kobject_add_internal failed for 43:0 with -EEXIST, don't try to register things with the same name in the same directory. ------------[ cut here ]------------ WARNING: CPU: 1 PID: 17448 at block/genhd.c:523 __device_add_disk+0xb76/0xd10 block/genhd.c:523 Modules linked in: CPU: 1 PID: 17448 Comm: syz-executor.4 Not tainted 5.14.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__device_add_disk+0xb76/0xd10 block/genhd.c:523 Code: fb ff ff 4c 89 ef 89 44 24 28 e8 85 8a f6 fd 8b 44 24 28 e9 7a fb ff ff 4c 89 ef e8 04 8a f6 fd e9 e0 fb ff ff e8 2a fa af fd <0f> 0b e9 97 fb ff ff 4c 89 ff e8 1b 8a f6 fd e9 b1 f6 ff ff 48 8b RSP: 0018:ffffc9000187f3f0 EFLAGS: 00010246 RAX: 0000000000040000 RBX: ffff888145955800 RCX: ffffc9001254b000 RDX: 0000000000040000 RSI: ffffffff83c5b396 RDI: 0000000000000003 RBP: ffff8880135a1800 R08: 0000000000000000 R09: ffffffff8fced8ff R10: ffffffff83c5af28 R11: 0000000000000000 R12: 0000000000000001 R13: ffff888145955c9c R14: ffff8880135a18a0 R15: 0000000000000000 FS: 00007f04b2848700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd9c1ebb000 CR3: 000000002694b000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: add_disk include/linux/genhd.h:217 [inline] nbd_dev_add+0x73f/0x940 drivers/block/nbd.c:1733 nbd_genl_connect+0x551/0x1820 drivers/block/nbd.c:1842 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline] genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2403 ___sys_sendmsg+0xf3/0x170 net/socket.c:2457 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486 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 RIP: 0033:0x4665e9 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:00007f04b2848188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9 RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000007 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038 R13: 00007ffc6f045c5f R14: 00007f04b2848300 R15: 0000000000022000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: ff 4c 89 ef decl -0x11(%rcx,%rcx,4) 4: 89 44 24 28 mov %eax,0x28(%rsp) 8: e8 85 8a f6 fd callq 0xfdf68a92 d: 8b 44 24 28 mov 0x28(%rsp),%eax 11: e9 7a fb ff ff jmpq 0xfffffb90 16: 4c 89 ef mov %r13,%rdi 19: e8 04 8a f6 fd callq 0xfdf68a22 1e: e9 e0 fb ff ff jmpq 0xfffffc03 23: e8 2a fa af fd callq 0xfdaffa52 28: 0f 0b ud2 <-- trapping instruction 2a: e9 97 fb ff ff jmpq 0xfffffbc6 2f: 4c 89 ff mov %r15,%rdi 32: e8 1b 8a f6 fd callq 0xfdf68a52 37: e9 b1 f6 ff ff jmpq 0xfffff6ed 3c: 48 rex.W 3d: 8b .byte 0x8b