================================================================== 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 ffff8880aea40b18 by task syz-executor.0/10219 CPU: 0 PID: 10219 Comm: syz-executor.0 Not tainted 4.14.295-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 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:252 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351 kasan_report mm/kasan/report.c:409 [inline] __asan_report_load4_noabort+0x68/0x70 mm/kasan/report.c:429 __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: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:2454 genl_rcv+0x24/0x40 net/netlink/genetlink.c:636 netlink_unicast_kernel net/netlink/af_netlink.c:1296 [inline] netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1322 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1893 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+0x46/0xbb RIP: 0033:0x7f7bb4f965a9 RSP: 002b:00007f7bb3909168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f7bb50b6f80 RCX: 00007f7bb4f965a9 RDX: 0000000000000000 RSI: 0000000020000380 RDI: 0000000000000005 RBP: 00007f7bb4ff1580 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffb2954b1f R14: 00007f7bb3909300 R15: 0000000000022000 Allocated by task 1: 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:1617 nbd_init+0x15b/0x17a drivers/block/nbd.c:2310 do_one_initcall+0x88/0x210 init/main.c:830 do_initcall_level init/main.c:896 [inline] do_initcalls init/main.c:904 [inline] do_basic_setup init/main.c:922 [inline] kernel_init_freeable+0x565/0x626 init/main.c:1081 kernel_init+0xd/0x161 init/main.c:1006 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Freed by task 10219: 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:1901 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:2454 genl_rcv+0x24/0x40 net/netlink/genetlink.c:636 netlink_unicast_kernel net/netlink/af_netlink.c:1296 [inline] netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1322 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1893 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+0x46/0xbb The buggy address belongs to the object at ffff8880aea40a40 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 216 bytes inside of 512-byte region [ffff8880aea40a40, ffff8880aea40c40) The buggy address belongs to the page: page:ffffea0002ba9000 count:1 mapcount:0 mapping:ffff8880aea40040 index:0x0 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffff8880aea40040 0000000000000000 0000000100000006 raw: ffffea0002bb9260 ffffea0002ba9420 ffff88813fe74940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880aea40a00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8880aea40a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880aea40b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880aea40b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880aea40c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================