================================================================== BUG: KASAN: use-after-free in __io_remove_buffers.part.0+0x32c/0x470 fs/io_uring.c:4972 Read of size 2 at addr ffff88807b9a9012 by task kworker/u4:3/500 CPU: 1 PID: 500 Comm: kworker/u4:3 Not tainted 5.18.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Workqueue: events_unbound io_ring_exit_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x57/0x7d lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313 print_report mm/kasan/report.c:429 [inline] kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491 __io_remove_buffers.part.0+0x32c/0x470 fs/io_uring.c:4972 __io_remove_buffers fs/io_uring.c:10292 [inline] io_destroy_buffers fs/io_uring.c:10295 [inline] io_ring_ctx_free fs/io_uring.c:10376 [inline] io_ring_exit_work+0x757/0xc5f fs/io_uring.c:10555 process_one_work+0x865/0x13d0 kernel/workqueue.c:2289 worker_thread+0x598/0xec0 kernel/workqueue.c:2436 kthread+0x299/0x340 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Allocated by task 4080: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc mm/kasan/common.c:515 [inline] ____kasan_kmalloc mm/kasan/common.c:474 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524 kcalloc include/linux/slab.h:652 [inline] io_init_bl_list+0x1f/0xea fs/io_uring.c:5133 io_register_pbuf_ring fs/io_uring.c:12153 [inline] __io_uring_register fs/io_uring.c:12344 [inline] __do_sys_io_uring_register.cold+0x495/0xcba fs/io_uring.c:12380 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 4080: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3510 [inline] kfree+0xd6/0x4d0 mm/slub.c:4552 io_register_pbuf_ring fs/io_uring.c:12171 [inline] __io_uring_register fs/io_uring.c:12344 [inline] __do_sys_io_uring_register+0x1557/0x19d0 fs/io_uring.c:12380 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff88807b9a9000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 18 bytes inside of 2048-byte region [ffff88807b9a9000, ffff88807b9a9800) The buggy address belongs to the physical page: page:ffffea0001ee6a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7b9a8 head:ffffea0001ee6a00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888010842000 raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3594, tgid 3594 (syz-executor.0), ts 43160208108, free_ts 35760742800 prep_new_page mm/page_alloc.c:2441 [inline] get_page_from_freelist+0x178d/0x3dc0 mm/page_alloc.c:4182 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5408 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab+0x26c/0x3c0 mm/slub.c:1944 new_slab mm/slub.c:2004 [inline] ___slab_alloc+0x8e1/0xf20 mm/slub.c:3005 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3092 slab_alloc_node mm/slub.c:3183 [inline] slab_alloc mm/slub.c:3225 [inline] kmem_cache_alloc_trace+0x310/0x3f0 mm/slub.c:3256 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:714 [inline] ipv6_add_dev+0xcc/0x10f0 net/ipv6/addrconf.c:378 addrconf_notify+0x5b7/0x15a0 net/ipv6/addrconf.c:3521 notifier_call_chain+0x94/0x170 kernel/notifier.c:84 call_netdevice_notifiers_extack net/core/dev.c:1976 [inline] call_netdevice_notifiers net/core/dev.c:1990 [inline] register_netdevice+0xd6f/0x1400 net/core/dev.c:9994 __rtnl_newlink+0x10a4/0x13f0 net/core/rtnetlink.c:3485 rtnl_newlink+0x5a/0x90 net/core/rtnetlink.c:3531 rtnetlink_rcv_msg+0x31d/0x8d0 net/core/rtnetlink.c:5993 netlink_rcv_skb+0x118/0x370 net/netlink/af_netlink.c:2503 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x433/0x710 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x770/0xc20 net/netlink/af_netlink.c:1921 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1356 [inline] free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1406 free_unref_page_prepare mm/page_alloc.c:3328 [inline] free_unref_page+0x19/0x6a0 mm/page_alloc.c:3423 folio_put include/linux/mm.h:1200 [inline] put_page include/linux/mm.h:1233 [inline] __skb_frag_unref include/linux/skbuff.h:3330 [inline] skb_release_data+0x3db/0x650 net/core/skbuff.c:672 skb_release_all net/core/skbuff.c:742 [inline] __kfree_skb+0x39/0x50 net/core/skbuff.c:756 __sk_defer_free_flush net/ipv4/tcp.c:1601 [inline] sk_defer_free_flush include/net/tcp.h:1380 [inline] tcp_recvmsg+0x17f/0x4b0 net/ipv4/tcp.c:2577 inet_recvmsg+0xf2/0x490 net/ipv4/af_inet.c:850 sock_recvmsg_nosec net/socket.c:948 [inline] sock_recvmsg net/socket.c:966 [inline] sock_recvmsg net/socket.c:962 [inline] sock_read_iter+0x2ae/0x3f0 net/socket.c:1039 call_read_iter include/linux/fs.h:2044 [inline] new_sync_read+0x413/0x510 fs/read_write.c:401 vfs_read+0x378/0x4b0 fs/read_write.c:482 ksys_read+0x16b/0x1c0 fs/read_write.c:620 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff88807b9a8f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807b9a8f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807b9a9000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807b9a9080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807b9a9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================