BUG: KASAN: use-after-free in io_queue_link_head+0x4ce/0x5c0 fs/io_uring.c:2542
Read of size 8 at addr ffff8881e2d37550 by task syz-executor.2/29152

CPU: 0 PID: 29152 Comm: syz-executor.2 Not tainted 5.4.161-syzkaller-00055-g2159354389cf #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+0x18e/0x1de lib/dump_stack.c:118
 print_address_description+0x9b/0x650 mm/kasan/report.c:384
 __kasan_report+0x182/0x260 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 io_queue_link_head+0x4ce/0x5c0 fs/io_uring.c:2542
 io_ring_submit fs/io_uring.c:2971 [inline]
 __do_sys_io_uring_enter fs/io_uring.c:3853 [inline]
 __se_sys_io_uring_enter+0xafd/0x1d40 fs/io_uring.c:3814
 do_syscall_64+0xcb/0x1e0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fbcfa03c059
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:00007fbcf91b2168 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007fbcfa14ef60 RCX: 00007fbcfa03c059
RDX: 0000000000000000 RSI: 00000000000002ff RDI: 0000000000000003
RBP: 00007fbcf91b21d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd1f46ef2f R14: 00007fbcf91b2300 R15: 0000000000022000

Allocated by task 29152:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 __kasan_kmalloc+0x137/0x1e0 mm/kasan/common.c:529
 slab_post_alloc_hook mm/slab.h:584 [inline]
 kmem_cache_alloc_bulk+0x18e/0x290 mm/slub.c:3291
 io_get_req+0x17a/0x590 fs/io_uring.c:652
 io_submit_sqe+0x83/0xe80 fs/io_uring.c:2579
 io_ring_submit fs/io_uring.c:2967 [inline]
 __do_sys_io_uring_enter fs/io_uring.c:3853 [inline]
 __se_sys_io_uring_enter+0x7ee/0x1d40 fs/io_uring.c:3814
 do_syscall_64+0xcb/0x1e0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 29152:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 kasan_set_free_info mm/kasan/common.c:345 [inline]
 __kasan_slab_free+0x18a/0x240 mm/kasan/common.c:487
 slab_free_hook mm/slub.c:1455 [inline]
 slab_free_freelist_hook+0x80/0x150 mm/slub.c:1494
 slab_free mm/slub.c:3080 [inline]
 kmem_cache_free+0xc5/0x610 mm/slub.c:3096
 io_queue_link_head+0x2c5/0x5c0 fs/io_uring.c:2540
 io_ring_submit fs/io_uring.c:2971 [inline]
 __do_sys_io_uring_enter fs/io_uring.c:3853 [inline]
 __se_sys_io_uring_enter+0xafd/0x1d40 fs/io_uring.c:3814
 do_syscall_64+0xcb/0x1e0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8881e2d37500
 which belongs to the cache io_kiocb of size 264
The buggy address is located 80 bytes inside of
 264-byte region [ffff8881e2d37500, ffff8881e2d37608)
The buggy address belongs to the page:
page:ffffea00078b4d80 refcount:1 mapcount:0 mapping:ffff8881f0ef0f00 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 ffffea0007bdc300 0000000400000004 ffff8881f0ef0f00
raw: 0000000000000000 0000000080150015 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x19a/0x380 mm/page_alloc.c:2171
 get_page_from_freelist+0x550/0x8b0 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x2d6/0x740 mm/page_alloc.c:4855
 alloc_slab_page+0x39/0x3e0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x97/0x460 mm/slub.c:1749
 new_slab_objects mm/slub.c:2506 [inline]
 ___slab_alloc+0x330/0x4c0 mm/slub.c:2667
 kmem_cache_alloc_bulk+0xc7/0x290 mm/slub.c:3265
 io_get_req+0x17a/0x590 fs/io_uring.c:652
 io_submit_sqe+0x83/0xe80 fs/io_uring.c:2579
 io_ring_submit fs/io_uring.c:2967 [inline]
 __do_sys_io_uring_enter fs/io_uring.c:3853 [inline]
 __se_sys_io_uring_enter+0x7ee/0x1d40 fs/io_uring.c:3814
 do_syscall_64+0xcb/0x1e0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 free_pcp_prepare+0x1a9/0x270 mm/page_alloc.c:1233
 free_unref_page_prepare mm/page_alloc.c:3085 [inline]
 free_unref_page_list+0xc2/0x5a0 mm/page_alloc.c:3154
 release_pages+0x92a/0x950 mm/swap.c:842
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:184 [inline]
 tlb_flush_mmu+0x77f/0x910 mm/mmu_gather.c:191
 tlb_finish_mmu+0xcb/0x200 mm/mmu_gather.c:272
 exit_mmap+0x2a6/0x4f0 mm/mmap.c:3176
 __mmput+0x34/0x240 kernel/fork.c:1090
 exit_mm kernel/exit.c:489 [inline]
 do_exit+0xb6a/0x2aa0 kernel/exit.c:799
 do_group_exit+0x15c/0x2c0 kernel/exit.c:910
 get_signal+0x151f/0x1e10 kernel/signal.c:2735
 do_signal+0x3b/0x580 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop arch/x86/entry/common.c:159 [inline]
 prepare_exit_to_usermode+0x207/0x310 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Memory state around the buggy address:
 ffff8881e2d37400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881e2d37480: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881e2d37500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff8881e2d37580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e2d37600: fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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