================================================================== BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline] BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:27 [inline] BUG: KASAN: use-after-free in refcount_dec_not_one+0x71/0x1e0 lib/refcount.c:76 Read of size 4 at addr ffff888143f101a0 by task syz-executor.0/16222 CPU: 0 PID: 16222 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230 __kasan_report mm/kasan/report.c:397 [inline] kasan_report.cold+0x79/0xd5 mm/kasan/report.c:414 check_region_inline mm/kasan/generic.c:179 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:185 instrument_atomic_read include/linux/instrumented.h:71 [inline] atomic_read include/asm-generic/atomic-instrumented.h:27 [inline] refcount_dec_not_one+0x71/0x1e0 lib/refcount.c:76 refcount_dec_and_mutex_lock+0x19/0x140 lib/refcount.c:115 nbd_put drivers/block/nbd.c:248 [inline] nbd_genl_connect+0xeed/0x1570 drivers/block/nbd.c:1960 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739 genl_family_rcv_msg net/netlink/genetlink.c:783 [inline] genl_rcv_msg+0x32f/0x590 net/netlink/genetlink.c:800 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502 genl_rcv+0x24/0x40 net/netlink/genetlink.c:811 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2437 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x465f69 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9969939188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465f69 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005 RBP: 00000000004bfa67 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffcf8acfcbf R14: 00007f9969939300 R15: 0000000000022000 Allocated by task 1: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:400 [inline] ____kasan_kmalloc.constprop.0+0x82/0xa0 mm/kasan/common.c:428 kmalloc include/linux/slab.h:554 [inline] kzalloc include/linux/slab.h:684 [inline] nbd_dev_add+0x44/0x910 drivers/block/nbd.c:1653 nbd_init+0x251/0x272 drivers/block/nbd.c:2374 do_one_initcall+0x103/0x650 init/main.c:1221 do_initcall_level init/main.c:1294 [inline] do_initcalls init/main.c:1310 [inline] do_basic_setup init/main.c:1330 [inline] kernel_init_freeable+0x63e/0x6c2 init/main.c:1531 kernel_init+0xd/0x1b8 init/main.c:1419 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Freed by task 16222: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:356 ____kasan_slab_free+0xe1/0x110 mm/kasan/common.c:361 kasan_slab_free include/linux/kasan.h:191 [inline] slab_free_hook mm/slub.c:1561 [inline] slab_free_freelist_hook+0x6b/0x160 mm/slub.c:1594 slab_free mm/slub.c:3146 [inline] kfree+0xdb/0x3e0 mm/slub.c:4182 nbd_dev_remove drivers/block/nbd.c:243 [inline] nbd_put.part.0+0x18c/0x1e0 drivers/block/nbd.c:251 nbd_put drivers/block/nbd.c:295 [inline] nbd_config_put+0x701/0x8f0 drivers/block/nbd.c:1242 nbd_genl_connect+0xebd/0x1570 drivers/block/nbd.c:1958 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739 genl_family_rcv_msg net/netlink/genetlink.c:783 [inline] genl_rcv_msg+0x32f/0x590 net/netlink/genetlink.c:800 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502 genl_rcv+0x24/0x40 net/netlink/genetlink.c:811 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2437 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff888143f10000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 416 bytes inside of 1024-byte region [ffff888143f10000, ffff888143f10400) The buggy address belongs to the page: page:00000000798e8e71 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888143f12800 pfn:0x143f10 head:00000000798e8e71 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x57ff00000010200(slab|head) raw: 057ff00000010200 ffffea0005042208 ffff888140000888 ffff888010c41dc0 raw: ffff888143f12800 0000000000100004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888143f10080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888143f10100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888143f10180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888143f10200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888143f10280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================