Greeting, FYI, we noticed the following commit (built with gcc-9): commit: 98c6e236168b29be199f59d8b1d06522fd8b01f4 ("char_dev: replace cdev_map with an xarray") git://git.infradead.org/users/hch/block.git gendisk-lookup in testcase: xfstests version: xfstests-x86_64-bbfab0d-1_20200821 with following parameters: disk: 4HDD fs: ext4 test: generic-group00 ucode: 0x28 test-description: xfstests is a regression test suite for xfs and other files ystems. test-url: git://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git on test machine: 8 threads Intel(R) Core(TM) i7-4790 v3 @ 3.60GHz with 6G memory caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): If you fix the issue, kindly add following tag Reported-by: kernel test robot <rong.a.chen(a)intel.com&gt; [ 177.153697] run fstests generic/475 at 2020-08-31 05:28:54 [ 185.493470] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: acl,user_xattr [ 185.513734] EXT4-fs error (device dm-0): ext4_read_inode_bitmap:199: comm fsstress: Cannot read inode bitmap - block_group = 0, inode_bitmap = 1079 [ 185.515318] Buffer I/O error on dev dm-0, logical block 78643184, async page read [ 185.528294] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 185.544461] EXT4-fs (dm-0): I/O error while writing superblock [ 185.551022] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:215: comm fsstress: Error while async write back metadata [ 185.563842] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 185.571860] EXT4-fs (dm-0): I/O error while writing superblock [ 185.578394] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:215: comm fsstress: Error while async write back metadata [ 185.591169] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 185.599183] EXT4-fs (dm-0): I/O error while writing superblock [ 185.605769] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:215: comm fsstress: Error while async write back metadata [ 185.618572] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 185.626614] EXT4-fs (dm-0): I/O error while writing superblock [ 185.633200] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:215: comm fsstress: Error while async write back metadata [ 185.646060] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 185.654090] EXT4-fs (dm-0): I/O error while writing superblock [ 185.660659] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:215: comm fsstress: Error while async write back metadata [ 185.673522] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 185.681555] EXT4-fs (dm-0): I/O error while writing superblock [ 185.688129] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:215: comm fsstress: Error while async write back metadata [ 185.701033] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 185.709092] EXT4-fs (dm-0): I/O error while writing superblock [ 185.715685] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:215: comm fsstress: Error while async write back metadata [ 185.728677] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 185.736797] EXT4-fs (dm-0): I/O error while writing superblock [ 185.743413] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:215: comm fsstress: Error while async write back metadata [ 185.756386] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 185.764475] EXT4-fs (dm-0): I/O error while writing superblock [ 185.771129] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:215: comm fsstress: Error while async write back metadata [ 185.784183] EXT4-fs (dm-0): I/O error while writing superblock [ 185.795337] JBD2: Error -5 detected when updating journal superblock for dm-0-8. [ 185.803526] Aborting journal on device dm-0-8. [ 185.808804] JBD2: Error -5 detected when updating journal superblock for dm-0-8. [ 185.893447] EXT4-fs (dm-0): recovery complete [ 185.898646] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: acl,user_xattr [ 186.927928] Aborting journal on device dm-0-8. [ 186.933514] EXT4-fs error (device dm-0) in __ext4_new_inode:946: Journal has aborted [ 186.933531] JBD2: Error -5 detected when updating journal superblock for dm-0-8. [ 186.942139] EXT4-fs (dm-0): I/O error while writing superblock [ 187.009454] EXT4-fs (dm-0): I/O error while writing superblock [ 187.016110] EXT4-fs error (device dm-0): ext4_journal_check_start:83: Detected aborted journal [ 187.025515] EXT4-fs (dm-0): Remounting filesystem read-only [ 187.031933] EXT4-fs (dm-0): ext4_writepages: jbd2_start: 9223372036854775807 pages, ino 16777218; err -30 [ 187.234910] EXT4-fs (dm-0): 2 truncates cleaned up [ 187.240541] EXT4-fs (dm-0): recovery complete [ 187.306615] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: acl,user_xattr [ 188.378793] Aborting journal on device dm-0-8. [ 188.384169] JBD2: Error -5 detected when updating journal superblock for dm-0-8. [ 191.575574] buffer_io_error: 10 callbacks suppressed [ 191.575576] Buffer I/O error on dev dm-0, logical block 0, lost sync page write [ 191.591358] EXT4-fs (dm-0): I/O error while writing superblock [ 191.598420] EXT4-fs error (device dm-0): ext4_journal_check_start:83: Detected aborted journal [ 191.608271] EXT4-fs (dm-0): Remounting filesystem read-only [ 198.613314] killall invoked oom-killer: gfp_mask=0x40cd0(GFP_KERNEL|__GFP_COMP|__GFP_RECLAIMABLE), order=0, oom_score_adj=250 [ 198.625844] CPU: 7 PID: 8712 Comm: killall Not tainted 5.9.0-rc2-00097-g98c6e236168b2 #1 [ 198.635112] Hardware name: Dell Inc. OptiPlex 9020/03CPWF, BIOS A11 04/01/2015 [ 198.643507] Call Trace: [ 198.647155] dump_stack+0x57/0x80 [ 198.651640] dump_header+0x4a/0x1fe [ 198.656270] oom_kill_process.cold+0xb/0x10 [ 198.661568] out_of_memory+0x1d8/0x460 [ 198.667035] out_of_memory+0x67/0xe0 [ 198.671739] __alloc_pages_slowpath+0xcf2/0xde0 [ 198.678380] __alloc_pages_nodemask+0x2fb/0x360 [ 198.683948] allocate_slab+0x319/0x440 [ 198.688731] ___slab_alloc+0x380/0x5e0 [ 198.693498] ? proc_alloc_inode+0x16/0x80 [ 198.698511] ? __memcg_kmem_charge+0x76/0xc0 [ 198.703745] ? __mod_memcg_lruvec_state+0x1f/0xe0 [ 198.709455] ? proc_alloc_inode+0x16/0x80 [ 198.714483] __slab_alloc+0xe/0x20 [ 198.718890] kmem_cache_alloc+0x422/0x480 [ 198.723863] proc_alloc_inode+0x16/0x80 [ 198.728637] alloc_inode+0x1d/0xa0 [ 198.732981] new_inode_pseudo+0xd/0x60 [ 198.737658] new_inode+0x13/0x40 [ 198.741775] proc_pid_make_inode+0x1c/0x120 [ 198.746853] proc_pid_instantiate+0x1e/0xa0 [ 198.751935] proc_pid_lookup+0x83/0x120 [ 198.756611] proc_root_lookup+0x1d/0x40 [ 198.761283] __lookup_slow+0x84/0x160 [ 198.765759] walk_component+0x13b/0x1c0 [ 198.770406] link_path_walk+0x220/0x360 [ 198.775554] ? path_init+0x323/0x3c0 [ 198.779640] path_openat+0xca/0x10a0 [ 198.783978] ? seq_puts+0x39/0x60 [ 198.787941] do_filp_open+0x91/0x100 [ 198.792216] ? list_lru_add+0x13b/0x160 [ 198.796483] ? __check_object_size+0x136/0x147 [ 198.801348] do_sys_openat2+0x20d/0x2e0 [ 198.805621] do_sys_open+0x44/0x80 [ 198.809426] do_syscall_64+0x33/0x40 [ 198.813404] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 198.818880] RIP: 0033:0x7fc6191311ae [ 198.822872] Code: 25 00 00 41 00 3d 00 00 41 00 74 48 48 8d 05 59 65 0d 00 8b 00 85 c0 75 69 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 0f 87 a6 00 00 00 48 8b 4c 24 28 64 48 33 0c 25 [ 198.842436] RSP: 002b:00007ffcc6eec1a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 [ 198.850408] RAX: ffffffffffffffda RBX: 000055994681c260 RCX: 00007fc6191311ae [ 198.857969] RDX: 0000000000000000 RSI: 000055994681eaa0 RDI: 00000000ffffff9c [ 198.865500] RBP: 0000000000000008 R08: 0000000000000008 R09: 0000000000000001 [ 198.873044] R10: 0000000000000000 R11: 0000000000000246 R12: 000055994542523a [ 198.880565] R13: 000055994542523a R14: 0000000000000001 R15: 0000000000000000 [ 198.888092] Mem-Info: [ 198.890774] active_anon:597 inactive_anon:110468 isolated_anon:49 [ 198.890774] active_file:144 inactive_file:0 isolated_file:50 [ 198.890774] unevictable:261148 dirty:4 writeback:0 [ 198.890774] slab_reclaimable:17116 slab_unreclaimable:1063669 [ 198.890774] mapped:5838 shmem:4299 pagetables:3025 bounce:0 [ 198.890774] free:23685 free_pcp:1181 free_cma:3668 To reproduce: # build kernel cd linux cp config-5.9.0-rc3-00002-gb4ad8182a9a6ca .config make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 olddefconfig prepare modules_prepare bzImage modules make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 INSTALL_MOD_PATH=<mod-install-dir> modules_install cd <mod-install-dir> find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email Thanks, Rong Chen