FYI, we noticed the following commit (built with gcc-7): commit: 77f797eb8584e667eb32b5b7fbd39d8788938612 ("btrfs: Add a simple buffered iomap write") https://github.com/goldwynr/linux btrfs-iomap in testcase: xfstests with following parameters: disk: 4HDD fs: btrfs test: generic-group8 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: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 2G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +----------------------------------------------------------------------------------+------------+------------+ | | bf4c71f78d | 77f797eb85 | +----------------------------------------------------------------------------------+------------+------------+ | boot_successes | 33 | 3 | | boot_failures | 82 | 110 | | invoked_oom-killer:gfp_mask=0x | 2 | | | Mem-Info | 2 | | | BUG:kernel_reboot-without-warning_in_test_stage | 76 | 12 | | BUG:kernel_hang_in_boot_stage | 4 | 10 | | WARNING:at_fs/btrfs/extent-tree.c:#btrfs_free_reserved_data_space_noquota[btrfs] | 0 | 38 | | RIP:btrfs_free_reserved_data_space_noquota[btrfs] | 0 | 38 | | WARNING:at_fs/btrfs/inode.c:#btrfs_destroy_inode[btrfs] | 0 | 64 | | RIP:btrfs_destroy_inode[btrfs] | 0 | 64 | | WARNING:at_fs/btrfs/extent-tree.c:#btrfs_free_block_groups[btrfs] | 0 | 53 | | RIP:btrfs_free_block_groups[btrfs] | 0 | 53 | | kernel_BUG_at_fs/iomap.c | 0 | 44 | | invalid_opcode:#[##] | 0 | 44 | | RIP:iomap_write_begin | 0 | 44 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 44 | | WARNING:at_fs/btrfs/extent-tree.c:#update_bytes_may_use[btrfs] | 0 | 36 | | RIP:update_bytes_may_use[btrfs] | 0 | 36 | | BUG:kernel_hang_in_test_stage | 0 | 2 | | BUG:soft_lockup-CPU##stuck_for#s | 0 | 1 | | RIP:__memcpy | 0 | 1 | | Kernel_panic-not_syncing:softlockup:hung_tasks | 0 | 1 | +----------------------------------------------------------------------------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot <rong.a.chen(a)intel.com&gt; [ 36.938978] WARNING: CPU: 0 PID: 1946 at fs/btrfs/extent-tree.c:69 btrfs_free_reserved_data_space_noquota+0xf7/0x110 [btrfs] [ 36.944910] Modules linked in: btrfs xor zstd_decompress zstd_compress raid6_pq libcrc32c dm_mod crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel sr_mod cdrom sg ata_generic pata_acpi ppdev bochs_drm ttm snd_pcm aesni_intel snd_timer snd drm_kms_helper crypto_simd cryptd glue_helper joydev soundcore ata_piix pcspkr syscopyarea serio_raw sysfillrect libata sysimgblt fb_sys_fops i2c_piix4 drm parport_pc floppy parport ip_tables [ 36.960760] CPU: 0 PID: 1946 Comm: rm Not tainted 5.2.0-rc4-00004-g77f797e #1 [ 36.964087] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 36.967740] RIP: 0010:btrfs_free_reserved_data_space_noquota+0xf7/0x110 [btrfs] [ 36.971102] Code: ee e8 9d da bb c4 49 8b 04 24 48 85 c0 75 da 65 ff 0d a5 39 9d 3f e9 79 ff ff ff 48 89 c1 48 f7 d9 48 39 ca 0f 83 5e ff ff ff <0f> 0b 48 c7 43 28 00 00 00 00 e9 56 ff ff ff 66 2e 0f 1f 84 00 00 [ 36.978983] RSP: 0018:ffffb0f10316bcd8 EFLAGS: 00010287 [ 36.981856] RAX: fffffffffffff000 RBX: ffff8ff0cf4f7400 RCX: 0000000000001000 [ 36.985231] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8ff0cf4f7400 [ 36.988659] RBP: 0000000000000fff R08: 0000000000004000 R09: ffff8ff0fc6a0000 [ 36.994422] R10: ffff8ff0d04a9000 R11: 0000000000000001 R12: ffff8ff0eb0f9e60 [ 36.997846] R13: ffff8ff0fc6a0000 R14: ffff8ff0d04a9000 R15: ffffb0f10316bdd4 [ 37.001278] FS: 00007faf9844c480(0000) GS:ffff8ff0eb000000(0000) knlGS:0000000000000000 [ 37.004933] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 37.007912] CR2: 0000555b176921f8 CR3: 000000005b266000 CR4: 00000000000406f0 [ 37.011332] Call Trace: [ 37.013405] btrfs_clear_delalloc_extent+0x1a1/0x420 [btrfs] [ 37.016327] ? _cond_resched+0x19/0x30 [ 37.018764] clear_state_bit+0x75/0x1b0 [btrfs] [ 37.021409] __clear_extent_bit+0x222/0x440 [btrfs] [ 37.024117] ? _cond_resched+0x19/0x30 [ 37.026529] clear_extent_bit+0x15/0x20 [btrfs] [ 37.029122] btrfs_evict_inode+0x152/0x4c0 [btrfs] [ 37.031692] evict+0xd9/0x1b0 [ 37.033758] do_unlinkat+0x1ab/0x320 [ 37.035979] do_syscall_64+0x5b/0x1e0 [ 37.038263] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 37.040914] RIP: 0033:0x7faf97f6e117 [ 37.043118] Code: 73 01 c3 48 8b 0d 81 bd 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 07 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 bd 2b 00 f7 d8 64 89 01 48 [ 37.051009] RSP: 002b:00007ffd09883228 EFLAGS: 00000206 ORIG_RAX: 0000000000000107 [ 37.054494] RAX: ffffffffffffffda RBX: 0000555b17692320 RCX: 00007faf97f6e117 [ 37.057846] RDX: 0000000000000000 RSI: 0000555b176910f0 RDI: 00000000ffffff9c [ 37.061279] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 37.064611] R10: 000000000000015d R11: 0000000000000206 R12: 0000555b17691060 [ 37.068040] R13: 00007ffd09883360 R14: 0000555b17692320 R15: 0000000000000000 [ 37.071513] ---[ end trace 35d42372724e81c8 ]--- To reproduce: # build kernel cd linux cp config-5.2.0-rc4-00004-g77f797e .config make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 prepare make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 modules_prepare make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 SHELL=/bin/bash make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 bzImage 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 <bzImage> -m modules.cgz job-script # job-script is attached in this email Thanks, Rong Chen