Managed to break sysfs when running:
sudo ./stress-ng --sysfs 4 -t 60 -v --verify
Kernel: 4.15.0-29-generic and 4.17 too, this seems to occur on previous 4.15 kernels but I've not tested too far back.
[ 45.057702] ------------[ cut here ]------------
[ 45.057704] kernel BUG at /build/linux-4OqUyO/linux-4.15.0/drivers/block/virtio_blk.c:565!
[ 45.057773] illegal operation: 0001 ilc:1 [#1] SMP
[ 45.057775] Modules linked in: binfmt_misc zfs(PO) zunicode(PO) zavl(PO) icp(PO) isofs zcommon(PO) znvpair(PO) spl(O) ghash_s390 prng aes_s390 des_s390 des_generic sha512_s390 sha256_s390 sha1_s390 sha_common vfio_ccw vfio_mdev mdev vfio_iommu_type1 vfio sch_fq_codel ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi nfsd auth_rpcgss nfs_acl lockd grace scsi_transport_iscsi sunrpc ip_tables x_tables btrfs zstd_compress zlib_deflate raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 linear crc32_vx_s390 virtio_net virtio_blk
[ 45.057805] CPU: 0 PID: 5056 Comm: stress-ng-sysfs Tainted: P O 4.15.0-29-generic #31-Ubuntu
[ 45.057806] Hardware name: IBM 2964 N63 400 (KVM/Linux)
[ 45.057809] Krnl PSW : 000000002a20609d 00000000800ebb38 (virtblk_cache_type_show+0x82/0x88 [virtio_blk])
[ 45.057814] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
[ 45.057816] Krnl GPRS: de6dc5c2778317a7 000000007ff93a20 0000000000000080 0000000000001164
[ 45.057818] 000003ff800058da 0000000000001165 000000006b9cc840 000000007061a100
[ 45.057819] 0000000000000000 000000000068feb8 0000000072c30d80 0000000071972000
[ 45.057821] 000003ff80008210 0000000000001000 000003ff800058da 0000000070a47ce8
[ 45.057830] Krnl Code: 000003ff80005912: ebbff0a80004 lmg %r11,%r15,168(%r15)
000003ff80005918: c0f400000560 brcl 15,3ff800063d8
#000003ff8000591e: a7f40001 brc 15,3ff80005920
>000003ff80005922: 0707 bcr 0,%r7
000003ff80005924: 0707 bcr 0,%r7
000003ff80005926: 0707 bcr 0,%r7
000003ff80005928: c00400000000 brcl 0,3ff80005928
000003ff8000592e: eb6ff0480024 stmg %r6,%r15,72(%r15)
[ 45.057844] Call Trace:
[ 45.057847] ([<000003ff800058da>] virtblk_cache_type_show+0x3a/0x88 [virtio_blk])
[ 45.057852] [<000000000068fef4>] dev_attr_show+0x3c/0x80
[ 45.057858] [<0000000000424414>] sysfs_kf_seq_show+0xbc/0x1a8
[ 45.057862] [<00000000003afddc>] seq_read+0xec/0x4c8
[ 45.057865] [<0000000000381bba>] vfs_read+0x8a/0x150
[ 45.057867] [<0000000000382156>] SyS_read+0x66/0xe0
[ 45.057872] [<00000000008e2350>] system_call+0xdc/0x2c8
[ 45.057873] Last Breaking-Event-Address:
[ 45.057875] [<000003ff8000591e>] virtblk_cache_type_show+0x7e/0x88 [virtio_blk]
[ 45.057876]
[ 45.057877] ---[ end trace 49fd8401e53e0e99 ]---
This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1782565
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.