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BUG: KASAN: slab-use-[  233.654983][ T8848] BUG: KASAN: slab-use-after-free in clear_tfile_check_list+0x114/0x380 fs/eventpoll.c:2443
Read of size 8 at addr ffff88802f7ec108 by task syz.0.1038/8848

CPU: 1 UID: 0 PID: 8848 Comm: syz.0.1038 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 clear_tfile_check_list+0x114/0x380 fs/eventpoll.c:2443
 do_epoll_ctl_file+0x8fd/0xed0 fs/eventpoll.c:-1
 do_epoll_ctl fs/eventpoll.c:2698 [inline]
 __do_sys_epoll_ctl fs/eventpoll.c:2715 [inline]
 __se_sys_epoll_ctl+0x14e/0x210 fs/eventpoll.c:2706
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdaeeacce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdaec8b9028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: ffffffffffffffda RBX: 00007fdaeed46270 RCX: 00007fdaeeacce59
RDX: 0000000000000005 RSI: 0000000000000001 RDI: 0000000000000008
RBP: 00007fdaeeb62d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdaeed46308 R14: 00007fdaeed46270 R15: 00007fffadfe02d8
 </TASK>

Allocated by task 8846:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4583 [inline]
 slab_alloc_node mm/slub.c:4912 [inline]
 kmem_cache_alloc_noprof+0x33b/0x680 mm/slub.c:4919
 ep_attach_file fs/eventpoll.c:1751 [inline]
 ep_register_epitem fs/eventpoll.c:1833 [inline]
 ep_insert+0x512/0x1820 fs/eventpoll.c:1876
 do_epoll_ctl_file+0x8bb/0xed0 fs/eventpoll.c:2651
 do_epoll_ctl fs/eventpoll.c:2698 [inline]
 __do_sys_epoll_ctl fs/eventpoll.c:2715 [inline]
 __se_sys_epoll_ctl+0x14e/0x210 fs/eventpoll.c:2706
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 8842:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2700 [inline]
 slab_free mm/slub.c:6284 [inline]
 kmem_cache_free+0x187/0x6c0 mm/slub.c:6411
 eventpoll_release_file+0xc2/0x240 fs/eventpoll.c:1386
 eventpoll_release include/linux/eventpoll.h:61 [inline]
 __fput+0x83c/0xa70 fs/file_table.c:501
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 get_signal+0x11eb/0x1330 kernel/signal.c:2810
 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0xa9/0x680 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802f7ec100
 which belongs to the cache ep_head of size 16
The buggy address is located 8 bytes inside of
 freed 16-byte region [ffff88802f7ec100, ffff88802f7ec110)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802f7ec180 pfn:0x2f7ec
memcg:ffff8880596ad801
flags: 0x80000000000200(workingset|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000200 ffff88814041adc0 ffffea0000fda7d0 ffffea0000fbffd0
raw: ffff88802f7ec180 0000000800800016 00000000f5000000 ffff8880596ad801
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4986, tgid 4986 (udevd), ts 40833053512, free_ts 40782535205
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x265c/0x26e0 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5300
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5e0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7216
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4665
 alloc_from_pcs mm/slub.c:4763 [inline]
 slab_alloc_node mm/slub.c:4897 [inline]
 kmem_cache_alloc_noprof+0x433/0x680 mm/slub.c:4919
 ep_attach_file fs/eventpoll.c:1751 [inline]
 ep_register_epitem fs/eventpoll.c:1833 [inline]
 ep_insert+0x512/0x1820 fs/eventpoll.c:1876
 do_epoll_ctl_file+0x8bb/0xed0 fs/eventpoll.c:2651
 do_epoll_ctl fs/eventpoll.c:2698 [inline]
 __do_sys_epoll_ctl fs/eventpoll.c:2715 [inline]
 __se_sys_epoll_ctl+0x14e/0x210 fs/eventpoll.c:2706
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4986 tgid 4986 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x10af/0x1190 mm/page_alloc.c:2950
 __slab_free+0x252/0x2a0 mm/slub.c:5646
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4583 [inline]
 slab_alloc_node mm/slub.c:4912 [inline]
 kmem_cache_alloc_noprof+0x33b/0x680 mm/slub.c:4919
 anon_vma_chain_alloc mm/rmap.c:142 [inline]
 anon_vma_clone+0x3e5/0x9f0 mm/rmap.c:342
 anon_vma_fork+0x16a/0x570 mm/rmap.c:404
 dup_mmap+0x997/0x1d70 mm/mmap.c:1803
 dup_mm kernel/fork.c:1542 [inline]
 copy_mm+0x11a/0x480 kernel/fork.c:1594
 copy_process+0x1e30/0x43d0 kernel/fork.c:2291
 kernel_clone+0x2d7/0x940 kernel/fork.c:2749
 __do_sys_clone kernel/fork.c:2890 [inline]
 __se_sys_clone kernel/fork.c:2874 [inline]
 __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2874
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802f7ec000: fa fb fc fc fa fb fc fc fc fc fc fc fc fc fc fc
 ffff88802f7ec080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802f7ec100: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
                      ^
 ffff88802f7ec180: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
 ffff88802f7ec200: fa fb fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
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