------------[ cut here ]------------ WARNING: CPU: 1 PID: 59 at lib/percpu-refcount.c:112 __percpu_ref_exit+0x98/0x100 lib/percpu-refcount.c:112 Modules linked in: CPU: 1 PID: 59 Comm: kworker/u4:1 Not tainted 5.10.45 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Workqueue: events_unbound io_ring_exit_work RIP: 0010:__percpu_ref_exit+0x98/0x100 lib/percpu-refcount.c:112 Code: ff 49 8d 7c 24 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 61 49 83 7c 24 10 00 74 07 e8 78 2f 52 ff <0f> 0b e8 71 2f 52 ff 48 89 ef e8 79 7f 6d ff 48 89 da 48 b8 00 00 RSP: 0018:ffff88800c39fca0 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff88800e02c000 RCX: ffffffff81ed5be8 RDX: ffff88800c390000 RSI: ffffffff81ed5c48 RDI: ffff888021991f90 RBP: 0000607f92e0eba0 R08: 0000000000000001 R09: ffffffff864f06b7 R10: 0000000000000000 R11: 0000000000000001 R12: ffff888021991f80 R13: ffff88800e02c000 R14: ffff888021991f80 R15: ffff888016016520 FS: 0000000000000000(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3ee3c4e718 CR3: 000000000eb5e000 CR4: 0000000000350ee0 Call Trace: percpu_ref_exit+0x3b/0x140 lib/percpu-refcount.c:133 io_ring_ctx_free fs/io_uring.c:8460 [inline] io_ring_exit_work+0x41a/0x640 fs/io_uring.c:8536 process_one_work+0x9a9/0x1590 kernel/workqueue.c:2270 worker_thread+0x61d/0x1310 kernel/workqueue.c:2416 kthread+0x38f/0x470 kernel/kthread.c:292 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:296 irq event stamp: 1100585 hardirqs last enabled at (1100595): [] console_unlock+0x929/0xb30 kernel/printk/printk.c:2552 hardirqs last disabled at (1100604): [] console_unlock+0x835/0xb30 kernel/printk/printk.c:2467 softirqs last enabled at (1100618): [] asm_call_irq_on_stack+0x12/0x20 softirqs last disabled at (1100613): [] asm_call_irq_on_stack+0x12/0x20 ---[ end trace 266a8ec2f43711e1 ]--- ================================================================== BUG: KASAN: use-after-free in rcu_cblist_dequeue+0xa4/0xe0 kernel/rcu/rcu_segcblist.c:75 Read of size 8 at addr ffff888021991fa0 by task syz-fuzzer/373 CPU: 1 PID: 373 Comm: syz-fuzzer Tainted: G W 5.10.45 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 print_address_description.constprop.0+0x1c/0x210 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x37/0x7c mm/kasan/report.c:562 rcu_cblist_dequeue+0xa4/0xe0 kernel/rcu/rcu_segcblist.c:75 rcu_do_batch kernel/rcu/tree.c:2474 [inline] rcu_core+0x4a3/0x1640 kernel/rcu/tree.c:2719 __do_softirq+0x1b8/0x85f kernel/softirq.c:298 asm_call_irq_on_stack+0x12/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0x80/0xa0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x110/0x1a0 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x43/0xa0 arch/x86/kernel/apic/apic.c:1095 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:644 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:49 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:__schedule+0x1bc/0x1e70 kernel/sched/core.c:4425 Code: c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 8a 16 00 00 83 3d 71 ec 80 01 02 0f 84 a2 13 00 00 0f 1f 44 00 00 9c 58 f6 c4 02 0f 85 24 0d 00 00 8b bd 44 ff ff ff e8 0f a4 69 fd 4c RSP: 0018:ffff888021a87bb0 EFLAGS: 00000293 RAX: 0000000000000293 RBX: 0000000000000000 RCX: 1ffffffff0a89e40 RDX: 0000000000000000 RSI: ffffffff83c4231b RDI: ffffffff84df63e0 RBP: ffff888021a87c80 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88806cf33180 R13: ffff8880161b1940 R14: 0000000000033180 R15: 0000000000000000 schedule+0xcb/0x270 kernel/sched/core.c:4603 freezable_schedule include/linux/freezer.h:172 [inline] do_nanosleep+0x1b1/0x670 kernel/time/hrtimer.c:1896 hrtimer_nanosleep+0x25c/0x680 kernel/time/hrtimer.c:1949 __do_sys_nanosleep kernel/time/hrtimer.c:1983 [inline] __se_sys_nanosleep kernel/time/hrtimer.c:1970 [inline] __x64_sys_nanosleep+0x1dc/0x260 kernel/time/hrtimer.c:1970 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x465f2d Code: 8b 44 24 20 b9 40 42 0f 00 f7 f1 48 89 04 24 b8 e8 03 00 00 f7 e2 48 89 44 24 08 48 89 e7 be 00 00 00 00 b8 23 00 00 00 0f 05 <48> 8b 6c 24 10 48 83 c4 18 c3 cc cc cc cc cc cc cc cc cc b8 ba 00 RSP: 002b:000000c00003ff18 EFLAGS: 00000212 ORIG_RAX: 0000000000000023 RAX: ffffffffffffffda RBX: 0000000000000014 RCX: 0000000000465f2d RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000c00003ff18 RBP: 000000c00003ff28 R08: 000000000001e8f5 R09: 00007ffe42bb4090 R10: 00000000000b5ba6 R11: 0000000000000212 R12: 0000000000438880 R13: 0000000000000000 R14: 0000000000b5838c R15: 0000000000000000 Allocated by task 6253: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] percpu_ref_init+0xd8/0x390 lib/percpu-refcount.c:75 io_ring_ctx_alloc fs/io_uring.c:1203 [inline] io_uring_create fs/io_uring.c:9398 [inline] io_uring_setup+0x665/0x2fe0 fs/io_uring.c:9541 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 59: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0x110/0x150 mm/kasan/common.c:422 slab_free_hook mm/slub.c:1541 [inline] slab_free_freelist_hook+0x64/0x150 mm/slub.c:1574 slab_free mm/slub.c:3139 [inline] kfree+0xca/0x380 mm/slub.c:4121 percpu_ref_exit+0xf7/0x140 lib/percpu-refcount.c:144 io_ring_ctx_free fs/io_uring.c:8460 [inline] io_ring_exit_work+0x41a/0x640 fs/io_uring.c:8536 process_one_work+0x9a9/0x1590 kernel/workqueue.c:2270 worker_thread+0x61d/0x1310 kernel/workqueue.c:2416 kthread+0x38f/0x470 kernel/kthread.c:292 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:296 Last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x9e/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2961 [inline] call_rcu+0x8a/0xa20 kernel/rcu/tree.c:3035 __percpu_ref_switch_to_atomic lib/percpu-refcount.c:226 [inline] __percpu_ref_switch_mode+0x3ba/0x810 lib/percpu-refcount.c:273 percpu_ref_kill_and_confirm+0x8a/0x180 lib/percpu-refcount.c:387 percpu_ref_kill include/linux/percpu-refcount.h:149 [inline] io_ring_ctx_wait_and_kill+0x33/0x530 fs/io_uring.c:8549 io_uring_release+0x3e/0x50 fs/io_uring.c:8593 __fput+0x285/0x980 fs/file_table.c:281 task_work_run+0xe2/0x1a0 kernel/task_work.c:151 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xc1b/0x2780 kernel/exit.c:811 do_group_exit+0x125/0x310 kernel/exit.c:908 get_signal+0x469/0x2200 kernel/signal.c:2758 arch_do_signal+0x88/0x1a90 arch/x86/kernel/signal.c:789 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0xf7/0x160 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x38/0x230 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Second to last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x9e/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2961 [inline] call_rcu+0x8a/0xa20 kernel/rcu/tree.c:3035 __percpu_ref_switch_to_atomic lib/percpu-refcount.c:226 [inline] __percpu_ref_switch_mode+0x3ba/0x810 lib/percpu-refcount.c:273 percpu_ref_kill_and_confirm+0x8a/0x180 lib/percpu-refcount.c:387 percpu_ref_kill include/linux/percpu-refcount.h:149 [inline] __io_uring_register fs/io_uring.c:9736 [inline] __do_sys_io_uring_register+0x4eb/0x3f50 fs/io_uring.c:9877 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff888021991f80 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 32 bytes inside of 64-byte region [ffff888021991f80, ffff888021991fc0) The buggy address belongs to the page: page:00000000fd518354 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21991 flags: 0x100000000000200(slab) raw: 0100000000000200 ffffea0000391680 0000000f0000000f ffff888007c418c0 raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888021991e80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc ffff888021991f00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff888021991f80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff888021992000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888021992080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== BUG: unable to handle page fault for address: ffffde200ec911b0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 7c2a067 P4D 7c2a067 PUD 0 Oops: 0000 [#1] SMP KASAN NOPTI CPU: 1 PID: 373 Comm: syz-fuzzer Tainted: G B W 5.10.45 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 RIP: 0010:percpu_ref_switch_to_atomic_rcu+0xcb/0x3a0 lib/percpu-refcount.c:175 Code: c0 56 a5 84 48 89 fa 48 c1 ea 03 80 3c 2a 00 0f 85 67 02 00 00 4a 8b 04 ed c0 56 a5 84 4c 01 e0 48 89 c2 49 89 c5 48 c1 ea 03 <80> 3c 2a 00 0f 85 52 02 00 00 49 03 5d 00 e8 c2 25 52 ff 44 89 ff RSP: 0018:ffff88806cf09e30 EFLAGS: 00010212 RAX: ffff110076488d80 RBX: 0000000000000000 RCX: ffffffff81ed6637 RDX: 1fffe2200ec911b0 RSI: ffffffff81ed65ba RDI: ffffffff84a556c0 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8544f08f R10: 0000000000000000 R11: 0000000000000001 R12: ffff888009688d80 R13: ffff110076488d80 R14: ffff888021991fa0 R15: 0000000000000000 FS: 000000c000030090(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffde200ec911b0 CR3: 000000000eb14000 CR4: 0000000000350ee0 Call Trace: rcu_do_batch kernel/rcu/tree.c:2484 [inline] rcu_core+0x52d/0x1640 kernel/rcu/tree.c:2719 __do_softirq+0x1b8/0x85f kernel/softirq.c:298 asm_call_irq_on_stack+0x12/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0x80/0xa0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x110/0x1a0 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x43/0xa0 arch/x86/kernel/apic/apic.c:1095 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:644 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:49 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:__schedule+0x1bc/0x1e70 kernel/sched/core.c:4425 Code: c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 8a 16 00 00 83 3d 71 ec 80 01 02 0f 84 a2 13 00 00 0f 1f 44 00 00 9c 58 f6 c4 02 0f 85 24 0d 00 00 8b bd 44 ff ff ff e8 0f a4 69 fd 4c RSP: 0018:ffff888021a87bb0 EFLAGS: 00000293 RAX: 0000000000000293 RBX: 0000000000000000 RCX: 1ffffffff0a89e40 RDX: 0000000000000000 RSI: ffffffff83c4231b RDI: ffffffff84df63e0 RBP: ffff888021a87c80 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88806cf33180 R13: ffff8880161b1940 R14: 0000000000033180 R15: 0000000000000000 schedule+0xcb/0x270 kernel/sched/core.c:4603 freezable_schedule include/linux/freezer.h:172 [inline] do_nanosleep+0x1b1/0x670 kernel/time/hrtimer.c:1896 hrtimer_nanosleep+0x25c/0x680 kernel/time/hrtimer.c:1949 __do_sys_nanosleep kernel/time/hrtimer.c:1983 [inline] __se_sys_nanosleep kernel/time/hrtimer.c:1970 [inline] __x64_sys_nanosleep+0x1dc/0x260 kernel/time/hrtimer.c:1970 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x465f2d Code: 8b 44 24 20 b9 40 42 0f 00 f7 f1 48 89 04 24 b8 e8 03 00 00 f7 e2 48 89 44 24 08 48 89 e7 be 00 00 00 00 b8 23 00 00 00 0f 05 <48> 8b 6c 24 10 48 83 c4 18 c3 cc cc cc cc cc cc cc cc cc b8 ba 00 RSP: 002b:000000c00003ff18 EFLAGS: 00000212 ORIG_RAX: 0000000000000023 RAX: ffffffffffffffda RBX: 0000000000000014 RCX: 0000000000465f2d RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000c00003ff18 RBP: 000000c00003ff28 R08: 000000000001e8f5 R09: 00007ffe42bb4090 R10: 00000000000b5ba6 R11: 0000000000000212 R12: 0000000000438880 R13: 0000000000000000 R14: 0000000000b5838c R15: 0000000000000000 Modules linked in: CR2: ffffde200ec911b0 ---[ end trace 266a8ec2f43711e2 ]--- RIP: 0010:percpu_ref_switch_to_atomic_rcu+0xcb/0x3a0 lib/percpu-refcount.c:175 Code: c0 56 a5 84 48 89 fa 48 c1 ea 03 80 3c 2a 00 0f 85 67 02 00 00 4a 8b 04 ed c0 56 a5 84 4c 01 e0 48 89 c2 49 89 c5 48 c1 ea 03 <80> 3c 2a 00 0f 85 52 02 00 00 49 03 5d 00 e8 c2 25 52 ff 44 89 ff RSP: 0018:ffff88806cf09e30 EFLAGS: 00010212 RAX: ffff110076488d80 RBX: 0000000000000000 RCX: ffffffff81ed6637 RDX: 1fffe2200ec911b0 RSI: ffffffff81ed65ba RDI: ffffffff84a556c0 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8544f08f R10: 0000000000000000 R11: 0000000000000001 R12: ffff888009688d80 R13: ffff110076488d80 R14: ffff888021991fa0 R15: 0000000000000000 FS: 000000c000030090(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffde200ec911b0 CR3: 000000000eb14000 CR4: 0000000000350ee0