================================================================== BUG: KASAN: use-after-free in io_kill_linked_timeout+0x7fa/0x960 fs/io_uring.c:1932 Read of size 4 at addr ffff88810d76c918 by task syz-executor.4/530 CPU: 1 PID: 530 Comm: syz-executor.4 Not tainted 5.10.100-syzkaller-00843-g86e6176a4240 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118 print_address_description+0x8d/0x3d0 mm/kasan/report.c:233 __kasan_report+0x142/0x220 mm/kasan/report.c:419 kasan_report+0x51/0x70 mm/kasan/report.c:436 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 io_kill_linked_timeout+0x7fa/0x960 fs/io_uring.c:1932 __io_req_find_next fs/io_uring.c:2011 [inline] io_req_find_next fs/io_uring.c:2029 [inline] io_queue_next fs/io_uring.c:2128 [inline] io_free_req fs/io_uring.c:2136 [inline] io_put_req_deferred_cb+0xb2/0x520 fs/io_uring.c:2233 task_work_run+0x147/0x1b0 kernel/task_work.c:154 get_signal+0x167f/0x1f70 kernel/signal.c:2584 arch_do_signal+0x8d/0x620 arch/x86/kernel/signal.c:805 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0xaa/0xe0 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x24/0x40 kernel/entry/common.c:266 do_syscall_64+0x3d/0x70 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f6c11781059 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 RSP: 002b:00007f6c108b5168 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: 0000000000000200 RBX: 00007f6c11894100 RCX: 00007f6c11781059 RDX: 0000000000000000 RSI: 0000000000003ed9 RDI: 0000000000000003 RBP: 00007f6c117db08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc4cdc406f R14: 00007f6c108b5300 R15: 0000000000022000 Allocated by task 530: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:428 [inline] __kasan_slab_alloc+0xb2/0xe0 mm/kasan/common.c:461 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:583 [inline] kmem_cache_alloc_bulk+0x2d5/0x3f0 mm/slub.c:3412 io_alloc_req fs/io_uring.c:1857 [inline] io_submit_sqes+0x6bf/0x2da0 fs/io_uring.c:6697 __do_sys_io_uring_enter fs/io_uring.c:9113 [inline] __se_sys_io_uring_enter+0x322/0x12b0 fs/io_uring.c:9055 __x64_sys_io_uring_enter+0xe5/0x100 fs/io_uring.c:9055 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 530: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:46 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:357 ____kasan_slab_free+0x133/0x170 mm/kasan/common.c:360 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:368 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:1602 [inline] slab_free_freelist_hook+0xcc/0x1a0 mm/slub.c:1628 slab_free mm/slub.c:3210 [inline] kmem_cache_free+0xb5/0x1f0 mm/slub.c:3226 __io_free_req+0x20e/0x380 fs/io_uring.c:1912 io_free_req fs/io_uring.c:2137 [inline] io_put_req_deferred_cb+0x64/0x520 fs/io_uring.c:2233 task_work_run+0x147/0x1b0 kernel/task_work.c:154 get_signal+0x167f/0x1f70 kernel/signal.c:2584 arch_do_signal+0x8d/0x620 arch/x86/kernel/signal.c:805 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0xaa/0xe0 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x24/0x40 kernel/entry/common.c:266 do_syscall_64+0x3d/0x70 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Last potentially related work creation: kasan_save_stack+0x36/0x60 mm/kasan/common.c:38 kasan_record_aux_stack+0xd3/0xf0 mm/kasan/generic.c:345 task_work_add+0xa7/0x320 kernel/task_work.c:39 io_req_task_work_add fs/io_uring.c:2052 [inline] io_free_req_deferred fs/io_uring.c:2241 [inline] io_put_req_deferred+0x12a/0x240 fs/io_uring.c:2254 io_link_timeout_fn+0x4c8/0x600 fs/io_uring.c:6279 __run_hrtimer+0x199/0x6a0 kernel/time/hrtimer.c:1583 __hrtimer_run_queues kernel/time/hrtimer.c:1647 [inline] hrtimer_interrupt+0x639/0x1380 kernel/time/hrtimer.c:1709 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1084 [inline] __sysvec_apic_timer_interrupt+0xf9/0x3c0 arch/x86/kernel/apic/apic.c:1101 asm_call_irq_on_stack+0xf/0x20 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline] run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline] sysvec_apic_timer_interrupt+0x85/0xe0 arch/x86/kernel/apic/apic.c:1095 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635 The buggy address belongs to the object at ffff88810d76c8c0 which belongs to the cache io_kiocb of size 216 The buggy address is located 88 bytes inside of 216-byte region [ffff88810d76c8c0, ffff88810d76c998) The buggy address belongs to the page: page:ffffea000435db00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10d76c flags: 0x8000000000000200(slab) raw: 8000000000000200 dead000000000100 dead000000000122 ffff888102bf0000 raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 516, ts 3410864688867, free_ts 3410855950353 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2385 [inline] prep_new_page mm/page_alloc.c:2391 [inline] get_page_from_freelist+0xa74/0xa90 mm/page_alloc.c:4063 __alloc_pages_nodemask+0x3c8/0x820 mm/page_alloc.c:5107 alloc_slab_page mm/slub.c:1813 [inline] allocate_slab+0x6b/0x350 mm/slub.c:1815 new_slab mm/slub.c:1876 [inline] new_slab_objects mm/slub.c:2635 [inline] ___slab_alloc+0x143/0x2f0 mm/slub.c:2798 kmem_cache_alloc_bulk+0x167/0x3f0 mm/slub.c:3391 io_alloc_req fs/io_uring.c:1857 [inline] io_submit_sqes+0x6bf/0x2da0 fs/io_uring.c:6697 __do_sys_io_uring_enter fs/io_uring.c:9113 [inline] __se_sys_io_uring_enter+0x322/0x12b0 fs/io_uring.c:9055 __x64_sys_io_uring_enter+0xe5/0x100 fs/io_uring.c:9055 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 page last free stack trace: reset_page_owner include/linux/page_owner.h:28 [inline] free_pages_prepare mm/page_alloc.c:1331 [inline] free_pcp_prepare+0x18f/0x1c0 mm/page_alloc.c:1405 free_unref_page_prepare mm/page_alloc.c:3291 [inline] free_unref_page mm/page_alloc.c:3341 [inline] free_the_page mm/page_alloc.c:5166 [inline] __free_pages+0x2e3/0x4a0 mm/page_alloc.c:5174 __vunmap+0x856/0x980 mm/vmalloc.c:2275 free_work+0x66/0x90 mm/vmalloc.c:68 process_one_work+0x6b4/0xfb0 kernel/workqueue.c:2296 worker_thread+0xb15/0x1600 kernel/workqueue.c:2442 kthread+0x371/0x390 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Memory state around the buggy address: ffff88810d76c800: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff88810d76c880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff88810d76c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810d76c980: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88810d76ca00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 530 at lib/refcount.c:28 refcount_warn_saturate+0x165/0x1b0 lib/refcount.c:28 Modules linked in: CPU: 1 PID: 530 Comm: syz-executor.4 Tainted: G B 5.10.100-syzkaller-00843-g86e6176a4240 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:refcount_warn_saturate+0x165/0x1b0 lib/refcount.c:28 Code: c7 20 b8 49 85 31 c0 e8 a9 a8 ea fe 0f 0b eb 83 e8 70 cd 17 ff c6 05 6e 0a 68 04 01 48 c7 c7 80 b8 49 85 31 c0 e8 8b a8 ea fe <0f> 0b e9 62 ff ff ff e8 4f cd 17 ff c6 05 4e 0a 68 04 01 48 c7 c7 RSP: 0018:ffffc900034d7a70 EFLAGS: 00010246 RAX: 1fe4ceb7a266e600 RBX: 0000000000000003 RCX: 1ffff9200069af08 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: ffffc900034d7a80 R08: ffffffff815454a8 R09: ffffed103ee2a5d8 R10: ffffed103ee2a5d8 R11: 0000000000000000 R12: ffff88810d76c930 R13: ffff88810d76ccd8 R14: 0000000000000003 R15: 00000000ffffffff FS: 00007f6c108b5700(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe7b6637718 CR3: 000000010e125000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_sub_and_test include/linux/refcount.h:283 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] io_put_req fs/io_uring.c:2225 [inline] io_kill_linked_timeout+0x3f4/0x960 fs/io_uring.c:1949 __io_req_find_next fs/io_uring.c:2011 [inline] io_req_find_next fs/io_uring.c:2029 [inline] io_queue_next fs/io_uring.c:2128 [inline] io_free_req fs/io_uring.c:2136 [inline] io_put_req_deferred_cb+0xb2/0x520 fs/io_uring.c:2233 task_work_run+0x147/0x1b0 kernel/task_work.c:154 get_signal+0x167f/0x1f70 kernel/signal.c:2584 arch_do_signal+0x8d/0x620 arch/x86/kernel/signal.c:805 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0xaa/0xe0 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x24/0x40 kernel/entry/common.c:266 do_syscall_64+0x3d/0x70 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f6c11781059 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 RSP: 002b:00007f6c108b5168 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: 0000000000000200 RBX: 00007f6c11894100 RCX: 00007f6c11781059 RDX: 0000000000000000 RSI: 0000000000003ed9 RDI: 0000000000000003 RBP: 00007f6c117db08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc4cdc406f R14: 00007f6c108b5300 R15: 0000000000022000 ---[ end trace 40ccdb555b789ae9 ]---