================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:185 [inline] BUG: KASAN: use-after-free in atomic_read arch/x86/include/asm/atomic.h:27 [inline] BUG: KASAN: use-after-free in refcount_dec_not_one+0x9a/0xc0 lib/refcount.c:270 Read of size 4 at addr ffff8880a97d0918 by task syz-executor332/10934 CPU: 0 PID: 10934 Comm: syz-executor332 Not tainted 4.14.307-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:251 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:350 kasan_report mm/kasan/report.c:408 [inline] __asan_report_load4_noabort+0x68/0x70 mm/kasan/report.c:428 __read_once_size include/linux/compiler.h:185 [inline] atomic_read arch/x86/include/asm/atomic.h:27 [inline] refcount_dec_not_one+0x9a/0xc0 lib/refcount.c:270 refcount_dec_and_mutex_lock+0x1a/0x60 lib/refcount.c:309 nbd_put drivers/block/nbd.c:228 [inline] nbd_genl_connect+0xce1/0x13e0 drivers/block/nbd.c:1905 genl_family_rcv_msg+0x572/0xb20 net/netlink/genetlink.c:600 genl_rcv_msg+0xaf/0x140 net/netlink/genetlink.c:625 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2461 genl_rcv+0x24/0x40 net/netlink/genetlink.c:636 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x651/0xbc0 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062 __sys_sendmsg+0xa3/0x120 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2103 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 RIP: 0033:0x7fe68e699f69 RSP: 002b:00007ffff3e070b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000000c750 RCX: 00007fe68e699f69 RDX: 0000000000000000 RSI: 0000000020000900 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffff3e070e0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffff3e070dc R13: 00007ffff3e07110 R14: 00007ffff3e070f0 R15: 0000000000000184 Allocated by task 10931: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] kzalloc include/linux/slab.h:661 [inline] nbd_dev_add+0x7c/0x800 drivers/block/nbd.c:1619 nbd_genl_connect+0x3a4/0x13e0 drivers/block/nbd.c:1764 genl_family_rcv_msg+0x572/0xb20 net/netlink/genetlink.c:600 genl_rcv_msg+0xaf/0x140 net/netlink/genetlink.c:625 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2461 genl_rcv+0x24/0x40 net/netlink/genetlink.c:636 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x651/0xbc0 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062 __sys_sendmsg+0xa3/0x120 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2103 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 Freed by task 10934: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xc9/0x250 mm/slab.c:3815 nbd_dev_remove drivers/block/nbd.c:223 [inline] nbd_put.part.0+0x100/0x140 drivers/block/nbd.c:231 nbd_put drivers/block/nbd.c:267 [inline] nbd_config_put+0x51c/0x6c0 drivers/block/nbd.c:1172 nbd_genl_connect+0xcb9/0x13e0 drivers/block/nbd.c:1903 genl_family_rcv_msg+0x572/0xb20 net/netlink/genetlink.c:600 genl_rcv_msg+0xaf/0x140 net/netlink/genetlink.c:625 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2461 genl_rcv+0x24/0x40 net/netlink/genetlink.c:636 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x651/0xbc0 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062 __sys_sendmsg+0xa3/0x120 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2103 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 The buggy address belongs to the object at ffff8880a97d0840 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 216 bytes inside of 512-byte region [ffff8880a97d0840, ffff8880a97d0a40) The buggy address belongs to the page: page:ffffea0002a5f400 count:1 mapcount:0 mapping:ffff8880a97d00c0 index:0xffff8880a97d0340 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffff8880a97d00c0 ffff8880a97d0340 0000000100000005 raw: ffffea00027aa1a0 ffffea00028dfae0 ffff88813fe74940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a97d0800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8880a97d0880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a97d0900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a97d0980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a97d0a00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================