================================================================== BUG: KASAN: use-after-free in io_fallback_req_func+0xc7/0x204 io_uring/io_uring.c:251 Read of size 8 at addr ffff8880752e4948 by task kworker/0:6/5169 CPU: 0 PID: 5169 Comm: kworker/0:6 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: __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 Allocated by task 6976: 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 5772: 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 ffff8880752e48c0 which belongs to the cache io_kiocb of size 216 The buggy address is located 136 bytes inside of 216-byte region [ffff8880752e48c0, ffff8880752e4998) The buggy address belongs to the physical page: page:ffffea0001d4b900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x752e4 memcg:ffff8880752e6a01 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffff88801c0a8dc0 dead000000000122 0000000000000000 raw: 0000000000000000 00000000000c000c 00000001ffffffff ffff8880752e6a01 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 5298, tgid 5295 (syz-executor.3), ts 141452820929, free_ts 135735379231 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+0x1d/0x490 mm/page_alloc.c:3482 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2637 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x192/0x220 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x63/0x90 mm/kasan/common.c:302 kasan_slab_alloc include/linux/kasan.h:186 [inline] slab_post_alloc_hook mm/slab.h:769 [inline] slab_alloc_node mm/slub.c:3452 [inline] slab_alloc mm/slub.c:3460 [inline] __kmem_cache_alloc_lru mm/slub.c:3467 [inline] kmem_cache_alloc+0x175/0x320 mm/slub.c:3476 getname_flags.part.0+0x50/0x4f0 fs/namei.c:140 getname_flags include/linux/audit.h:320 [inline] getname+0x92/0xd0 fs/namei.c:219 do_sys_openat2+0xf5/0x4c0 fs/open.c:1305 do_sys_open fs/open.c:1327 [inline] __do_sys_openat fs/open.c:1343 [inline] __se_sys_openat fs/open.c:1338 [inline] __x64_sys_openat+0x143/0x1f0 fs/open.c:1338 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: ffff8880752e4800: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff8880752e4880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff8880752e4900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880752e4980: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880752e4a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================