| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
ata: libata-core: Disable LPM on ST1000DM010-2EP102
According to a user report, the ST1000DM010-2EP102 has problems with LPM,
causing random system freezes. The drive belongs to the same BarraCuda
family as the ST2000DM008-2FR102 which has the same issue. |
| In the Linux kernel, the following vulnerability has been resolved:
mmc: core: Avoid bitfield RMW for claim/retune flags
Move claimed and retune control flags out of the bitfield word to
avoid unrelated RMW side effects in asynchronous contexts.
The host->claimed bit shared a word with retune flags. Writes to claimed
in __mmc_claim_host() or retune_now in mmc_mq_queue_rq() can overwrite
other bits when concurrent updates happen in other contexts, triggering
spurious WARN_ON(!host->claimed). Convert claimed, can_retune,
retune_now and retune_paused to bool to remove shared-word coupling. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated
Explicitly set/clear CR8 write interception when AVIC is (de)activated to
fix a bug where KVM leaves the interception enabled after AVIC is
activated. E.g. if KVM emulates INIT=>WFS while AVIC is deactivated, CR8
will remain intercepted in perpetuity.
On its own, the dangling CR8 intercept is "just" a performance issue, but
combined with the TPR sync bug fixed by commit d02e48830e3f ("KVM: SVM:
Sync TPR from LAPIC into VMCB::V_TPR even if AVIC is active"), the danging
intercept is fatal to Windows guests as the TPR seen by hardware gets
wildly out of sync with reality.
Note, VMX isn't affected by the bug as TPR_THRESHOLD is explicitly ignored
when Virtual Interrupt Delivery is enabled, i.e. when APICv is active in
KVM's world. I.e. there's no need to trigger update_cr8_intercept(), this
is firmly an SVM implementation flaw/detail.
WARN if KVM gets a CR8 write #VMEXIT while AVIC is active, as KVM should
never enter the guest with AVIC enabled and CR8 writes intercepted.
[Squash fix to avic_deactivate_vmcb. - Paolo] |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: codecs: rt1011: Use component to get the dapm context in spk_mode_put
The correct helper to use in rt1011_recv_spk_mode_put() to retrieve the
DAPM context is snd_soc_component_to_dapm(), from kcontrol we will
receive NULL pointer. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/i915/vrr: Configure VRR timings after enabling TRANS_DDI_FUNC_CTL
Apparently ICL may hang with an MCE if we write TRANS_VRR_VMAX/FLIPLINE
before enabling TRANS_DDI_FUNC_CTL.
Personally I was only able to reproduce a hang (on an Dell XPS 7390
2-in-1) with an external display connected via a dock using a dodgy
type-C cable that made the link training fail. After the failed
link training the machine would hang. TGL seemed immune to the
problem for whatever reason.
BSpec does tell us to configure VRR after enabling TRANS_DDI_FUNC_CTL
as well. The DMC firmware also does the VRR restore in two stages:
- first stage seems to be unconditional and includes TRANS_VRR_CTL
and a few other VRR registers, among other things
- second stage is conditional on the DDI being enabled,
and includes TRANS_DDI_FUNC_CTL and TRANS_VRR_VMAX/VMIN/FLIPLINE,
among other things
So let's reorder the steps to match to avoid the hang, and
toss in an extra WARN to make sure we don't screw this up later.
BSpec: 22243
(cherry picked from commit 93f3a267c3dd4d811b224bb9e179a10d81456a74) |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: storvsc: Fix scheduling while atomic on PREEMPT_RT
This resolves the follow splat and lock-up when running with PREEMPT_RT
enabled on Hyper-V:
[ 415.140818] BUG: scheduling while atomic: stress-ng-iomix/1048/0x00000002
[ 415.140822] INFO: lockdep is turned off.
[ 415.140823] Modules linked in: intel_rapl_msr intel_rapl_common intel_uncore_frequency_common intel_pmc_core pmt_telemetry pmt_discovery pmt_class intel_pmc_ssram_telemetry intel_vsec ghash_clmulni_intel aesni_intel rapl binfmt_misc nls_ascii nls_cp437 vfat fat snd_pcm hyperv_drm snd_timer drm_client_lib drm_shmem_helper snd sg soundcore drm_kms_helper pcspkr hv_balloon hv_utils evdev joydev drm configfs efi_pstore nfnetlink vsock_loopback vmw_vsock_virtio_transport_common hv_sock vmw_vsock_vmci_transport vsock vmw_vmci efivarfs autofs4 ext4 crc16 mbcache jbd2 sr_mod sd_mod cdrom hv_storvsc serio_raw hid_generic scsi_transport_fc hid_hyperv scsi_mod hid hv_netvsc hyperv_keyboard scsi_common
[ 415.140846] Preemption disabled at:
[ 415.140847] [<ffffffffc0656171>] storvsc_queuecommand+0x2e1/0xbe0 [hv_storvsc]
[ 415.140854] CPU: 8 UID: 0 PID: 1048 Comm: stress-ng-iomix Not tainted 6.19.0-rc7 #30 PREEMPT_{RT,(full)}
[ 415.140856] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 09/04/2024
[ 415.140857] Call Trace:
[ 415.140861] <TASK>
[ 415.140861] ? storvsc_queuecommand+0x2e1/0xbe0 [hv_storvsc]
[ 415.140863] dump_stack_lvl+0x91/0xb0
[ 415.140870] __schedule_bug+0x9c/0xc0
[ 415.140875] __schedule+0xdf6/0x1300
[ 415.140877] ? rtlock_slowlock_locked+0x56c/0x1980
[ 415.140879] ? rcu_is_watching+0x12/0x60
[ 415.140883] schedule_rtlock+0x21/0x40
[ 415.140885] rtlock_slowlock_locked+0x502/0x1980
[ 415.140891] rt_spin_lock+0x89/0x1e0
[ 415.140893] hv_ringbuffer_write+0x87/0x2a0
[ 415.140899] vmbus_sendpacket_mpb_desc+0xb6/0xe0
[ 415.140900] ? rcu_is_watching+0x12/0x60
[ 415.140902] storvsc_queuecommand+0x669/0xbe0 [hv_storvsc]
[ 415.140904] ? HARDIRQ_verbose+0x10/0x10
[ 415.140908] ? __rq_qos_issue+0x28/0x40
[ 415.140911] scsi_queue_rq+0x760/0xd80 [scsi_mod]
[ 415.140926] __blk_mq_issue_directly+0x4a/0xc0
[ 415.140928] blk_mq_issue_direct+0x87/0x2b0
[ 415.140931] blk_mq_dispatch_queue_requests+0x120/0x440
[ 415.140933] blk_mq_flush_plug_list+0x7a/0x1a0
[ 415.140935] __blk_flush_plug+0xf4/0x150
[ 415.140940] __submit_bio+0x2b2/0x5c0
[ 415.140944] ? submit_bio_noacct_nocheck+0x272/0x360
[ 415.140946] submit_bio_noacct_nocheck+0x272/0x360
[ 415.140951] ext4_read_bh_lock+0x3e/0x60 [ext4]
[ 415.140995] ext4_block_write_begin+0x396/0x650 [ext4]
[ 415.141018] ? __pfx_ext4_da_get_block_prep+0x10/0x10 [ext4]
[ 415.141038] ext4_da_write_begin+0x1c4/0x350 [ext4]
[ 415.141060] generic_perform_write+0x14e/0x2c0
[ 415.141065] ext4_buffered_write_iter+0x6b/0x120 [ext4]
[ 415.141083] vfs_write+0x2ca/0x570
[ 415.141087] ksys_write+0x76/0xf0
[ 415.141089] do_syscall_64+0x99/0x1490
[ 415.141093] ? rcu_is_watching+0x12/0x60
[ 415.141095] ? finish_task_switch.isra.0+0xdf/0x3d0
[ 415.141097] ? rcu_is_watching+0x12/0x60
[ 415.141098] ? lock_release+0x1f0/0x2a0
[ 415.141100] ? rcu_is_watching+0x12/0x60
[ 415.141101] ? finish_task_switch.isra.0+0xe4/0x3d0
[ 415.141103] ? rcu_is_watching+0x12/0x60
[ 415.141104] ? __schedule+0xb34/0x1300
[ 415.141106] ? hrtimer_try_to_cancel+0x1d/0x170
[ 415.141109] ? do_nanosleep+0x8b/0x160
[ 415.141111] ? hrtimer_nanosleep+0x89/0x100
[ 415.141114] ? __pfx_hrtimer_wakeup+0x10/0x10
[ 415.141116] ? xfd_validate_state+0x26/0x90
[ 415.141118] ? rcu_is_watching+0x12/0x60
[ 415.141120] ? do_syscall_64+0x1e0/0x1490
[ 415.141121] ? do_syscall_64+0x1e0/0x1490
[ 415.141123] ? rcu_is_watching+0x12/0x60
[ 415.141124] ? do_syscall_64+0x1e0/0x1490
[ 415.141125] ? do_syscall_64+0x1e0/0x1490
[ 415.141127] ? irqentry_exit+0x140/0
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
USB: usbtmc: Use usb_bulk_msg_killable() with user-specified timeouts
The usbtmc driver accepts timeout values specified by the user in an
ioctl command, and uses these timeouts for some usb_bulk_msg() calls.
Since the user can specify arbitrarily long timeouts and
usb_bulk_msg() uses unkillable waits, call usb_bulk_msg_killable()
instead to avoid the possibility of the user hanging a kernel thread
indefinitely. |
| In the Linux kernel, the following vulnerability has been resolved:
USB: core: Limit the length of unkillable synchronous timeouts
The usb_control_msg(), usb_bulk_msg(), and usb_interrupt_msg() APIs in
usbcore allow unlimited timeout durations. And since they use
uninterruptible waits, this leaves open the possibility of hanging a
task for an indefinitely long time, with no way to kill it short of
unplugging the target device.
To prevent this sort of problem, enforce a maximum limit on the length
of these unkillable timeouts. The limit chosen here, somewhat
arbitrarily, is 60 seconds. On many systems (although not all) this
is short enough to avoid triggering the kernel's hung-task detector.
In addition, clear up the ambiguity of negative timeout values by
treating them the same as 0, i.e., using the maximum allowed timeout. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: image: mdc800: kill download URB on timeout
mdc800_device_read() submits download_urb and waits for completion.
If the timeout fires and the device has not responded, the function
returns without killing the URB, leaving it active.
A subsequent read() resubmits the same URB while it is still
in-flight, triggering the WARN in usb_submit_urb():
"URB submitted while active"
Check the return value of wait_event_timeout() and kill the URB if
it indicates timeout, ensuring the URB is complete before its status
is inspected or the URB is resubmitted.
Similar to
- commit 372c93131998 ("USB: yurex: fix control-URB timeout handling")
- commit b98d5000c505 ("media: rc: iguanair: handle timeouts") |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: add upper bound check on user inputs in signal ioctl
Huge input values in amdgpu_userq_signal_ioctl can lead to a OOM and
could be exploited.
So check these input value against AMDGPU_USERQ_MAX_HANDLES
which is big enough value for genuine use cases and could
potentially avoid OOM.
(cherry picked from commit be267e15f99bc97cbe202cd556717797cdcf79a5) |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: add upper bound check on user inputs in wait ioctl
Huge input values in amdgpu_userq_wait_ioctl can lead to a OOM and
could be exploited.
So check these input value against AMDGPU_USERQ_MAX_HANDLES
which is big enough value for genuine use cases and could
potentially avoid OOM.
v2: squash in Srini's fix
(cherry picked from commit fcec012c664247531aed3e662f4280ff804d1476) |
| In the Linux kernel, the following vulnerability has been resolved:
x86/apic: Disable x2apic on resume if the kernel expects so
When resuming from s2ram, firmware may re-enable x2apic mode, which may have
been disabled by the kernel during boot either because it doesn't support IRQ
remapping or for other reasons. This causes the kernel to continue using the
xapic interface, while the hardware is in x2apic mode, which causes hangs.
This happens on defconfig + bare metal + s2ram.
Fix this in lapic_resume() by disabling x2apic if the kernel expects it to be
disabled, i.e. when x2apic_mode = 0.
The ACPI v6.6 spec, Section 16.3 [1] says firmware restores either the
pre-sleep configuration or initial boot configuration for each CPU, including
MSR state:
When executing from the power-on reset vector as a result of waking from an
S2 or S3 sleep state, the platform firmware performs only the hardware
initialization required to restore the system to either the state the
platform was in prior to the initial operating system boot, or to the
pre-sleep configuration state. In multiprocessor systems, non-boot
processors should be placed in the same state as prior to the initial
operating system boot.
(further ahead)
If this is an S2 or S3 wake, then the platform runtime firmware restores
minimum context of the system before jumping to the waking vector. This
includes:
CPU configuration. Platform runtime firmware restores the pre-sleep
configuration or initial boot configuration of each CPU (MSR, MTRR,
firmware update, SMBase, and so on). Interrupts must be disabled (for
IA-32 processors, disabled by CLI instruction).
(and other things)
So at least as per the spec, re-enablement of x2apic by the firmware is
allowed if "x2apic on" is a part of the initial boot configuration.
[1] https://uefi.org/specs/ACPI/6.6/16_Waking_and_Sleeping.html#initialization
[ bp: Massage. ] |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix transaction abort when snapshotting received subvolumes
Currently a user can trigger a transaction abort by snapshotting a
previously received snapshot a bunch of times until we reach a
BTRFS_UUID_KEY_RECEIVED_SUBVOL item overflow (the maximum item size we
can store in a leaf). This is very likely not common in practice, but
if it happens, it turns the filesystem into RO mode. The snapshot, send
and set_received_subvol and subvol_setflags (used by receive) don't
require CAP_SYS_ADMIN, just inode_owner_or_capable(). A malicious user
could use this to turn a filesystem into RO mode and disrupt a system.
Reproducer script:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdi
MNT=/mnt/sdi
# Use smallest node size to make the test faster.
mkfs.btrfs -f --nodesize 4K $DEV
mount $DEV $MNT
# Create a subvolume and set it to RO so that it can be used for send.
btrfs subvolume create $MNT/sv
touch $MNT/sv/foo
btrfs property set $MNT/sv ro true
# Send and receive the subvolume into snaps/sv.
mkdir $MNT/snaps
btrfs send $MNT/sv | btrfs receive $MNT/snaps
# Now snapshot the received subvolume, which has a received_uuid, a
# lot of times to trigger the leaf overflow.
total=500
for ((i = 1; i <= $total; i++)); do
echo -ne "\rCreating snapshot $i/$total"
btrfs subvolume snapshot -r $MNT/snaps/sv $MNT/snaps/sv_$i > /dev/null
done
echo
umount $MNT
When running the test:
$ ./test.sh
(...)
Create subvolume '/mnt/sdi/sv'
At subvol /mnt/sdi/sv
At subvol sv
Creating snapshot 496/500ERROR: Could not create subvolume: Value too large for defined data type
Creating snapshot 497/500ERROR: Could not create subvolume: Read-only file system
Creating snapshot 498/500ERROR: Could not create subvolume: Read-only file system
Creating snapshot 499/500ERROR: Could not create subvolume: Read-only file system
Creating snapshot 500/500ERROR: Could not create subvolume: Read-only file system
And in dmesg/syslog:
$ dmesg
(...)
[251067.627338] BTRFS warning (device sdi): insert uuid item failed -75 (0x4628b21c4ac8d898, 0x2598bee2b1515c91) type 252!
[251067.629212] ------------[ cut here ]------------
[251067.630033] BTRFS: Transaction aborted (error -75)
[251067.630871] WARNING: fs/btrfs/transaction.c:1907 at create_pending_snapshot.cold+0x52/0x465 [btrfs], CPU#10: btrfs/615235
[251067.632851] Modules linked in: btrfs dm_zero (...)
[251067.644071] CPU: 10 UID: 0 PID: 615235 Comm: btrfs Tainted: G W 6.19.0-rc8-btrfs-next-225+ #1 PREEMPT(full)
[251067.646165] Tainted: [W]=WARN
[251067.646733] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[251067.648735] RIP: 0010:create_pending_snapshot.cold+0x55/0x465 [btrfs]
[251067.649984] Code: f0 48 0f (...)
[251067.653313] RSP: 0018:ffffce644908fae8 EFLAGS: 00010292
[251067.653987] RAX: 00000000ffffff01 RBX: ffff8e5639e63a80 RCX: 00000000ffffffd3
[251067.655042] RDX: ffff8e53faa76b00 RSI: 00000000ffffffb5 RDI: ffffffffc0919750
[251067.656077] RBP: ffffce644908fbd8 R08: 0000000000000000 R09: ffffce644908f820
[251067.657068] R10: ffff8e5adc1fffa8 R11: 0000000000000003 R12: ffff8e53c0431bd0
[251067.658050] R13: ffff8e5414593600 R14: ffff8e55efafd000 R15: 00000000ffffffb5
[251067.659019] FS: 00007f2a4944b3c0(0000) GS:ffff8e5b27dae000(0000) knlGS:0000000000000000
[251067.660115] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[251067.660943] CR2: 00007ffc5aa57898 CR3: 00000005813a2003 CR4: 0000000000370ef0
[251067.661972] Call Trace:
[251067.662292] <TASK>
[251067.662653] create_pending_snapshots+0x97/0xc0 [btrfs]
[251067.663413] btrfs_commit_transaction+0x26e/0xc00 [btrfs]
[251067.664257] ? btrfs_qgroup_convert_reserved_meta+0x35/0x390 [btrfs]
[251067.665238] ? _raw_spin_unlock+0x15/0x30
[251067.665837] ? record_root_
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Eagerly init vgic dist/redist on vgic creation
If vgic_allocate_private_irqs_locked() fails for any odd reason,
we exit kvm_vgic_create() early, leaving dist->rd_regions uninitialised.
kvm_vgic_dist_destroy() then comes along and walks into the weeds
trying to free the RDs. Got to love this stuff.
Solve it by moving all the static initialisation early, and make
sure that if we fail halfway, we're in a reasonable shape to
perform the rest of the teardown. While at it, reset the vgic model
on failure, just in case... |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: reserve enough transaction items for qgroup ioctls
Currently our qgroup ioctls don't reserve any space, they just do a
transaction join, which does not reserve any space, neither for the quota
tree updates nor for the delayed refs generated when updating the quota
tree. The quota root uses the global block reserve, which is fine most of
the time since we don't expect a lot of updates to the quota root, or to
be too close to -ENOSPC such that other critical metadata updates need to
resort to the global reserve.
However this is not optimal, as not reserving proper space may result in a
transaction abort due to not reserving space for delayed refs and then
abusing the use of the global block reserve.
For example, the following reproducer (which is unlikely to model any
real world use case, but just to illustrate the problem), triggers such a
transaction abort due to -ENOSPC when running delayed refs:
$ cat test.sh
#!/bin/bash
DEV=/dev/nullb0
MNT=/mnt/nullb0
umount $DEV &> /dev/null
# Limit device to 1G so that it's much faster to reproduce the issue.
mkfs.btrfs -f -b 1G $DEV
mount -o commit=600 $DEV $MNT
fallocate -l 800M $MNT/filler
btrfs quota enable $MNT
for ((i = 1; i <= 400000; i++)); do
btrfs qgroup create 1/$i $MNT
done
umount $MNT
When running this, we can see in dmesg/syslog that a transaction abort
happened:
[436.490] BTRFS error (device nullb0): failed to run delayed ref for logical 30408704 num_bytes 16384 type 176 action 1 ref_mod 1: -28
[436.493] ------------[ cut here ]------------
[436.494] BTRFS: Transaction aborted (error -28)
[436.495] WARNING: fs/btrfs/extent-tree.c:2247 at btrfs_run_delayed_refs+0xd9/0x110 [btrfs], CPU#4: umount/2495372
[436.497] Modules linked in: btrfs loop (...)
[436.508] CPU: 4 UID: 0 PID: 2495372 Comm: umount Tainted: G W 6.19.0-rc8-btrfs-next-225+ #1 PREEMPT(full)
[436.510] Tainted: [W]=WARN
[436.511] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[436.513] RIP: 0010:btrfs_run_delayed_refs+0xdf/0x110 [btrfs]
[436.514] Code: 0f 82 ea (...)
[436.518] RSP: 0018:ffffd511850b7d78 EFLAGS: 00010292
[436.519] RAX: 00000000ffffffe4 RBX: ffff8f120dad37e0 RCX: 0000000002040001
[436.520] RDX: 0000000000000002 RSI: 00000000ffffffe4 RDI: ffffffffc090fd80
[436.522] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffffc04d1867
[436.523] R10: ffff8f18dc1fffa8 R11: 0000000000000003 R12: ffff8f173aa89400
[436.524] R13: 0000000000000000 R14: ffff8f173aa89400 R15: 0000000000000000
[436.526] FS: 00007fe59045d840(0000) GS:ffff8f192e22e000(0000) knlGS:0000000000000000
[436.527] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[436.528] CR2: 00007fe5905ff2b0 CR3: 000000060710a002 CR4: 0000000000370ef0
[436.530] Call Trace:
[436.530] <TASK>
[436.530] btrfs_commit_transaction+0x73/0xc00 [btrfs]
[436.531] ? btrfs_attach_transaction_barrier+0x1e/0x70 [btrfs]
[436.532] sync_filesystem+0x7a/0x90
[436.533] generic_shutdown_super+0x28/0x180
[436.533] kill_anon_super+0x12/0x40
[436.534] btrfs_kill_super+0x12/0x20 [btrfs]
[436.534] deactivate_locked_super+0x2f/0xb0
[436.534] cleanup_mnt+0xea/0x180
[436.535] task_work_run+0x58/0xa0
[436.535] exit_to_user_mode_loop+0xed/0x480
[436.536] ? __x64_sys_umount+0x68/0x80
[436.536] do_syscall_64+0x2a5/0xf20
[436.537] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[436.537] RIP: 0033:0x7fe5906b6217
[436.538] Code: 0d 00 f7 (...)
[436.540] RSP: 002b:00007ffcd87a61f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[436.541] RAX: 0000000000000000 RBX: 00005618b9ecadc8 RCX: 00007fe5906b6217
[436.541] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005618b9ecb100
[436.542] RBP: 0000000000000000 R08: 00007ffcd87a4fe0 R09: 00000000ffffffff
[436.544] R10: 0000000000000103 R11:
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mvm: don't send a 6E related command when not supported
MCC_ALLOWED_AP_TYPE_CMD is related to 6E support. Do not send it if the
device doesn't support 6E.
Apparently, the firmware is mistakenly advertising support for this
command even on AX201 which does not support 6E and then the firmware
crashes. |
| In the Linux kernel, the following vulnerability has been resolved:
sched/fair: Fix zero_vruntime tracking fix
John reported that stress-ng-yield could make his machine unhappy and
managed to bisect it to commit b3d99f43c72b ("sched/fair: Fix
zero_vruntime tracking").
The combination of yield and that commit was specific enough to
hypothesize the following scenario:
Suppose we have 2 runnable tasks, both doing yield. Then one will be
eligible and one will not be, because the average position must be in
between these two entities.
Therefore, the runnable task will be eligible, and be promoted a full
slice (all the tasks do is yield after all). This causes it to jump over
the other task and now the other task is eligible and current is no
longer. So we schedule.
Since we are runnable, there is no {de,en}queue. All we have is the
__{en,de}queue_entity() from {put_prev,set_next}_task(). But per the
fingered commit, those two no longer move zero_vruntime.
All that moves zero_vruntime are tick and full {de,en}queue.
This means, that if the two tasks playing leapfrog can reach the
critical speed to reach the overflow point inside one tick's worth of
time, we're up a creek.
Additionally, when multiple cgroups are involved, there is no guarantee
the tick will in fact hit every cgroup in a timely manner. Statistically
speaking it will, but that same statistics does not rule out the
possibility of one cgroup not getting a tick for a significant amount of
time -- however unlikely.
Therefore, just like with the yield() case, force an update at the end
of every slice. This ensures the update is never more than a single
slice behind and the whole thing is within 2 lag bounds as per the
comment on entity_key(). |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix dsc eDP issue
[why]
Need to add function hook check before use |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: fix sync handling in amdgpu_dma_buf_move_notify
Invalidating a dmabuf will impact other users of the shared BO.
In the scenario where process A moves the BO, it needs to inform
process B about the move and process B will need to update its
page table.
The commit fixes a synchronisation bug caused by the use of the
ticket: it made amdgpu_vm_handle_moved behave as if updating
the page table immediately was correct but in this case it's not.
An example is the following scenario, with 2 GPUs and glxgears
running on GPU0 and Xorg running on GPU1, on a system where P2P
PCI isn't supported:
glxgears:
export linear buffer from GPU0 and import using GPU1
submit frame rendering to GPU0
submit tiled->linear blit
Xorg:
copy of linear buffer
The sequence of jobs would be:
drm_sched_job_run # GPU0, frame rendering
drm_sched_job_queue # GPU0, blit
drm_sched_job_done # GPU0, frame rendering
drm_sched_job_run # GPU0, blit
move linear buffer for GPU1 access #
amdgpu_dma_buf_move_notify -> update pt # GPU0
It this point the blit job on GPU0 is still running and would
likely produce a page fault. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: nSVM: Remove a user-triggerable WARN on nested_svm_load_cr3() succeeding
Drop the WARN in svm_set_nested_state() on nested_svm_load_cr3() failing
as it is trivially easy to trigger from userspace by modifying CPUID after
loading CR3. E.g. modifying the state restoration selftest like so:
--- tools/testing/selftests/kvm/x86/state_test.c
+++ tools/testing/selftests/kvm/x86/state_test.c
@@ -280,7 +280,16 @@ int main(int argc, char *argv[])
/* Restore state in a new VM. */
vcpu = vm_recreate_with_one_vcpu(vm);
- vcpu_load_state(vcpu, state);
+
+ if (stage == 4) {
+ state->sregs.cr3 = BIT(44);
+ vcpu_load_state(vcpu, state);
+
+ vcpu_set_cpuid_property(vcpu, X86_PROPERTY_MAX_PHY_ADDR, 36);
+ __vcpu_nested_state_set(vcpu, &state->nested);
+ } else {
+ vcpu_load_state(vcpu, state);
+ }
/*
* Restore XSAVE state in a dummy vCPU, first without doing
generates:
WARNING: CPU: 30 PID: 938 at arch/x86/kvm/svm/nested.c:1877 svm_set_nested_state+0x34a/0x360 [kvm_amd]
Modules linked in: kvm_amd kvm irqbypass [last unloaded: kvm]
CPU: 30 UID: 1000 PID: 938 Comm: state_test Tainted: G W 6.18.0-rc7-58e10b63777d-next-vm
Tainted: [W]=WARN
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:svm_set_nested_state+0x34a/0x360 [kvm_amd]
Call Trace:
<TASK>
kvm_arch_vcpu_ioctl+0xf33/0x1700 [kvm]
kvm_vcpu_ioctl+0x4e6/0x8f0 [kvm]
__x64_sys_ioctl+0x8f/0xd0
do_syscall_64+0x61/0xad0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Simply delete the WARN instead of trying to prevent userspace from shoving
"illegal" state into CR3. For better or worse, KVM's ABI allows userspace
to set CPUID after SREGS, and vice versa, and KVM is very permissive when
it comes to guest CPUID. I.e. attempting to enforce the virtual CPU model
when setting CPUID could break userspace. Given that the WARN doesn't
provide any meaningful protection for KVM or benefit for userspace, simply
drop it even though the odds of breaking userspace are minuscule.
Opportunistically delete a spurious newline. |
