Code: ff 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 7c 24 f0 48 89 74 24 e8 48 89 54 24 e0 48 8b 44 24 f0 48 8b 54 24 e8 48 8b 4c 24 e0 <8b> b0 0c 01 00 00 f3 0f 6f 01 c1 e6 04 0f 11 02 f3 0f 6f 49 10 81 ================================================================== BUG: KASAN: use-after-free in io_fallback_tw+0x6d/0x119 io_uring/io_uring.c:1249 Read of size 8 at addr ffff888028d33948 by task syz-executor371/5070 CPU: 1 PID: 5070 Comm: syz-executor371 Not tainted 6.2.0-rc3-next-20230112-syzkaller #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:1249 tctx_task_work.cold+0xf/0x2c io_uring/io_uring.c:1219 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 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:310 exc_page_fault+0xc0/0x170 arch/x86/mm/fault.c:1557 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0033:0x7ff7d332e08e Code: Unable to access opcode bytes at 0x7ff7d332e064. RSP: 002b:00007fffc08a9bc8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ff7d332f1e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff7d332f270 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 5070: 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:1062 io_alloc_req_refill io_uring/io_uring.h:348 [inline] io_submit_sqes.cold+0x7c/0xc2 io_uring/io_uring.c:2407 __do_sys_io_uring_enter+0x9e4/0x2c10 io_uring/io_uring.c:3429 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:2737 io_ring_exit_work+0x2e7/0xc80 io_uring/io_uring.c:2967 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 ffff888028d338c0 which belongs to the cache io_kiocb of size 216 The buggy address is located 136 bytes inside of 216-byte region [ffff888028d338c0, ffff888028d33998) The buggy address belongs to the physical page: page:ffffea0000a34cc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28d33 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffff88814633b280 dead000000000122 0000000000000000 raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 5070, tgid 5070 (syz-executor371), ts 55651699541, free_ts 55645844106 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:1062 io_alloc_req_refill io_uring/io_uring.h:348 [inline] io_submit_sqes.cold+0x7c/0xc2 io_uring/io_uring.c:2407 __do_sys_io_uring_enter+0x9e4/0x2c10 io_uring/io_uring.c:3429 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_list+0x176/0xcd0 mm/page_alloc.c:3528 release_pages+0xcb1/0x1330 mm/swap.c:1072 tlb_batch_pages_flush+0xa8/0x1a0 mm/mmu_gather.c:97 tlb_flush_mmu_free mm/mmu_gather.c:292 [inline] tlb_flush_mmu mm/mmu_gather.c:299 [inline] tlb_finish_mmu+0x14b/0x7e0 mm/mmu_gather.c:391 exit_mmap+0x202/0x7c0 mm/mmap.c:3100 __mmput+0x128/0x4c0 kernel/fork.c:1212 mmput+0x60/0x70 kernel/fork.c:1234 exec_mmap fs/exec.c:1034 [inline] begin_new_exec+0x1027/0x2f80 fs/exec.c:1293 load_elf_binary+0x801/0x4ff0 fs/binfmt_elf.c:1001 search_binary_handler fs/exec.c:1736 [inline] exec_binprm fs/exec.c:1778 [inline] bprm_execve fs/exec.c:1853 [inline] bprm_execve+0x7fd/0x1ae0 fs/exec.c:1809 do_execveat_common+0x72c/0x880 fs/exec.c:1960 do_execve fs/exec.c:2034 [inline] __do_sys_execve fs/exec.c:2110 [inline] __se_sys_execve fs/exec.c:2105 [inline] __x64_sys_execve+0x93/0xc0 fs/exec.c:2105 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 Memory state around the buggy address: ffff888028d33800: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff888028d33880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff888028d33900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888028d33980: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888028d33a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== ---------------- Code disassembly (best guess): 0: ff 66 2e jmpq *0x2e(%rsi) 3: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) a: 00 b: 90 nop c: 48 89 7c 24 f0 mov %rdi,-0x10(%rsp) 11: 48 89 74 24 e8 mov %rsi,-0x18(%rsp) 16: 48 89 54 24 e0 mov %rdx,-0x20(%rsp) 1b: 48 8b 44 24 f0 mov -0x10(%rsp),%rax 20: 48 8b 54 24 e8 mov -0x18(%rsp),%rdx 25: 48 8b 4c 24 e0 mov -0x20(%rsp),%rcx * 2a: 8b b0 0c 01 00 00 mov 0x10c(%rax),%esi <-- trapping instruction 30: f3 0f 6f 01 movdqu (%rcx),%xmm0 34: c1 e6 04 shl $0x4,%esi 37: 0f 11 02 movups %xmm0,(%rdx) 3a: f3 0f 6f 49 10 movdqu 0x10(%rcx),%xmm1 3f: 81 .byte 0x81