================================================================== BUG: KASAN: use-after-free in io_poll_check_events io_uring/poll.c:244 [inline] BUG: KASAN: use-after-free in io_poll_task_func+0xf77/0x1220 io_uring/poll.c:327 Read of size 4 at addr ffff888085e21d6c by task kworker/1:8/5241 CPU: 1 PID: 5241 Comm: kworker/1:8 Not tainted 6.2.0-rc3-next-20230112-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: events io_fallback_req_func Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:306 [inline] print_report+0x15e/0x45d mm/kasan/report.c:417 kasan_report+0xc0/0xf0 mm/kasan/report.c:517 io_poll_check_events io_uring/poll.c:244 [inline] io_poll_task_func+0xf77/0x1220 io_uring/poll.c:327 io_fallback_req_func+0xfd/0x204 io_uring/io_uring.c:252 process_one_work+0x9bf/0x1750 kernel/workqueue.c:2293 worker_thread+0x669/0x1090 kernel/workqueue.c:2440 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 Allocated by task 22336: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 __kasan_slab_alloc+0x7f/0x90 mm/kasan/common.c:325 kasan_slab_alloc include/linux/kasan.h:186 [inline] slab_post_alloc_hook mm/slab.h:769 [inline] slab_alloc_node mm/slub.c:3452 [inline] kmem_cache_alloc_node+0x183/0x350 mm/slub.c:3497 alloc_task_struct_node kernel/fork.c:171 [inline] dup_task_struct kernel/fork.c:979 [inline] copy_process+0x3aa/0x7740 kernel/fork.c:2103 kernel_clone+0xeb/0x9a0 kernel/fork.c:2687 __do_sys_clone+0xba/0x100 kernel/fork.c:2828 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 5241: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x40 mm/kasan/generic.c:518 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:162 [inline] slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1807 slab_free mm/slub.c:3787 [inline] kmem_cache_free+0xec/0x4e0 mm/slub.c:3809 put_task_struct_many include/linux/sched/task.h:125 [inline] __io_put_task+0x155/0x1e0 io_uring/io_uring.c:725 io_put_task io_uring/io_uring.h:328 [inline] __io_req_complete_post+0x7ac/0xcd0 io_uring/io_uring.c:978 io_req_complete_post+0xf1/0x1a0 io_uring/io_uring.c:992 io_req_task_complete+0x189/0x260 io_uring/io_uring.c:1623 io_poll_task_func+0xa95/0x1220 io_uring/poll.c:347 io_fallback_req_func+0xfd/0x204 io_uring/io_uring.c:252 process_one_work+0x9bf/0x1750 kernel/workqueue.c:2293 worker_thread+0x669/0x1090 kernel/workqueue.c:2440 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 Last potentially related work creation: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:488 __call_rcu_common.constprop.0+0x99/0x780 kernel/rcu/tree.c:2622 put_task_struct_rcu_user+0x83/0xc0 kernel/exit.c:231 context_switch kernel/sched/core.c:5304 [inline] __schedule+0x25d8/0x5a70 kernel/sched/core.c:6619 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6788 preempt_schedule_thunk+0x1a/0x20 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irq+0x40/0x50 kernel/locking/spinlock.c:202 spin_unlock_irq include/linux/spinlock.h:400 [inline] do_group_exit+0x1c5/0x2a0 kernel/exit.c:1009 __do_sys_exit_group kernel/exit.c:1023 [inline] __se_sys_exit_group kernel/exit.c:1021 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1021 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Second to last potentially related work creation: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:488 __call_rcu_common.constprop.0+0x99/0x780 kernel/rcu/tree.c:2622 put_task_struct_rcu_user+0x83/0xc0 kernel/exit.c:231 release_task+0xcc8/0x1870 kernel/exit.c:281 wait_task_zombie kernel/exit.c:1198 [inline] wait_consider_task+0x306d/0x3ce0 kernel/exit.c:1425 do_wait_thread kernel/exit.c:1488 [inline] do_wait+0x7cd/0xd90 kernel/exit.c:1605 kernel_wait4+0x150/0x260 kernel/exit.c:1768 __do_sys_wait4+0x13f/0x150 kernel/exit.c:1796 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff888085e21d40 which belongs to the cache task_struct of size 7232 The buggy address is located 44 bytes inside of 7232-byte region [ffff888085e21d40, ffff888085e23980) The buggy address belongs to the physical page: page:ffffea0002178800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x85e20 head:ffffea0002178800 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff88802a511441 anon flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffff8880125ec500 0000000000000000 0000000000000001 raw: 0000000000000000 0000000000040004 00000001ffffffff ffff88802a511441 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5140, tgid 5140 (syz-executor.4), ts 940002279505, free_ts 939439685406 prep_new_page mm/page_alloc.c:2549 [inline] get_page_from_freelist+0x11bb/0x2d50 mm/page_alloc.c:4324 __alloc_pages+0x1cb/0x5c0 mm/page_alloc.c:5590 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2281 alloc_slab_page mm/slub.c:1851 [inline] allocate_slab+0x25f/0x350 mm/slub.c:1998 new_slab mm/slub.c:2051 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3193 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3292 __slab_alloc_node mm/slub.c:3345 [inline] slab_alloc_node mm/slub.c:3442 [inline] kmem_cache_alloc_node+0x136/0x350 mm/slub.c:3497 alloc_task_struct_node kernel/fork.c:171 [inline] dup_task_struct kernel/fork.c:979 [inline] copy_process+0x3aa/0x7740 kernel/fork.c:2103 kernel_clone+0xeb/0x9a0 kernel/fork.c:2687 __do_sys_clone+0xba/0x100 kernel/fork.c:2828 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1451 [inline] free_pcp_prepare+0x4d0/0x910 mm/page_alloc.c:1501 free_unref_page_prepare mm/page_alloc.c:3387 [inline] free_unref_page+0x1d/0x490 mm/page_alloc.c:3482 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2637 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x192/0x220 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x63/0x90 mm/kasan/common.c:302 kasan_slab_alloc include/linux/kasan.h:186 [inline] slab_post_alloc_hook mm/slab.h:769 [inline] slab_alloc_node mm/slub.c:3452 [inline] slab_alloc mm/slub.c:3460 [inline] __kmem_cache_alloc_lru mm/slub.c:3467 [inline] kmem_cache_alloc+0x175/0x320 mm/slub.c:3476 getname_flags.part.0+0x50/0x4f0 fs/namei.c:140 getname_flags include/linux/audit.h:320 [inline] getname+0x92/0xd0 fs/namei.c:219 do_sys_openat2+0xf5/0x4c0 fs/open.c:1305 do_sys_open fs/open.c:1327 [inline] __do_sys_openat fs/open.c:1343 [inline] __se_sys_openat fs/open.c:1338 [inline] __x64_sys_openat+0x143/0x1f0 fs/open.c:1338 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffff888085e21c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888085e21c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888085e21d00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ^ ffff888085e21d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888085e21e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================