ubuntu-host driver lacks lseek ops

Bug #1934110 reported by Colin Ian King
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
High
Colin Ian King
Groovy
High
Unassigned
Hirsute
High
Unassigned

Bug Description

[ SRU Justification ][GROOVY][HIRSUTE][IMPISH]

== Impact ==

The ubuntu-host driver lacks procfs lseek ops and lseeking on the procfs esm-token file will jump to a NULL address causing the following splat:

  942.470568] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 942.471157] #PF: supervisor instruction fetch in kernel mode
[ 942.471724] #PF: error_code(0x0010) - not-present page
[ 942.472297] PGD 0 P4D 0
[ 942.472867] Oops: 0010 [#1] SMP PTI
[ 942.473435] CPU: 2 PID: 5661 Comm: stress-ng Not tainted 5.13.0-9-generic #9
[ 942.474012] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[ 942.474599] RIP: 0010:0x0
[ 942.475194] Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
[ 942.475792] RSP: 0018:ffffaacf80ff7eb8 EFLAGS: 00010246
[ 942.476383] RAX: 0000000000000000 RBX: ffff9eaa8a175240 RCX: 0000000000000001
[ 942.476986] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9eaa838d5800
[ 942.477600] RBP: ffffaacf80ff7ed0 R08: 0000000000004000 R09: 0000000000000004
[ 942.478203] R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000
[ 942.478800] R13: 0000000000000000 R14: ffffffffffffffea R15: ffff9eaa838d5800
[ 942.479399] FS: 00007f998d487f00(0000) GS:ffff9eaaffc80000(0000) knlGS:0000000000000000
[ 942.480006] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 942.480607] CR2: ffffffffffffffd6 CR3: 000000010a774002 CR4: 0000000000370ee0
[ 942.481219] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 942.481855] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 942.482458] Call Trace:
[ 942.483052] proc_reg_llseek+0x4e/0x80
[ 942.483646] ? __fdget_pos+0x43/0x50
[ 942.484234] ksys_lseek+0x84/0xc0
[ 942.484815] __x64_sys_lseek+0x1a/0x20
[ 942.485412] do_syscall_64+0x61/0xb0
[ 942.485966] ? asm_exc_page_fault+0x8/0x30
[ 942.486476] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 942.486994] RIP: 0033:0x7f998d5c1cdb
[ 942.487512] Code: ff ff c3 0f 1f 40 00 48 8b 15 89 81 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb ba 0f 1f 00 f3 0f 1e fa b8 08 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 59 81 0d 00 f7 d8
[ 942.488593] RSP: 002b:00007ffdf61c5328 EFLAGS: 00000246 ORIG_RAX: 0000000000000008
[ 942.489148] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f998d5c1cdb
[ 942.489710] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
[ 942.490252] RBP: 0000000000000004 R08: 000001785e4740dd R09: 0000562dbebb9e50
[ 942.490801] R10: 00007ffdf61c5300 R11: 0000000000000246 R12: 00007ffdf61c63f0
[ 942.491354] R13: 00007ffdf61c53f0 R14: 0000000000000003 R15: 00000000000001e9

== Fix ==

Add the default_llseek ops:

diff --git a/ubuntu/ubuntu-host/ubuntu-host.c b/ubuntu/ubuntu-host/ubuntu-host.c
index 1abd402..a4c0636 100644
--- a/ubuntu/ubuntu-host/ubuntu-host.c
+++ b/ubuntu/ubuntu-host/ubuntu-host.c
@@ -38,6 +38,8 @@ static ssize_t esm_token_write(struct file *f, const char __user *buf,
 static const struct proc_ops esm_token_fops = {
        .proc_read = esm_token_read,
        .proc_write = esm_token_write,
+ .proc_lseek = default_llseek,
+
 };

== Test plan ==

modrobe ubuntu-host
stress-ng --procfs 0 -t 60

without the fix we hit the splat. With the fix it's OK.

== Where problems could occur ==

This one liner adds the missing proc_lseek op. It is hard to see where it can cause a regression since it affects the driver no other way. I doubt any code is relying on the current semantics of lseek not working.

Changed in linux (Ubuntu):
status: New → In Progress
importance: Undecided → High
assignee: nobody → Colin Ian King (colin-king)
description: updated
Stefan Bader (smb)
Changed in linux (Ubuntu Groovy):
importance: Undecided → High
status: New → In Progress
Changed in linux (Ubuntu Hirsute):
importance: Undecided → High
status: New → In Progress
Changed in linux (Ubuntu Groovy):
status: In Progress → Fix Committed
Changed in linux (Ubuntu Hirsute):
status: In Progress → Fix Committed
Revision history for this message
Ubuntu Kernel Bot (ubuntu-kernel-bot) wrote :

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-hirsute' to 'verification-done-hirsute'. If the problem still exists, change the tag 'verification-needed-hirsute' to 'verification-failed-hirsute'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

tags: added: verification-needed-hirsute
Revision history for this message
Ubuntu Kernel Bot (ubuntu-kernel-bot) wrote :

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

tags: added: verification-needed-focal
Revision history for this message
Brian Murray (brian-murray) wrote :

The Groovy Gorilla has reached end of life, so this bug will not be fixed for that release

Changed in linux (Ubuntu Groovy):
status: Fix Committed → Won't Fix
Revision history for this message
Colin Ian King (colin-king) wrote :

Tested on Hirsute 5.11.0-26-generic, no crash observed, marking as verified.

tags: added: verification-done-hirsute
removed: verification-needed-hirsute
Revision history for this message
Colin Ian King (colin-king) wrote :

Removing focal tag as this SRU does not apply to focal, it does not have this driver.

tags: removed: verification-needed-focal
Revision history for this message
Launchpad Janitor (janitor) wrote :
Download full text (48.1 KiB)

This bug was fixed in the package linux - 5.11.0-31.33

---------------
linux (5.11.0-31.33) hirsute; urgency=medium

  * hirsute/linux: 5.11.0-31.33 -proposed tracker (LP: #1939553)

  * REGRESSION: shiftfs lets sendfile fail with EINVAL (LP: #1939301)
    - SAUCE: shiftfs: fix sendfile() invocations

linux (5.11.0-26.28) hirsute; urgency=medium

  * Packaging resync (LP: #1786013)
    - update dkms package versions

  * large_dir in ext4 broken (LP: #1933074)
    - SAUCE: ext4: fix directory index node split corruption

  * Add l2tp.sh in net from ubuntu_kernel_selftests back (LP: #1934293)
    - Revert "UBUNTU: SAUCE: selftests/net -- disable l2tp.sh test"

  * icmp_redirect.sh in net from ubuntu_kernel_selftests failed on F-OEM-5.6 /
    F-OEM-5.10 / F-OEM-5.13 / F / G / H (LP: #1880645)
    - selftests: icmp_redirect: support expected failures

  * Mute/mic LEDs no function on some HP platfroms (LP: #1934878)
    - ALSA: hda/realtek: fix mute/micmute LEDs for HP ProBook 450 G8
    - ALSA: hda/realtek: fix mute/micmute LEDs for HP ProBook 445 G8
    - ALSA: hda/realtek: fix mute/micmute LEDs for HP ProBook 630 G8

  * [SRU][OEM-5.10/H] Fix HDMI output issue on Intel TGL GPU (LP: #1934864)
    - drm/i915: Fix HAS_LSPCON macro for platforms between GEN9 and GEN10

  * mute/micmute LEDs no function on HP EliteBook 830 G8 Notebook PC
    (LP: #1934239)
    - ALSA: hda/realtek: fix mute/micmute LEDs for HP EliteBook 830 G8 Notebook PC

  * ubuntu-host driver lacks lseek ops (LP: #1934110)
    - ubuntu-host: add generic lseek op

  * ubuntu_kernel_selftests ftrace fails on arm64 F / aws-5.8 / amd64 F
    azure-5.8 (LP: #1927749)
    - selftests/ftrace: fix event-no-pid on 1-core machine

  * Hirsute update: upstream stable patchset 2021-06-29 (LP: #1934012)
    - proc: Track /proc/$pid/attr/ opener mm_struct
    - ASoC: max98088: fix ni clock divider calculation
    - ASoC: amd: fix for pcm_read() error
    - spi: Fix spi device unregister flow
    - spi: spi-zynq-qspi: Fix stack violation bug
    - bpf: Forbid trampoline attach for functions with variable arguments
    - net/nfc/rawsock.c: fix a permission check bug
    - usb: cdns3: Fix runtime PM imbalance on error
    - ASoC: Intel: bytcr_rt5640: Add quirk for the Glavey TM800A550L tablet
    - ASoC: Intel: bytcr_rt5640: Add quirk for the Lenovo Miix 3-830 tablet
    - vfio-ccw: Reset FSM state to IDLE inside FSM
    - vfio-ccw: Serialize FSM IDLE state with I/O completion
    - ASoC: sti-sas: add missing MODULE_DEVICE_TABLE
    - spi: sprd: Add missing MODULE_DEVICE_TABLE
    - usb: chipidea: udc: assign interrupt number to USB gadget structure
    - isdn: mISDN: netjet: Fix crash in nj_probe:
    - bonding: init notify_work earlier to avoid uninitialized use
    - netlink: disable IRQs for netlink_lock_table()
    - net: mdiobus: get rid of a BUG_ON()
    - cgroup: disable controllers at parse time
    - wq: handle VM suspension in stall detection
    - net/qla3xxx: fix schedule while atomic in ql_sem_spinlock
    - RDS tcp loopback connection can hang
    - net:sfc: fix non-freed irq in legacy irq mode
    - scsi: bnx2fc: Return failure if io_req is already in ABTS processing
    - scsi:...

Changed in linux (Ubuntu Hirsute):
status: Fix Committed → Fix Released
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package linux - 5.13.0-14.14

---------------
linux (5.13.0-14.14) impish; urgency=medium

  * impish/linux: 5.13.0-14.14 -proposed tracker (LP: #1938565)

  * Miscellaneous Ubuntu changes
    - SAUCE: Revert "UBUNTU: SAUCE: random: Make getrandom() ready earlier"
    - SAUCE: random: properly make getrandom() ready earlier

  * Miscellaneous upstream changes
    - seq_buf: Fix overflow in seq_buf_putmem_hex()
    - bpf: Fix integer overflow in argument calculation for bpf_map_area_alloc
    - ext4: cleanup in-core orphan list if ext4_truncate() failed to get a
      transaction handle
    - ext4: fix kernel infoleak via ext4_extent_header
    - ext4: fix overflow in ext4_iomap_alloc()
    - ext4: return error code when ext4_fill_flex_info() fails
    - ext4: correct the cache_nr in tracepoint ext4_es_shrink_exit
    - ext4: remove check for zero nr_to_scan in ext4_es_scan()
    - ext4: fix avefreec in find_group_orlov
    - ext4: use ext4_grp_locked_error in mb_find_extent

 -- Andrea Righi <email address hidden> Mon, 02 Aug 2021 14:23:08 +0200

Changed in linux (Ubuntu):
status: In Progress → Fix Released
Revision history for this message
Ubuntu Kernel Bot (ubuntu-kernel-bot) wrote :

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

tags: added: verification-needed-focal
Revision history for this message
Stefan Bader (smb) wrote :

This is a Hirsute/5.11 change which already got released. The verification request seems to be triggered somehow by the hwe-5.11 kernel. This seems wrong.

tags: removed: verification-needed-focal
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