================================================================== BUG: KASAN: slab-use-after-free in sysfs_remove_file_ns+0x3d/0x70 fs/sysfs/file.c:510 Read of size 8 at addr ffff8880338d8a30 by task syz.6.5785/26982 CPU: 1 UID: 0 PID: 26982 Comm: syz.6.5785 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 sysfs_remove_file_ns+0x3d/0x70 fs/sysfs/file.c:510 remove_bind_files drivers/base/bus.c:605 [inline] bus_remove_driver+0x198/0x2f0 drivers/base/bus.c:743 comedi_device_detach_locked+0x178/0x750 drivers/comedi/drivers.c:207 do_devconfig_ioctl drivers/comedi/comedi_fops.c:848 [inline] comedi_unlocked_ioctl+0xcde/0x1020 drivers/comedi/comedi_fops.c:2178 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3fef38eba9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3ff01a0038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3fef5d5fa0 RCX: 00007f3fef38eba9 RDX: 0000000000000000 RSI: 0000000040946400 RDI: 0000000000000008 RBP: 00007f3fef411e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3fef5d6038 R14: 00007f3fef5d5fa0 R15: 00007ffc2c3780f8 Allocated by task 26210: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5584 [inline] __kmalloc_noprof+0x411/0x7f0 mm/slub.c:5596 kmalloc_noprof include/linux/slab.h:961 [inline] io_cache_alloc_new+0x40/0x100 io_uring/alloc_cache.c:40 io_cache_alloc io_uring/alloc_cache.h:59 [inline] io_uring_alloc_async_data io_uring/io_uring.h:323 [inline] io_rw_alloc_async io_uring/rw.c:202 [inline] __io_prep_rw+0x23f/0xe20 io_uring/rw.c:261 io_prep_rw io_uring/rw.c:322 [inline] io_prep_rwv+0x91/0x3e0 io_uring/rw.c:344 io_init_req io_uring/io_uring.c:2250 [inline] io_submit_sqe io_uring/io_uring.c:2297 [inline] io_submit_sqes+0x935/0x1e60 io_uring/io_uring.c:2449 __do_sys_io_uring_enter io_uring/io_uring.c:3516 [inline] __se_sys_io_uring_enter+0x2df/0x2b20 io_uring/io_uring.c:3455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 26210: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2505 [inline] slab_free mm/slub.c:6537 [inline] kfree+0x19c/0x6e0 mm/slub.c:6745 io_clean_op+0x298/0x330 io_uring/io_uring.c:420 io_free_batch_list io_uring/io_uring.c:1533 [inline] __io_submit_flush_completions+0xd28/0xf50 io_uring/io_uring.c:1571 io_submit_flush_completions io_uring/io_uring.h:220 [inline] io_submit_state_end io_uring/io_uring.c:2350 [inline] io_submit_sqes+0x193d/0x1e60 io_uring/io_uring.c:2464 __do_sys_io_uring_enter io_uring/io_uring.c:3516 [inline] __se_sys_io_uring_enter+0x2df/0x2b20 io_uring/io_uring.c:3455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880338d8a00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 48 bytes inside of freed 256-byte region [ffff8880338d8a00, ffff8880338d8b00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880338d8a00 pfn:0x338d8 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801a841b40 ffffea0000ca3e90 ffffea00009d8190 raw: ffff8880338d8a00 000000000010000e 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801a841b40 ffffea0000ca3e90 ffffea00009d8190 head: ffff8880338d8a00 000000000010000e 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000ce3601 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11336, tgid 11335 (syz.4.1542), ts 540055779295, free_ts 540013758154 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3869 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5159 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3021 [inline] allocate_slab+0x96/0x3a0 mm/slub.c:3194 new_slab mm/slub.c:3248 [inline] ___slab_alloc+0xe94/0x1920 mm/slub.c:4621 __slab_alloc+0x65/0x100 mm/slub.c:4727 __slab_alloc_node mm/slub.c:4803 [inline] slab_alloc_node mm/slub.c:5214 [inline] __do_kmalloc_node mm/slub.c:5583 [inline] __kmalloc_noprof+0x471/0x7f0 mm/slub.c:5596 kmalloc_noprof include/linux/slab.h:961 [inline] io_cache_alloc_new+0x40/0x100 io_uring/alloc_cache.c:40 io_cache_alloc io_uring/alloc_cache.h:59 [inline] io_uring_alloc_async_data io_uring/io_uring.h:323 [inline] io_rw_alloc_async io_uring/rw.c:202 [inline] __io_prep_rw+0x23f/0xe20 io_uring/rw.c:261 io_prep_rw io_uring/rw.c:322 [inline] io_prep_rwv+0x91/0x3e0 io_uring/rw.c:344 io_init_req io_uring/io_uring.c:2250 [inline] io_submit_sqe io_uring/io_uring.c:2297 [inline] io_submit_sqes+0x935/0x1e60 io_uring/io_uring.c:2449 __do_sys_io_uring_enter io_uring/io_uring.c:3516 [inline] __se_sys_io_uring_enter+0x2df/0x2b20 io_uring/io_uring.c:3455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 6083 tgid 6083 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906 mm_free_pgd kernel/fork.c:556 [inline] __mmdrop+0xb5/0x570 kernel/fork.c:698 mmdrop include/linux/sched/mm.h:55 [inline] io_ring_ctx_free+0x468/0x4e0 io_uring/io_uring.c:2863 io_ring_exit_work+0x8c4/0x930 io_uring/io_uring.c:3088 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff8880338d8900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880338d8980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880338d8a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880338d8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880338d8b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================