bisecting cause commit starting from 6fbd15c096919388c7c2bdf54574d4e99534af25 building syzkaller on fcc6d71be2c3ce7d9305c04fc2e87af554571bac testing commit 6fbd15c096919388c7c2bdf54574d4e99534af25 with gcc (GCC) 10.2.1 20210217 kernel signature: 983bc3b1984a2a2c66a8fea826c6fb20ec7426041b439022347acb284690f92b all runs: crashed: WARNING in nbd_dev_add testing release v5.11 testing commit f40ddce88593482919761f74910f42f4b84c004b with gcc (GCC) 10.2.1 20210217 kernel signature: cac7c61a707d8a4a548eba05d19c3df8eb3d1ebca04215b962b8d0fa4397b1a1 all runs: crashed: WARNING in nbd_dev_add testing release v5.10 testing commit 2c85ebc57b3e1817b6ce1a6b703928e113a90442 with gcc (GCC) 10.2.1 20210217 kernel signature: ad0020076c568fd04e3712999367961eadbdf96cf6f928f88e3fec927cee834c all runs: crashed: WARNING in nbd_dev_add testing release v5.9 testing commit bbf5c979011a099af5dc76498918ed7df445635b with gcc (GCC) 10.2.1 20210217 kernel signature: 146ea8d61e7d778cc2e3add7c28d140006fdf1a37baf6454f73000c8aae324f8 all runs: crashed: WARNING in nbd_dev_add testing release v5.8 testing commit bcf876870b95592b52519ed4aafcf9d95999bc9c with gcc (GCC) 8.4.1 20210217 kernel signature: 3026bb0a2d3a4e46ba6ebc016471b2198916b1a4253f6f438d502ead43644cf9 all runs: crashed: WARNING in nbd_dev_add testing release v5.7 testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.4.1 20210217 kernel signature: 30805e1918ab19740b728af479d23c466a1509b15d5066c42346b60bba1acc06 all runs: crashed: WARNING in nbd_dev_add testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.4.1 20210217 kernel signature: b552afeb3d9badde6b049d25a1896276c34501ddca9e79eecf22939451ca8622 all runs: crashed: WARNING in nbd_dev_add testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.4.1 20210217 kernel signature: c678fb33d6b02ef5ae95e66af3cbdfb9c5dfd670a92997301396b81f5ef3bd36 all runs: crashed: WARNING in nbd_dev_add testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.4.1 20210217 kernel signature: 52ee41a4adefe6c200ca1c1aab7fd66b4c0527ed54579d56d21c5bef1e0aef1f all runs: crashed: WARNING in nbd_dev_add testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.4.1 20210217 kernel signature: 2129567d001f6bf628693539bc74663811aba0e449fce0f52db8bd19960b7d21 all runs: boot failed: BUG: spinlock bad magic in nf_connlabels_get testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.4.1 20210217 kernel signature: 2bd85848c8e605bab2e10a90f90e74378c1715b26b5be1e5dcf483b5a717ff21 all runs: boot failed: can't ssh into the instance testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.4.1 20210217 kernel signature: ce644b2db00fa15d7c22357e49973eb6406746b7dd6a92d876a43edb148d7304 all runs: boot failed: can't ssh into the instance testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.4.1 20210217 kernel signature: 501fdb7cb93a091558ce72cf71a78f666f358922c87ee9a4f9f54b15f153bcfb all runs: boot failed: can't ssh into the instance testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.4.1 20210217 kernel signature: 0894f4d55d7d31426b4e5e8b02224b03c52ce55658406914ace2ee06e1ea1f3c all runs: boot failed: can't ssh into the instance testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.4.1 20210217 kernel signature: fc768325776fd3e89ea3ea135abba2c6df8d2f62ce41a57df14d8bde1d90cdfa all runs: boot failed: can't ssh into the instance testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.4.1 20210217 kernel signature: b63a5c020e3f4add0e1ef39fb14558f6c1deccf4dd43b9b3eb7d145d572a7d8d all runs: boot failed: can't ssh into the instance testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.4.1 20210217 failed to run ["make" "-j" "64" "ARCH=x86_64" "CC=/syzkaller/shared/bisect_bin/gcc-8.1.0/bin/gcc" "bzImage"]: exit status 2 testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.4.1 20210217 orc_dump.c:106:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] orc_dump.c:111:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] elf.c:135:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:140:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.4.1 20210217 orc_dump.c:106:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] orc_dump.c:111:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] elf.c:135:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:140:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] pager.c:36:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.4.1 20210217 orc_dump.c:105:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] orc_dump.c:110:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] pager.c:36:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] elf.c:134:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:139:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.4.1 20210217 pager.c:35:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] elf.c:144:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:149:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.4.1 20210217 pager.c:35:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] elf.c:141:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:146:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] testing release v4.11 testing commit a351e9b9fc24e982ec2f0e76379a49826036da12 with gcc (GCC) 7.5.0 elf.c:141:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:146:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] pager.c:35:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] testing release v4.10 testing commit c470abd4fde40ea6a0846a2beab642a578c0b8cd with gcc (GCC) 5.5.0 tools/include/linux/log2.h:19:1: error: ignoring attribute 'noreturn' because it conflicts with attribute 'const' [-Werror=attributes] elf.c:129:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:134:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] pager.c:35:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 tools/include/linux/log2.h:19:1: error: ignoring attribute 'noreturn' because it conflicts with attribute 'const' [-Werror=attributes] pager.c:35:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] elf.c:129:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:134:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 tools/include/linux/log2.h:19:1: error: ignoring attribute 'noreturn' because it conflicts with attribute 'const' [-Werror=attributes] elf.c:129:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:134:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] pager.c:33:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 tools/include/linux/log2.h:19:1: error: ignoring attribute 'noreturn' because it conflicts with attribute 'const' [-Werror=attributes] elf.c:122:2: error: 'elf_getshnum' is deprecated [-Werror=deprecated-declarations] elf.c:127:2: error: 'elf_getshstrndx' is deprecated [-Werror=deprecated-declarations] pager.c:33:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 tools/include/linux/log2.h:19:1: error: ignoring attribute 'noreturn' because it conflicts with attribute 'const' [-Werror=attributes] pager.c:33:12: error: passing argument 2 to 'restrict'-qualified parameter aliases with argument 4 [-Werror=restrict] revisions tested: 16, total time: 3h50m38.167279178s (build: 2h5m44.637690604s, test: 1h40m44.830839362s) the crash already happened on the oldest tested release commit msg: Linux 5.4 crash: WARNING in nbd_dev_add RBP: 00000000004bcd1c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffd1e6aef2f R14: 00007fb5cb2a8300 R15: 0000000000022000 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: 0 PID: 10721 at block/genhd.c:741 register_disk block/genhd.c:613 [inline] WARNING: CPU: 0 PID: 10721 at block/genhd.c:741 __device_add_disk+0xca7/0xf30 block/genhd.c:745 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 10721 Comm: syz-executor.1 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x96/0xe0 lib/dump_stack.c:118 panic+0x2a1/0x52a kernel/panic.c:221 __warn.cold.10+0x25/0x25 kernel/panic.c:582 report_bug+0x1aa/0x260 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:179 [inline] fixup_bug arch/x86/kernel/traps.c:174 [inline] do_error_trap+0x12d/0x1e0 arch/x86/kernel/traps.c:272 do_invalid_op+0x31/0x40 arch/x86/kernel/traps.c:291 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028 RIP: 0010:__device_add_disk+0xca7/0xf30 block/genhd.c:741 Code: 83 e2 07 38 d0 7f 08 84 c0 0f 85 5c 02 00 00 41 80 a6 cc 00 00 00 ef e9 b3 f9 ff ff 0f 0b e9 e6 f9 ff ff 0f 0b e9 05 f7 ff ff <0f> 0b e9 dd fb ff ff 48 89 ef e8 da bf 3d fe e9 7b f4 ff ff e8 b0 RSP: 0018:ffff888088df7390 EFLAGS: 00010282 RAX: 00000000ffffffef RBX: 1ffff110111bee7a RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff88808b373a14 RBP: ffff88808a818608 R08: fffffbfff1bd9b3e R09: fffffbfff1bd9b3e R10: fffffbfff1bd9b3d R11: ffffffff8decd9ef R12: ffff88808a818090 R13: 0000000000000001 R14: ffff88808a818000 R15: ffff88808a818004 add_disk include/linux/genhd.h:429 [inline] nbd_dev_add+0x6e9/0x820 drivers/block/nbd.c:1720 nbd_genl_connect+0x494/0x122d drivers/block/nbd.c:1837 genl_family_rcv_msg+0x5ff/0xf40 net/netlink/genetlink.c:629 genl_rcv_msg+0xb3/0x160 net/netlink/genetlink.c:654 netlink_rcv_skb+0x119/0x340 net/netlink/af_netlink.c:2477 genl_rcv+0x1f/0x30 net/netlink/genetlink.c:665 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x3fc/0x5c0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x71e/0xb70 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:657 ___sys_sendmsg+0x653/0x950 net/socket.c:2311 __sys_sendmsg+0xce/0x170 net/socket.c:2356 do_syscall_64+0x8e/0x4e0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465ef9 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:00007fb5cb2a8188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465ef9 RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000005 RBP: 00000000004bcd1c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffd1e6aef2f R14: 00007fb5cb2a8300 R15: 0000000000022000 Kernel Offset: disabled Rebooting in 86400 seconds..