================================================================== BUG: KASAN: slab-use-after-free in io_req_local_work_add io_uring/io_uring.c:1272 [inline] BUG: KASAN: slab-use-after-free in __io_req_task_work_add+0x589/0x950 io_uring/io_uring.c:1340 Read of size 4 at addr ffff888075c7e7c4 by task iou-wrk-6406/6408 CPU: 0 UID: 0 PID: 6408 Comm: iou-wrk-6406 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 io_req_local_work_add io_uring/io_uring.c:1272 [inline] __io_req_task_work_add+0x589/0x950 io_uring/io_uring.c:1340 io_msg_remote_post io_uring/msg_ring.c:103 [inline] io_msg_data_remote io_uring/msg_ring.c:133 [inline] __io_msg_ring_data+0x7f6/0xa80 io_uring/msg_ring.c:151 io_msg_ring_data io_uring/msg_ring.c:173 [inline] io_msg_ring+0x134/0xa00 io_uring/msg_ring.c:314 __io_issue_sqe+0x181/0x4b0 io_uring/io_uring.c:1826 io_issue_sqe+0x165/0xfe0 io_uring/io_uring.c:1849 io_wq_submit_work+0x6e9/0xb90 io_uring/io_uring.c:1961 io_worker_handle_work+0x7cd/0x1180 io_uring/io-wq.c:650 io_wq_worker+0x42f/0xeb0 io_uring/io-wq.c:704 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 6406: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4945 [inline] slab_alloc_node mm/slub.c:5244 [inline] kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5251 io_msg_get_kiocb io_uring/msg_ring.c:117 [inline] io_msg_data_remote io_uring/msg_ring.c:126 [inline] __io_msg_ring_data+0x47b/0xa80 io_uring/msg_ring.c:151 io_msg_ring_data io_uring/msg_ring.c:173 [inline] io_msg_ring+0x134/0xa00 io_uring/msg_ring.c:314 __io_issue_sqe+0x181/0x4b0 io_uring/io_uring.c:1826 io_issue_sqe+0x165/0xfe0 io_uring/io_uring.c:1849 io_queue_sqe io_uring/io_uring.c:2076 [inline] io_submit_sqe io_uring/io_uring.c:2336 [inline] io_submit_sqes+0xa54/0x1e60 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 6406: 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_mempool_poison_object+0xad/0x130 mm/kasan/common.c:545 kasan_mempool_poison_object include/linux/kasan.h:362 [inline] io_alloc_cache_put io_uring/alloc_cache.h:23 [inline] io_msg_tw_complete+0x12c/0x4f0 io_uring/msg_ring.c:80 __io_run_local_work_loop io_uring/io_uring.c:1383 [inline] __io_run_local_work+0x353/0x810 io_uring/io_uring.c:1416 io_run_local_work_locked io_uring/io_uring.c:1438 [inline] __do_sys_io_uring_enter io_uring/io_uring.c:3529 [inline] __se_sys_io_uring_enter+0x1725/0x2b20 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 ffff888075c7e780 which belongs to the cache io_kiocb of size 248 The buggy address is located 68 bytes inside of freed 248-byte region [ffff888075c7e780, ffff888075c7e878) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75c7e memcg:ffff88803381b501 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff888145ae7280 ffffea0001d71fc0 0000000000000006 raw: 0000000000000000 00000000000c000c 00000000f5000000 ffff88803381b501 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 6107, tgid 6077 (syz.2.27), ts 106304952041, free_ts 97893783911 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:3023 [inline] allocate_slab+0x96/0x3a0 mm/slub.c:3196 new_slab mm/slub.c:3250 [inline] ___slab_alloc+0xe94/0x1920 mm/slub.c:4626 __kmem_cache_alloc_bulk+0x1e2/0x590 mm/slub.c:7322 kmem_cache_alloc_bulk_noprof+0x3bd/0x5d0 mm/slub.c:7402 __io_alloc_req_refill+0x9d/0x340 io_uring/io_uring.c:1060 io_alloc_req io_uring/io_uring.h:543 [inline] io_submit_sqes+0xc29/0x1e60 io_uring/io_uring.c:2438 __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 15 tgid 15 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 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x286/0x870 kernel/softirq.c:579 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 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: ffff888075c7e680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888075c7e700: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc >ffff888075c7e780: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888075c7e800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc ffff888075c7e880: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ==================================================================