ubuntu_stress_smoke_test:dev BUG: kernel NULL pointer dereference

[Francis Ginther]

Issue found with focal linux 5.4.0-74.83 on system blanka during cycle sru-20210510.

This is the first of several BUGs. May be similar to lp:1929187.

[ 380.716900] sr 0:0:0:0: [sr0] CDROM not ready. Make sure there is a disc in the drive.
[ 382.023370] ZFS: Loaded module v0.8.3-1ubuntu12.7, ZFS pool version 5000, ZFS filesystem version 5
[ 382.489788] BUG: kernel NULL pointer dereference, address: 0000000000000010
[ 382.497560] #PF: supervisor read access in kernel mode
[ 382.503291] #PF: error_code(0x0000) - not-present page
[ 382.509022] PGD 0 P4D 0
[ 382.511847] Oops: 0000 [#1] SMP NOPTI
[ 382.515932] CPU: 130 PID: 126477 Comm: stress-ng Tainted: P OE 5.4.0-74-generic #83-Ubuntu
[ 382.526511] Hardware name: NVIDIA DGXA100 920-23687-2530-000/DGXA100, BIOS 0.34 02/08/2021
[ 382.535740] RIP: 0010:knem_miscdev_poll+0x16/0x50 [knem]
[ 382.541669] Code: Bad RIP value.
[ 382.545267] RSP: 0018:ffffb952eeaf7ab8 EFLAGS: 00010282
[ 382.551095] RAX: 0000000000000008 RBX: 0000000000000000 RCX: ffff99a2b6923801
[ 382.559056] RDX: 0000000000000001 RSI: ffffb952eeaf7c40 RDI: ffff99a2b6923800
[ 382.567015] RBP: ffffb952eeaf7ac0 R08: ffff99a2b6923800 R09: 0000000000000016
[ 382.574976] R10: ffff99a61b914fc0 R11: 0000000000000000 R12: 0000000000000019
[ 382.582934] R13: 0000000000000000 R14: 0000000000000000 R15: ffffb952eeaf7b4c
[ 382.590895] FS: 00007fc1069ab380(0000) GS:ffff99aacdc80000(0000) knlGS:0000000000000000
[ 382.599923] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 382.606331] CR2: ffffffffc04efffc CR3: 00000074e9be2000 CR4: 0000000000340ee0
[ 382.614291] Call Trace:
[ 382.617025] do_sys_poll+0x2ad/0x520
[ 382.621017] ? __radix_tree_delete+0x8f/0xf0
[ 382.625780] ? radix_tree_delete_item+0x6a/0xd0
[ 382.630836] ? put_pid+0x50/0x50
[ 382.634439] ? misc_open+0x12d/0x160
[ 382.638429] ? chrdev_open+0xd3/0x1c0
[ 382.642515] ? ima_file_check+0x5a/0x80
[ 382.646793] ? do_last+0x1a3/0x900
[ 382.650586] ? mntput+0x24/0x40
[ 382.654089] ? terminate_walk+0x7f/0xf0
[ 382.658368] ? path_openat+0xc6/0x290
[ 382.662455] ? _copy_to_user+0x2c/0x30
[ 382.666626] ? cp_new_stat+0x152/0x180
[ 382.670805] ? do_vfs_ioctl+0x407/0x670
[ 382.675084] ? __do_sys_newfstat+0x61/0x70
[ 382.679655] ? __fget_light+0x57/0x70
[ 382.683739] __x64_sys_poll+0xa5/0x150
[ 382.687923] do_syscall_64+0x57/0x190
[ 382.692001] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 382.697636] RIP: 0033:0x7fc106ae4aff
[ 382.701622] Code: 54 24 1c 48 89 74 24 10 48 89 7c 24 08 e8 79 1c f8 ff 8b 54 24 1c 48 8b 74 24 10 41 89 c0 48 8b 7c 24 08 b8 07 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2b 44 89 c7 89 44 24 08 e8 ad 1c f8 ff 8b 44
[ 382.722576] RSP: 002b:00007ffe29899670 EFLAGS: 00000293 ORIG_RAX: 0000000000000007
[ 382.731023] RAX: ffffffffffffffda RBX: 0000000000000010 RCX: 00007fc106ae4aff
[ 382.738983] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007ffe29899718
[ 382.746943] RBP: 00007ffe29899930 R08: 0000000000000000 R09: 00007ffe29899648
[ 382.754904] R10: 00007ffe29899640 R11: 0000000000000293 R12: 0000000000000016
[ 382.762863] R13: 00007ffe2989dc50 R14: 00007ffe298997a0 R15: 0000000000000001
[ 382.770825] Modules linked in: cuse zfs(PO) zunicode(PO) zlua(PO) zavl(PO) icp(PO) zcommon(PO) znvpair(PO) spl(O) snd_seq snd_seq_device snd_timer snd soundcore dccp_ipv4 dccp atm algif_rng aegis128 aegis128_aesni algif_aead anubis fcrypt khazad seed sm4_generic tea ccm cmac md4 michael_mic nhpoly1305_avx2 nhpoly1305_sse2 nhpoly1305 poly1305_x86_64 poly1305_generic rmd128 rmd160 rmd256 rmd320 sha3_generic sm3_generic streebog_generic tgr192 wp512 xxhash_generic algif_hash blowfish_generic blowfish_x86_64 blowfish_common cast5_avx_x86_64 cast5_generic des_generic des3_ede_x86_64 libdes salsa20_generic chacha_x86_64 chacha_generic camellia_generic camellia_aesni_avx2 camellia_aesni_avx_x86_64 camellia_x86_64 cast6_avx_x86_64 cast6_generic cast_common serpent_avx2 serpent_avx_x86_64 serpent_sse2_x86_64 serpent_generic twofish_generic twofish_avx_x86_64 twofish_x86_64_3way twofish_x86_64 twofish_common algif_skcipher af_alg nls_iso8859_1 dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua
[ 382.770869] ipmi_ssif amd64_edac_mod edac_mce_amd kvm_amd kvm input_leds cdc_ether usbnet mii ccp k10temp ipmi_si ipmi_devintf ipmi_msghandler mac_hid sch_fq_codel knem(OE) ip_tables x_tables autofs4 btrfs zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear ses enclosure ast drm_vram_helper ttm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel mlx5_core(OE) pci_hyperv_intf aesni_intel drm_kms_helper crypto_simd syscopyarea cryptd sysfillrect sysimgblt glue_helper tls fb_sys_fops hid_generic mlxfw(OE) igb mpt3sas uas dca mdev(OE) usbhid nvme raid_class i2c_algo_bit mlx_compat(OE) scsi_transport_sas hid usb_storage drm nvme_core i2c_piix4
[ 382.939741] CR2: 0000000000000010
[ 382.943437] ---[ end trace 6a64b973355e503e ]---

[dann frazier (dannf)]

The crash here is in a module provided by the Mellanox OFED stack (knem), and is not reproducible w/o it, so I think this bug is Invalid with respect to the generic Ubuntu kernel.