Greeting, FYI, we noticed the following commit (built with gcc-9): commit: 6243580a0dc1a7043af67b983a94e4c927fb4e75 ("block: remove __sync_blockdev") git://git.infradead.org/users/hch/block.git block-cleanups in testcase: trinity version: trinity-x86_64-03f10b67-1_20210507 with following parameters: number: 99999 group: group-03 test-description: Trinity is a linux system call fuzz tester. test-url: http://codemonkey.org.uk/projects/trinity/ on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +---------------------------------------------+------------+------------+ | | ea7101d5d2 | 6243580a0d | +---------------------------------------------+------------+------------+ | boot_successes | 18 | 0 | | boot_failures | 0 | 19 | | BUG:kernel_NULL_pointer_dereference,address | 0 | 19 | | Oops:#[##] | 0 | 19 | | RIP:sync_blockdev_nowait | 0 | 19 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 19 | +---------------------------------------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot <oliver.sang(a)intel.com&gt; [ 10.022716] BUG: kernel NULL pointer dereference, address: 0000000000000028 [ 10.026733] #PF: supervisor read access in kernel mode [ 10.029727] #PF: error_code(0x0000) - not-present page [ 10.032785] PGD 0 P4D 0 [ 10.034379] Oops: 0000 [#1] SMP PTI [ 10.036642] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc4-00004-g6243580a0dc1 #1 [ 10.041104] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 [ 10.045800] RIP: 0010:sync_blockdev_nowait (kbuild/src/consumer/fs/block_dev.c:524) [ 10.048683] Code: 0f 1f 84 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 ff 74 03 31 c0 c3 <48> 8b 04 25 28 00 00 00 48 8b 78 30 e9 22 36 ed ff 66 66 2e 0f 1f All code ======== 0: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 7: 00 8: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) f: 00 00 00 00 13: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 1a: 00 00 00 1d: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 22: 48 85 ff test %rdi,%rdi 25: 74 03 je 0x2a 27: 31 c0 xor %eax,%eax 29: c3 retq 2a:* 48 8b 04 25 28 00 00 mov 0x28,%rax <-- trapping instruction 31: 00 32: 48 8b 78 30 mov 0x30(%rax),%rdi 36: e9 22 36 ed ff jmpq 0xffffffffffed365d 3b: 66 data16 3c: 66 data16 3d: 2e cs 3e: 0f .byte 0xf 3f: 1f (bad) Code starting with the faulting instruction =========================================== 0: 48 8b 04 25 28 00 00 mov 0x28,%rax 7: 00 8: 48 8b 78 30 mov 0x30(%rax),%rdi c: e9 22 36 ed ff jmpq 0xffffffffffed3633 11: 66 data16 12: 66 data16 13: 2e cs 14: 0f .byte 0xf 15: 1f (bad) [ 10.061540] RSP: 0018:ffffb0b740013e48 EFLAGS: 00010246 [ 10.064533] RAX: 0000000000000000 RBX: ffffa0e74d0aa800 RCX: 0000000000000000 [ 10.068509] RDX: 0000000000000002 RSI: 0000000000007b66 RDI: 0000000000000000 [ 10.072527] RBP: ffffffffa0c49e80 R08: ffffffffa20f6760 R09: 0000000000000000 [ 10.080566] R10: ffffffffa17fb8a0 R11: ffffa0e70cc02db0 R12: ffffa0e74d0aa800 [ 10.088688] R13: 0000000000000000 R14: ffffa0e70cb4f7d8 R15: 0000000000000000 [ 10.092408] FS: 0000000000000000(0000) GS:ffffa0ea2fd00000(0000) knlGS:0000000000000000 [ 10.097056] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 10.100508] CR2: 0000000000000028 CR3: 0000000421c0a000 CR4: 00000000000006e0 [ 10.104599] Call Trace: [ 10.108571] sync_filesystem (kbuild/src/consumer/fs/sync.c:56) [ 10.110976] generic_shutdown_super (kbuild/src/consumer/fs/super.c:449) [ 10.113773] kill_anon_super (kbuild/src/consumer/fs/super.c:1044 kbuild/src/consumer/fs/super.c:1058) [ 10.116046] proc_kill_sb (kbuild/src/consumer/fs/proc/root.c:276) [ 10.118231] deactivate_locked_super (kbuild/src/consumer/fs/super.c:342) [ 10.120925] cleanup_mnt (kbuild/src/consumer/fs/namespace.c:137 kbuild/src/consumer/fs/namespace.c:1137) [ 10.123031] mntput_no_expire (kbuild/src/consumer/fs/namespace.c:1222) [ 10.125440] ? rest_init (kbuild/src/consumer/init/main.c:1444) [ 10.127590] do_sysctl_args (kbuild/src/consumer/fs/proc/proc_sysctl.c:1862) [ 10.129635] kernel_init (kbuild/src/consumer/init/main.c:1469) [ 10.131622] ret_from_fork (kbuild/src/consumer/arch/x86/entry/entry_64.S:300) [ 10.133883] Modules linked in: [ 10.135878] CR2: 0000000000000028 [ 10.137634] ---[ end trace bd7aa22bcbea0ca1 ]--- [ 10.140417] RIP: 0010:sync_blockdev_nowait (kbuild/src/consumer/fs/block_dev.c:524) [ 10.143396] Code: 0f 1f 84 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 ff 74 03 31 c0 c3 <48> 8b 04 25 28 00 00 00 48 8b 78 30 e9 22 36 ed ff 66 66 2e 0f 1f All code ======== 0: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 7: 00 8: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) f: 00 00 00 00 13: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 1a: 00 00 00 1d: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 22: 48 85 ff test %rdi,%rdi 25: 74 03 je 0x2a 27: 31 c0 xor %eax,%eax 29: c3 retq 2a:* 48 8b 04 25 28 00 00 mov 0x28,%rax <-- trapping instruction 31: 00 32: 48 8b 78 30 mov 0x30(%rax),%rdi 36: e9 22 36 ed ff jmpq 0xffffffffffed365d 3b: 66 data16 3c: 66 data16 3d: 2e cs 3e: 0f .byte 0xf 3f: 1f (bad) Code starting with the faulting instruction =========================================== 0: 48 8b 04 25 28 00 00 mov 0x28,%rax 7: 00 8: 48 8b 78 30 mov 0x30(%rax),%rdi c: e9 22 36 ed ff jmpq 0xffffffffffed3633 11: 66 data16 12: 66 data16 13: 2e cs 14: 0f .byte 0xf 15: 1f (bad) To reproduce: # build kernel cd linux cp config-5.13.0-rc4-00004-g6243580a0dc1 .config make HOSTCC=gcc-9 CC=gcc-9 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email --- 0DAY/LKP+ Test Infrastructure Open Source Technology Center https://lists.01.org/hyperkitty/list/lkp@lists.01.org Intel Corporation Thanks, Oliver Sang