCU usage in cancel_delayed_work_sync

Status: upstream: reported on 2026/08/14 15:11
Subsystems: mmc
[Documentation on labels]
Reported-by: syzbot+9c1988bc953fca2086a3@syzkaller.appspotmail.com
First crash: 1d04h, last: 7h53m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
7f49902c assessment-security 🏃 WARNING: suspicious RCU usage in cancel_delayed_work_sync 2026/08/15 00:46 2026/08/15 00:46 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
9 locks held by syz-executor/2977:
 #0: ffffffff89823d10 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
 #0: ffffffff89823d10 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm kernel/fork.c:1595 [inline]
 #0: ffffffff89823d10 (dup_mmap_sem){.+.+}-{0:0}, at: copy_process+0x498b/0x7dd0 kernel/fork.c:2289
 #1: ffff888123b27438 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:554 [inline]
 #1: ffff888123b27438 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x11f/0x1f60 mm/mmap.c:1739
 #2: ffff888116959038 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:544 [inline]
 #2: ffff888116959038 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x1ba/0x1f60 mm/mmap.c:1746
 #3: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #3: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #3: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290
 #4: ffff888119ac4258 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
 #4: ffff888119ac4258 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x10f/0x320 mm/pgtable-generic.c:404
 #5: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #5: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #5: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pte_range mm/memory.c:1272 [inline]
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pmd_range mm/memory.c:1408 [inline]
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pud_range mm/memory.c:1445 [inline]
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_p4d_range mm/memory.c:1469 [inline]
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_page_range+0xcc2/0x56a0 mm/memory.c:1555
 #7: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #7: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: rcu_read_lock_sched include/linux/rcupdate.h:938 [inline]
 #7: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: pfn_valid+0xbc/0x4a0 include/linux/mmzone.h:2270
 #8: ffffc90000007ca0 ((&vub300->inactivity_timer)){+.-.}-{0:0}, at: call_timer_fn+0x11f/0x610 kernel/time/timer.c:1745

stack backtrace:
CPU: 0 UID: 0 PID: 2977 Comm: syz-executor 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:lockdep_enabled kernel/locking/lockdep.c:124 [inline]
RIP: 0010:lock_release+0x75/0x310 kernel/locking/lockdep.c:5881
Code: 63 09 45 85 c0 0f 84 48 01 00 00 65 8b 05 c3 d1 6e 0b 85 c0 0f 85 39 01 00 00 65 4c 8b 25 bb 8e 6e 0b 41 8b bc 24 54 0b 00 00 <85> ff 0f 85 21 01 00 00 48 81 3b 40 40 04 8d 0f 84 14 01 00 00 9c
RSP: 0018:ffffc9000166f408 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff896e2b00 RCX: ffffffff82216c22
RDX: 0000000000000000 RSI: ffffffff87b15680 RDI: 0000000000000000
RBP: ffffffff82216a23 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888122721e00
R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000000
 rcu_lock_release include/linux/rcupdate.h:310 [inline]
 rcu_read_unlock_sched include/linux/rcupdate.h:962 [inline]
 pfn_valid+0x1e8/0x4a0 include/linux/mmzone.h:2280
 page_table_check_set+0x25/0x580 mm/page_table_check.c:105
 __page_table_check_ptes_set+0x217/0x270 mm/page_table_check.c:223
 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline]
 set_ptes include/linux/pgtable.h:447 [inline]
 __copy_present_ptes mm/memory.c:1118 [inline]
 copy_present_ptes mm/memory.c:1197 [inline]
 copy_pte_range mm/memory.c:1320 [inline]
 copy_pmd_range mm/memory.c:1408 [inline]
 copy_pud_range mm/memory.c:1445 [inline]
 copy_p4d_range mm/memory.c:1469 [inline]
 copy_page_range+0x1c87/0x56a0 mm/memory.c:1555
 dup_mmap+0xcd8/0x1f60 mm/mmap.c:1840
 dup_mm kernel/fork.c:1543 [inline]
 copy_mm kernel/fork.c:1595 [inline]
 copy_process+0x4996/0x7dd0 kernel/fork.c:2289
 kernel_clone+0x176/0x9d0 kernel/fork.c:2748
 __do_sys_clone+0xd9/0x120 kernel/fork.c:2889
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0x7f0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2639fa6b52
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffca22a86b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffca22a86b0 RCX: 00007f2639fa6b52
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffca22a883c R08: 0000000000000000 R09: 0000000000000001
R10: 000055558011b7d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 0000000000028ae8 R15: 00007ffca22a8890
 </TASK>
BUG: sleeping function called from invalid context at kernel/workqueue.c:4487
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2977, name: syz-executor
preempt_count: 103, expected: 0
RCU nest depth: 2, expected: 0
9 locks held by syz-executor/2977:
 #0: ffffffff89823d10
 (
dup_mmap_sem){.+.+}-{0:0}
, at: dup_mm kernel/fork.c:1542 [inline]
, at: copy_mm kernel/fork.c:1595 [inline]
, at: copy_process+0x498b/0x7dd0 kernel/fork.c:2289
 #1: ffff888123b27438
 (
&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:554 [inline]
&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x11f/0x1f60 mm/mmap.c:1739
 #2: ffff888116959038 (&mm->mmap_lock
/1){+.+.}-{4:4}
, at: mmap_write_lock_nested include/linux/mmap_lock.h:544 [inline]
, at: dup_mmap+0x1ba/0x1f60 mm/mmap.c:1746
 #3: 
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
 #4: 
ffff888119ac4258
 (
ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x10f/0x320 mm/pgtable-generic.c:404
 #5: 
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
 #6: ffff888127c20918 (
ptlock_ptr(ptdesc)
#2/1){+.+.}-{3:3}
, at: copy_pte_range mm/memory.c:1272 [inline]
, at: copy_pmd_range mm/memory.c:1408 [inline]
, at: copy_pud_range mm/memory.c:1445 [inline]
, at: copy_p4d_range mm/memory.c:1469 [inline]
, at: copy_page_range+0xcc2/0x56a0 mm/memory.c:1555
 #7: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #7: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: rcu_read_lock_sched include/linux/rcupdate.h:938 [inline]
 #7: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: pfn_valid+0xbc/0x4a0 include/linux/mmzone.h:2270
 #8: ffffc90000007ca0 ((&vub300->inactivity_timer)){+.-.}-{0:0}, at: call_timer_fn+0x11f/0x610 kernel/time/timer.c:1745
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 0 UID: 0 PID: 2977 Comm: syz-executor 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:lockdep_enabled kernel/locking/lockdep.c:124 [inline]
RIP: 0010:lock_release+0x75/0x310 kernel/locking/lockdep.c:5881
Code: 63 09 45 85 c0 0f 84 48 01 00 00 65 8b 05 c3 d1 6e 0b 85 c0 0f 85 39 01 00 00 65 4c 8b 25 bb 8e 6e 0b 41 8b bc 24 54 0b 00 00 <85> ff 0f 85 21 01 00 00 48 81 3b 40 40 04 8d 0f 84 14 01 00 00 9c
RSP: 0018:ffffc9000166f408 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff896e2b00 RCX: ffffffff82216c22
RDX: 0000000000000000 RSI: ffffffff87b15680 RDI: 0000000000000000
RBP: ffffffff82216a23 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888122721e00
R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000000
 rcu_lock_release include/linux/rcupdate.h:310 [inline]
 rcu_read_unlock_sched include/linux/rcupdate.h:962 [inline]
 pfn_valid+0x1e8/0x4a0 include/linux/mmzone.h:2280
 page_table_check_set+0x25/0x580 mm/page_table_check.c:105
 __page_table_check_ptes_set+0x217/0x270 mm/page_table_check.c:223
 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline]
 set_ptes include/linux/pgtable.h:447 [inline]
 __copy_present_ptes mm/memory.c:1118 [inline]
 copy_present_ptes mm/memory.c:1197 [inline]
 copy_pte_range mm/memory.c:1320 [inline]
 copy_pmd_range mm/memory.c:1408 [inline]
 copy_pud_range mm/memory.c:1445 [inline]
 copy_p4d_range mm/memory.c:1469 [inline]
 copy_page_range+0x1c87/0x56a0 mm/memory.c:1555
 dup_mmap+0xcd8/0x1f60 mm/mmap.c:1840
 dup_mm kernel/fork.c:1543 [inline]
 copy_mm kernel/fork.c:1595 [inline]
 copy_process+0x4996/0x7dd0 kernel/fork.c:2289
 kernel_clone+0x176/0x9d0 kernel/fork.c:2748
 __do_sys_clone+0xd9/0x120 kernel/fork.c:2889
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0x7f0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2639fa6b52
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffca22a86b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffca22a86b0 RCX: 00007f2639fa6b52
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffca22a883c R08: 0000000000000000 R09: 0000000000000001
R10: 000055558011b7d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 0000000000028ae8 R15: 00007ffca22a8890
 </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
9 locks held by syz-executor/2977:
 #0: ffffffff89823d10 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
 #0: ffffffff89823d10 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm kernel/fork.c:1595 [inline]
 #0: ffffffff89823d10 (dup_mmap_sem){.+.+}-{0:0}, at: copy_process+0x498b/0x7dd0 kernel/fork.c:2289
 #1: ffff888123b27438 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:554 [inline]
 #1: ffff888123b27438 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x11f/0x1f60 mm/mmap.c:1739
 #2: ffff888116959038 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:544 [inline]
 #2: ffff888116959038 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x1ba/0x1f60 mm/mmap.c:1746
 #3: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #3: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #3: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290
 #4: ffff888119ac4258 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
 #4: ffff888119ac4258 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x10f/0x320 mm/pgtable-generic.c:404
 #5: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #5: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #5: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pte_range mm/memory.c:1272 [inline]
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pmd_range mm/memory.c:1408 [inline]
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pud_range mm/memory.c:1445 [inline]
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_p4d_range mm/memory.c:1469 [inline]
 #6: ffff888127c20918 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_page_range+0xcc2/0x56a0 mm/memory.c:1555
 #7: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #7: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: rcu_read_lock_sched include/linux/rcupdate.h:938 [inline]
 #7: ffffffff896e2b00 (rcu_read_lock_sched){....}-{1:2}, at: pfn_valid+0xbc/0x4a0 include/linux/mmzone.h:2270
 #8: ffffc90000007ca0 ((&vub300->inactivity_timer)){+.-.}-{0:0}, at: call_timer_fn+0x11f/0x610 kernel/time/timer.c:1745

stack backtrace:
CPU: 0 UID: 0 PID: 2977 Comm: syz-executor 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:lockdep_enabled kernel/locking/lockdep.c:124 [inline]
RIP: 0010:lock_release+0x75/0x310 kernel/locking/lockdep.c:5881
Code: 63 09 45 85 c0 0f 84 48 01 00 00 65 8b 05 c3 d1 6e 0b 85 c0 0f 85 39 01 00 00 65 4c 8b 25 bb 8e 6e 0b 41 8b bc 24 54 0b 00 00 <85> ff 0f 85 21 01 00 00 48 81 3b 40 40 04 8d 0f 84 14 01 00 00 9c
RSP: 0018:ffffc9000166f408 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff896e2b00 RCX: ffffffff82216c22
RDX: 0000000000000000 RSI: ffffffff87b15680 RDI: 0000000000000000
RBP: ffffffff82216a23 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888122721e00
R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000000
 rcu_lock_release include/linux/rcupdate.h:310 [inline]
 rcu_read_unlock_sched include/linux/rcupdate.h:962 [inline]
 pfn_valid+0x1e8/0x4a0 include/linux/mmzone.h:2280
 page_table_check_set+0x25/0x580 mm/page_table_check.c:105
 __page_table_check_ptes_set+0x217/0x270 mm/page_table_check.c:223
 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline]
 set_ptes include/linux/pgtable.h:447 [inline]
 __copy_present_ptes mm/memory.c:1118 [inline]
 copy_present_ptes mm/memory.c:1197 [inline]
 copy_pte_range mm/memory.c:1320 [inline]
 copy_pmd_range mm/memory.c:1408 [inline]
 copy_pud_range mm/memory.c:1445 [inline]
 copy_p4d_range mm/memory.c:1469 [inline]
 copy_page_range+0x1c87/0x56a0 mm/memory.c:1555
 dup_mmap+0xcd8/0x1f60 mm/mmap.c:1840
 dup_mm kernel/fork.c:1543 [inline]
 copy_mm kernel/fork.c:1595 [inline]
 copy_process+0x4996/0x7dd0 kernel/fork.c:2289
 kernel_clone+0x176/0x9d0 kernel/fork.c:2748
 __do_sys_clone+0xd9/0x120 kernel/fork.c:2889
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0x7f0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2639fa6b52
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffca22a86b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffca22a86b0 RCX: 00007f2639fa6b52
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffca22a883c R08: 0000000000000000 R09: 0000000000000001
R10: 000055558011b7d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 0000000000028ae8 R15: 00007ffca22a8890
 </TASK>
BUG: sleeping function called from invalid context at kernel/rcu/srcutree.c:1491
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2977, name: syz-executor
preempt_count: 103, expected: 0
RCU nest depth: 2, expected: 0
9 locks held by syz-executor/2977:
 #0: 
ffffffff89823d10 (
dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
dup_mmap_sem){.+.+}-{0:0}, at: copy_mm kernel/fork.c:1595 [inline]
dup_mmap_sem){.+.+}-{0:0}, at: copy_process+0x498b/0x7dd0 kernel/fork.c:2289
 #1: ffff888123b27438 (&mm->mmap_lock){++++}-{4:4}
, at: mmap_write_lock_killable include/linux/mmap_lock.h:554 [inline]
, at: dup_mmap+0x11f/0x1f60 mm/mmap.c:1739
 #2: 
ffff888116959038
 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:544 [inline]
 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x1ba/0x1f60 mm/mmap.c:1746
 #3: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #3: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #3: ffffffff896e2bc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x300 mm/pgtable-generic.c:290
 #4: ffff888119ac4258 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
 #4: ffff888119ac4258 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x10f/0x320 mm/pgtable-generic.c:404
 #5: 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
 #6: ffff888127c20918
 (
ptlock_ptr(ptdesc)
#2/1){+.+.}-{3:3}
, at: copy_pte_range mm/memory.c:1272 [inline]
, at: copy_pmd_range mm/memory.c:1408 [inline]
, at: copy_pud_range mm/memory.c:1445 [inline]
, at: copy_p4d_range mm/memory.c:1469 [inline]
, at: copy_page_range+0xcc2/0x56a0 mm/memory.c:1555
 #7: ffffffff896e2b00 (
rcu_read_lock_sched){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock_sched){....}-{1:2}, at: rcu_read_lock_sched include/linux/rcupdate.h:938 [inline]
rcu_read_lock_sched){....}-{1:2}, at: pfn_valid+0xbc/0x4a0 include/linux/mmzone.h:2270
 #8: ffffc90000007ca0
 (
(&vub300->inactivity_timer)
){+.-.}-{0:0}, at: call_timer_fn+0x11f/0x610 kernel/time/timer.c:1745
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 0 UID: 0 PID: 2977 Comm: syz-executor 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:lockdep_enabled kernel/locking/lockdep.c:124 [inline]
RIP: 0010:lock_release+0x75/0x310 kernel/locking/lockdep.c:5881
Code: 63 09 45 85 c0 0f 84 48 01 00 00 65 8b 05 c3 d1 6e 0b 85 c0 0f 85 39 01 00 00 65 4c 8b 25 bb 8e 6e 0b 41 8b bc 24 54 0b 00 00 <85> ff 0f 85 21 01 00 00 48 81 3b 40 40 04 8d 0f 84 14 01 00 00 9c
RSP: 0018:ffffc9000166f408 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff896e2b00 RCX: ffffffff82216c22
RDX: 0000000000000000 RSI: ffffffff87b15680 RDI: 0000000000000000
RBP: ffffffff82216a23 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888122721e00
R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000000
 rcu_lock_release include/linux/rcupdate.h:310 [inline]
 rcu_read_unlock_sched include/linux/rcupdate.h:962 [inline]
 pfn_valid+0x1e8/0x4a0 include/linux/mmzone.h:2280
 page_table_check_set+0x25/0x580 mm/page_table_check.c:105
 __page_table_check_ptes_set+0x217/0x270 mm/page_table_check.c:223
 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline]
 set_ptes include/linux/pgtable.h:447 [inline]
 __copy_present_ptes mm/memory.c:1118 [inline]
 copy_present_ptes mm/memory.c:1197 [inline]
 copy_pte_range mm/memory.c:1320 [inline]
 copy_pmd_range mm/memory.c:1408 [inline]
 copy_pud_range mm/memory.c:1445 [inline]
 copy_p4d_range mm/memory.c:1469 [inline]
 copy_page_range+0x1c87/0x56a0 mm/memory.c:1555
 dup_mmap+0xcd8/0x1f60 mm/mmap.c:1840
 dup_mm kernel/fork.c:1543 [inline]
 copy_mm kernel/fork.c:1595 [inline]
 copy_process+0x4996/0x7dd0 kernel/fork.c:2289
 kernel_clone+0x176/0x9d0 kernel/fork.c:2748
 __do_sys_clone+0xd9/0x120 kernel/fork.c:2889
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0x7f0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2639fa6b52
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffca22a86b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffca22a86b0 RCX: 00007f2639fa6b52
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffca22a883c R08: 0000000000000000 R09: 0000000000000001
R10: 000055558011b7d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 0000000000028ae8 R15: 00007ffca22a8890
 </TASK>
ODEBUG: object ffffc90000007a70 is NOT on stack ffffc90001668000, but annotated.

======================================================
----------------
Code disassembly (best guess):
   0:	63 09                	movsxd (%rcx),%ecx
   2:	45 85 c0             	test   %r8d,%r8d
   5:	0f 84 48 01 00 00    	je     0x153
   b:	65 8b 05 c3 d1 6e 0b 	mov    %gs:0xb6ed1c3(%rip),%eax        # 0xb6ed1d5
  12:	85 c0                	test   %eax,%eax
  14:	0f 85 39 01 00 00    	jne    0x153
  1a:	65 4c 8b 25 bb 8e 6e 	mov    %gs:0xb6e8ebb(%rip),%r12        # 0xb6e8edd
  21:	0b
  22:	41 8b bc 24 54 0b 00 	mov    0xb54(%r12),%edi
  29:	00
* 2a:	85 ff                	test   %edi,%edi <-- trapping instruction
  2c:	0f 85 21 01 00 00    	jne    0x153
  32:	48 81 3b 40 40 04 8d 	cmpq   $0xffffffff8d044040,(%rbx)
  39:	0f 84 14 01 00 00    	je     0x153
  3f:	9c                   	pushf

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.