** Changed in: linux (Ubuntu) Status: Triaged => Invalid -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2020901
Title: io_uring regression in the Ubuntu kernel (deadlock) Status in linux package in Ubuntu: Invalid Status in linux source package in Kinetic: Won't Fix Bug description: Whenever using io_uring on the Ubuntu 5.15 or 5.19 kernel, one gets: ``` [ 123.226074] BUG: kernel NULL pointer dereference, address: 000000000000001d [ 123.226160] #PF: supervisor read access in kernel mode [ 123.226201] #PF: error_code(0x0000) - not-present page [ 123.226241] PGD 0 P4D 0 [ 123.226272] Oops: 0000 [#1] PREEMPT SMP PTI [ 123.226310] CPU: 2 PID: 4326 Comm: qemu-system-x86 Tainted: P O 5.19.0-42-generic #43~22.04.1-Ubuntu [ 123.226381] Hardware name: /D33217GKE, BIOS GKPPT10H.86A.0069.2019.1104.1340 11/04/2019 [ 123.228698] RIP: 0010:__blk_queue_split+0x53/0x1f0 [ 123.231029] Code: 00 00 83 f8 09 0f 84 e7 00 00 00 83 f8 03 0f 84 15 01 00 00 48 89 d1 4c 89 c6 4c 89 ca e8 b5 f2 ff ff 48 89 c3 48 85 db 74 5f <44> 8b 63 28 81 4b 10 00 40 00 00 49 be 00 00 00 00 00 00 00 80 4c [ 123.235909] RSP: 0018:ffff9bb3414779e8 EFLAGS: 00010286 [ 123.238328] RAX: fffffffffffffff5 RBX: fffffffffffffff5 RCX: 0000000000000000 [ 123.240737] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 123.243093] RBP: ffff9bb341477a08 R08: 0000000000000000 R09: 0000000000000000 [ 123.245435] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8e095d629ac0 [ 123.247735] R13: ffff9bb341477a18 R14: ffff8e0940df2040 R15: 0000000001400000 [ 123.250024] FS: 00007fa1cff602c0(0000) GS:ffff8e0a57300000(0000) knlGS:0000000000000000 [ 123.252306] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 123.254591] CR2: 000000000000001d CR3: 0000000111ccc006 CR4: 00000000001726e0 [ 123.256899] Call Trace: [ 123.259174] <TASK> [ 123.261406] blk_mq_submit_bio+0x8c/0x440 [ 123.263626] __submit_bio+0x109/0x1a0 [ 123.265795] __submit_bio_noacct+0x81/0x1f0 [ 123.267922] submit_bio_noacct_nocheck+0x91/0x120 [ 123.270016] ? blk_cgroup_bio_start+0xac/0x130 [ 123.272076] ? recalibrate_cpu_khz+0x10/0x10 [ 123.274114] ? ktime_get+0x46/0xc0 [ 123.276126] submit_bio_noacct+0x209/0x590 [ 123.278132] submit_bio+0x40/0xf0 [ 123.280121] __blkdev_direct_IO_async+0x146/0x1f0 [ 123.282108] blkdev_direct_IO.part.0+0x40/0xa0 [ 123.284097] blkdev_read_iter+0x9f/0x1a0 [ 123.286065] io_read+0xea/0x510 [ 123.288080] ? fget+0x83/0xc0 [ 123.290031] io_issue_sqe+0x61/0x440 [ 123.291960] ? io_init_req+0xfa/0x2f0 [ 123.293847] io_submit_sqes+0x141/0x4a0 [ 123.295703] ? __fget_light+0xb5/0x160 [ 123.297537] __do_sys_io_uring_enter+0x316/0x670 [ 123.299345] ? __secure_computing+0x9b/0x110 [ 123.301153] __x64_sys_io_uring_enter+0x22/0x40 [ 123.302900] do_syscall_64+0x5c/0x90 [ 123.304608] ? do_syscall_64+0x69/0x90 [ 123.306286] ? exit_to_user_mode_prepare+0x3b/0xd0 [ 123.307969] ? syscall_exit_to_user_mode+0x2a/0x50 [ 123.309605] ? do_syscall_64+0x69/0x90 [ 123.311176] ? do_syscall_64+0x69/0x90 [ 123.312717] ? sysvec_reschedule_ipi+0x7b/0x120 [ 123.314252] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 123.315791] RIP: 0033:0x7fa1d28855e1 [ 123.317314] Code: 89 55 e4 89 4d e0 4c 89 45 d8 4c 89 4d d0 44 8b 55 e0 4c 8b 45 d8 4c 8b 4d d0 b8 aa 01 00 00 8b 7d ec 8b 75 e8 8b 55 e4 0f 05 <48> 89 45 f8 48 8b 45 f8 5d c3 55 48 89 e5 48 83 ec 18 89 7d fc 89 [ 123.320664] RSP: 002b:00007fa17550ae68 EFLAGS: 00000216 ORIG_RAX: 00000000000001aa [ 123.322364] RAX: ffffffffffffffda RBX: 00005603c0418a28 RCX: 00007fa1d28855e1 [ 123.324060] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 000000000000002d [ 123.325684] RBP: 00007fa17550ae68 R08: 0000000000000000 R09: 0000000000000008 [ 123.327225] R10: 0000000000000000 R11: 0000000000000216 R12: 00005603c0418b10 [ 123.328734] R13: 00005603bdc48948 R14: 00005603bdc48988 R15: 0000000000000000 [ 123.330247] </TASK> [ 123.331740] Modules linked in: nft_masq nft_chain_nat zfs(PO) zunicode(PO) zzstd(O) zlua(O) zavl(PO) icp(PO) zcommon(PO) znvpair(PO) spl(O) ebtable_filter ebtables ip6table_raw ip6table_mangle ip6table_nat ip6table_filter ip6_tables iptable_raw iptable_mangle iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_filter bpfilter nf_tables nfnetlink vhost_vsock vmw_vsock_virtio_transport_common vhost vhost_iotlb vsock unix_diag tls bridge stp llc binfmt_misc intel_rapl_msr mei_pxp mei_hdcp intel_rapl_common x86_pkg_temp_thermal intel_powerclamp snd_hda_codec_hdmi coretemp snd_hda_intel kvm_intel snd_intel_dspcfg kvm snd_intel_sdw_acpi snd_hda_codec rapl intel_cstate snd_hda_core joydev snd_hwdep input_leds at24 mei_me snd_pcm snd_timer mei snd soundcore mac_hid sch_fq_codel dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua ramoops pstore_blk reed_solomon pstore_zone efi_pstore ip_tables x_tables autofs4 btrfs blake2b_generic raid10 raid456 async_raid6_recov async_ memcpy [ 123.331923] async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear i915 drm_buddy i2c_algo_bit ttm hid_generic drm_display_helper cec usbhid hid rc_core drm_kms_helper crct10dif_pclmul syscopyarea sysfillrect crc32_pclmul sysimgblt fb_sys_fops ghash_clmulni_intel cryptd ahci drm i2c_i801 e1000e i2c_smbus lpc_ich libahci video [ 123.350700] CR2: 000000000000001d [ 123.352644] ---[ end trace 0000000000000000 ]--- [ 123.354014] RIP: 0010:__blk_queue_split+0x53/0x1f0 [ 123.355051] Code: 00 00 83 f8 09 0f 84 e7 00 00 00 83 f8 03 0f 84 15 01 00 00 48 89 d1 4c 89 c6 4c 89 ca e8 b5 f2 ff ff 48 89 c3 48 85 db 74 5f <44> 8b 63 28 81 4b 10 00 40 00 00 49 be 00 00 00 00 00 00 00 80 4c [ 123.357377] RSP: 0018:ffff9bb3414779e8 EFLAGS: 00010286 [ 123.358553] RAX: fffffffffffffff5 RBX: fffffffffffffff5 RCX: 0000000000000000 [ 123.359798] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 123.361170] RBP: ffff9bb341477a08 R08: 0000000000000000 R09: 0000000000000000 [ 123.362410] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8e095d629ac0 [ 123.363544] R13: ffff9bb341477a18 R14: ffff8e0940df2040 R15: 0000000001400000 [ 123.364704] FS: 00007fa1cff602c0(0000) GS:ffff8e0a57300000(0000) knlGS:0000000000000000 [ 123.365949] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 123.367059] CR2: 000000000000001d CR3: 0000000111ccc006 CR4: 00000000001726e0 ``` This is due to a bad backport in the Ubuntu kernel: https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy/commit/?id=13f7058f1bd06c78775305cc0b16f0bcb0510eb6 As that can be triggered by an unprivileged user and causes a NULL pointer deref, this may be exploitable either as a way to DoS the system or even panic it in some cases. 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