syzbot has found a reproducer for the following issue on: HEAD commit: 0a093b2893c7 Add linux-next specific files for 20230112 git tree: linux-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=176167ba480000 kernel config: https://syzkaller.appspot.com/x/.config?x=835f3591019836d5 dashboard link: https://syzkaller.appspot.com/bug?extid=bc022c162e3b001bf607 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17d58fbe480000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=151b0316480000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/8111a570d6cb/disk-0a093b28.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/ecc135b7fc9a/vmlinux-0a093b28.xz kernel image: https://storage.googleapis.com/syzbot-assets/ca8d73b446ea/bzImage-0a093b28.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+bc022c162e3b001bf607@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in io_fallback_req_func+0xc7/0x204 io_uring/io_uring.c:251 Read of size 8 at addr ffff8880793aa948 by task kworker/0:3/4401 CPU: 0 PID: 4401 Comm: kworker/0:3 Not tainted 6.2.0-rc3-next-20230112-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: events io_fallback_req_func Call Trace: <TASK> __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_req_func+0xc7/0x204 io_uring/io_uring.c:251 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 </TASK> Allocated by task 5077: 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 31: 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 ffff8880793aa8c0 which belongs to the cache io_kiocb of size 216 The buggy address is located 136 bytes inside of 216-byte region [ffff8880793aa8c0, ffff8880793aa998) The buggy address belongs to the physical page: page:ffffea0001e4ea80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x793aa flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffff88814610fc80 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 5077, tgid 5077 (syz-executor134), ts 60034717602, free_ts 59988620363 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 exit_mm kernel/exit.c:563 [inline] do_exit+0x9ac/0x2a90 kernel/exit.c:854 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 Memory state around the buggy address: ffff8880793aa800: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff8880793aa880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff8880793aa900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880793aa980: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880793aaa00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================
