FYI, we noticed the following commit (built with gcc-7): commit: d95576ef1d8eaf8cf481c8f8e70efa324778e6d7 ("[RFC PATCH v2 4/9] md:raid1: rd_hint support and consider stacked layer case") url: https://github.com/0day-ci/linux/commits/Bob-Liu/Block-XFS-Support-alternative-mirror-device-retry/20190214-025648 base: https://git.kernel.org/cgit/fs/xfs/xfs-linux.git for-next in testcase: mdadm-selftests with following parameters: disk: 1HDD test_prefix: 05 on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 4G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +------------------------------------------+------------+------------+ | | d539a2b995 | d95576ef1d | +------------------------------------------+------------+------------+ | boot_successes | 4 | 0 | | boot_failures | 0 | 4 | | BUG:unable_to_handle_kernel | 0 | 4 | | Oops:#[##] | 0 | 4 | | RIP:raid#_read_request[raid#] | 0 | 4 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 4 | +------------------------------------------+------------+------------+ [ 209.214500] BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 [ 209.216788] #PF error: [normal kernel read fault] [ 209.218085] PGD 0 P4D 0 [ 209.218958] Oops: 0000 [#1] SMP PTI [ 209.221021] CPU: 1 PID: 4707 Comm: mkfs.ext3 Not tainted 5.0.0-rc5-00007-gd95576e #1 [ 209.225082] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 209.230389] RIP: 0010:raid1_read_request+0x593/0xb60 [raid1] [ 209.232847] Code: 00 00 49 83 ed 20 48 89 2c 24 45 31 e4 4c 89 fd 4d 89 ef 49 89 d5 eb 12 48 8b 45 08 4e 8b 34 38 49 83 ef 20 41 39 5d 30 74 25 <49> 8b 46 30 83 eb 01 48 8b 80 80 00 00 00 48 8b b8 18 04 00 00 e8 [ 209.249396] RSP: 0018:ffffc9000366b958 EFLAGS: 00010297 [ 209.251741] RAX: ffff88807dd223c0 RBX: 0000000000000001 RCX: 0000000000000017 [ 209.255548] RDX: ffff88807aa51300 RSI: ffff88807dce0800 RDI: ffff88807f95d8b0 [ 209.258228] RBP: ffff8880a9909400 R08: 000000384a35c379 R09: 00000000ffffffff [ 209.262076] R10: 0000000000000000 R11: 0000000000000008 R12: 0000000000000001 [ 209.265889] R13: ffff88807aa51300 R14: 0000000000000000 R15: 0000000000000000 [ 209.269677] FS: 00007f09a63e6bc0(0000) GS:ffff88813fd00000(0000) knlGS:0000000000000000 [ 209.273869] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 209.277390] CR2: 0000000000000030 CR3: 0000000078ba2000 CR4: 00000000000406e0 [ 209.280092] Call Trace: [ 209.281930] ? __switch_to_asm+0x40/0x70 [ 209.283974] ? select_task_rq_fair+0x315/0xe50 [ 209.286121] ? md_bitmap_checkpage+0x90/0x120 [ 209.289308] ? finish_wait+0x80/0x80 [ 209.291306] raid1_make_request+0x67/0x80 [raid1] [ 209.293514] md_handle_request+0x139/0x1b0 [ 209.297291] md_make_request+0x75/0x1a0 [ 209.299368] generic_make_request+0x1d0/0x420 [ 209.301549] ? submit_bio+0x6c/0x140 [ 209.303597] submit_bio+0x6c/0x140 [ 209.305595] ? guard_bio_eod+0x39/0x120 [ 209.307650] submit_bh_wbc+0x16d/0x190 [ 209.309686] ? __end_buffer_read_notouch+0x20/0x20 [ 209.311918] ? mark_buffer_write_io_error+0x60/0x60 [ 209.314158] ll_rw_block+0xaf/0xc0 [ 209.316130] __block_write_begin_int+0x43f/0x5f0 [ 209.319376] ? check_disk_change+0x60/0x60 [ 209.321518] ? io_schedule_timeout+0x1e/0x50 [ 209.323677] ? check_disk_change+0x60/0x60 [ 209.325817] block_write_begin+0x44/0xe0 [ 209.327928] generic_perform_write+0xb6/0x1d0 [ 209.330114] __generic_file_write_iter+0x192/0x1c0 [ 209.333366] blkdev_write_iter+0xa8/0x130 [ 209.335371] ? __vfs_write+0x128/0x1b0 [ 209.337368] __vfs_write+0x128/0x1b0 [ 209.339368] vfs_write+0xbe/0x1b0 [ 209.341327] ksys_pwrite64+0x71/0x90 [ 209.343336] do_syscall_64+0x5b/0x180 [ 209.345371] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 209.348683] RIP: 0033:0x7f09a525cd03 [ 209.350733] Code: f0 ff ff 73 01 c3 48 8b 0d 92 f1 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 83 3d 09 4a 2c 00 00 75 13 49 89 ca b8 12 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 ab b5 01 00 48 89 04 24 [ 209.359133] RSP: 002b:00007ffe827af7d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 [ 209.362121] RAX: ffffffffffffffda RBX: 0000000000000c00 RCX: 00007f09a525cd03 [ 209.365811] RDX: 0000000000000c00 RSI: 000055a3a4bd2220 RDI: 0000000000000004 [ 209.370477] RBP: 000055a3a4bd2220 R08: 0000000000000400 R09: 0000000000000210 [ 209.373145] R10: 0000000000000400 R11: 0000000000000246 R12: 000055a3a4bccff0 [ 209.375881] R13: 000055a3a4bccd50 R14: 000055a3a4bccd50 R15: 0000000000000000 [ 209.380619] Modules linked in: multipath loop raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid10 raid1 raid0 sr_mod cdrom sg crct10dif_pclmul crc32_pclmul ata_generic pata_acpi crc32c_intel ghash_clmulni_intel ppdev aesni_intel crypto_simd cryptd glue_helper snd_pcm snd_timer snd soundcore pcspkr serio_raw ata_piix libata i2c_piix4 parport_pc floppy parport ip_tables [ 209.395776] CR2: 0000000000000030 [ 209.407973] ---[ end trace 862ccb76d560c07b ]--- To reproduce: git clone https://github.com/intel/lkp-tests.git cd lkp-tests find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz bin/lkp qemu -k -m modules.cgz job-script # job-script is attached in this email Thanks, lkp