================================================================== BUG: KASAN: use-after-free in io_fallback_tw+0x6d/0x119 io_uring/io_uring.c:1253 Read of size 8 at addr ffff888029b7c948 by task syz-executor.0/5601 CPU: 1 PID: 5601 Comm: syz-executor.0 Not tainted 6.2.0-rc3-next-20230112-syzkaller-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 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_fallback_tw+0x6d/0x119 io_uring/io_uring.c:1253 tctx_task_work.cold+0xf/0x2c io_uring/io_uring.c:1223 task_work_run+0x16f/0x270 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xb17/0x2a90 kernel/exit.c:867 do_group_exit+0xd4/0x2a0 kernel/exit.c:1012 get_signal+0x225f/0x24f0 kernel/signal.c:2859 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f9fa6c8c0c9 Code: Unable to access opcode bytes at 0x7f9fa6c8c09f. RSP: 002b:00007f9fa7a98168 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: fffffffffffffe00 RBX: 00007f9fa6dabf80 RCX: 00007f9fa6c8c0c9 RDX: 0000000000002020 RSI: 00000000200021c0 RDI: 0000000000000006 RBP: 00007f9fa6ce7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdca0565bf R14: 00007f9fa7a98300 R15: 0000000000022000 Allocated by task 5601: 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] kmem_cache_alloc_bulk+0x3aa/0x730 mm/slub.c:4033 __io_alloc_req_refill+0xcc/0x40b io_uring/io_uring.c:1064 io_alloc_req_refill io_uring/io_uring.h:348 [inline] io_submit_sqes.cold+0x7c/0xc2 io_uring/io_uring.c:2412 __do_sys_io_uring_enter+0x9e4/0x2c10 io_uring/io_uring.c:3434 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 33: 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 io_req_caches_free+0x1a9/0x1e6 io_uring/io_uring.c:2742 io_ring_exit_work+0x2e7/0xc80 io_uring/io_uring.c:2972 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 The buggy address belongs to the object at ffff888029b7c8c0 which belongs to the cache io_kiocb of size 224 The buggy address is located 136 bytes inside of 224-byte region [ffff888029b7c8c0, ffff888029b7c9a0) The buggy address belongs to the physical page: page:ffffea0000a6df00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29b7c memcg:ffff88801de69981 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffff888146395500 dead000000000122 0000000000000000 raw: 0000000000000000 00000000800c000c 00000001ffffffff ffff88801de69981 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 5601, tgid 5600 (syz-executor.0), ts 79202512513, free_ts 51400073995 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 __kmem_cache_alloc_bulk mm/slub.c:3951 [inline] kmem_cache_alloc_bulk+0x23d/0x730 mm/slub.c:4026 __io_alloc_req_refill+0xcc/0x40b io_uring/io_uring.c:1064 io_alloc_req_refill io_uring/io_uring.h:348 [inline] io_submit_sqes.cold+0x7c/0xc2 io_uring/io_uring.c:2412 __do_sys_io_uring_enter+0x9e4/0x2c10 io_uring/io_uring.c:3434 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 __vunmap+0x7fe/0xc00 mm/vmalloc.c:2746 __vfree+0x3c/0xd0 mm/vmalloc.c:2794 vfree+0x5e/0x90 mm/vmalloc.c:2825 kcov_put kernel/kcov.c:428 [inline] kcov_put+0x26/0x40 kernel/kcov.c:424 kcov_close+0x10/0x20 kernel/kcov.c:524 __fput+0x27c/0xa90 fs/file_table.c:321 task_work_run+0x16f/0x270 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xb17/0x2a90 kernel/exit.c:867 do_group_exit+0xd4/0x2a0 kernel/exit.c:1012 get_signal+0x225f/0x24f0 kernel/signal.c:2859 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 Memory state around the buggy address: ffff888029b7c800: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff888029b7c880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff888029b7c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888029b7c980: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ffff888029b7ca00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================