CVE-2024-26937

Published May 1, 2024

Last updated 2 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: drm/i915/gt: Reset queue_priority_hint on parking Originally, with strict in order execution, we could complete execution only when the queue was empty. Preempt-to-busy allows replacement of an active request that may complete before the preemption is processed by HW. If that happens, the request is retired from the queue, but the queue_priority_hint remains set, preventing direct submission until after the next CS interrupt is processed. This preempt-to-busy race can be triggered by the heartbeat, which will also act as the power-management barrier and upon completion allow us to idle the HW. We may process the completion of the heartbeat, and begin parking the engine before the CS event that restores the queue_priority_hint, causing us to fail the assertion that it is MIN. <3>[ 166.210729] __engine_park:283 GEM_BUG_ON(engine->sched_engine->queue_priority_hint != (-((int)(~0U >> 1)) - 1)) <0>[ 166.210781] Dumping ftrace buffer: <0>[ 166.210795] --------------------------------- ... <0>[ 167.302811] drm_fdin-1097 2..s1. 165741070us : trace_ports: 0000:00:02.0 rcs0: promote { ccid:20 1217:2 prio 0 } <0>[ 167.302861] drm_fdin-1097 2d.s2. 165741072us : execlists_submission_tasklet: 0000:00:02.0 rcs0: preempting last=1217:2, prio=0, hint=2147483646 <0>[ 167.302928] drm_fdin-1097 2d.s2. 165741072us : __i915_request_unsubmit: 0000:00:02.0 rcs0: fence 1217:2, current 0 <0>[ 167.302992] drm_fdin-1097 2d.s2. 165741073us : __i915_request_submit: 0000:00:02.0 rcs0: fence 3:4660, current 4659 <0>[ 167.303044] drm_fdin-1097 2d.s1. 165741076us : execlists_submission_tasklet: 0000:00:02.0 rcs0: context:3 schedule-in, ccid:40 <0>[ 167.303095] drm_fdin-1097 2d.s1. 165741077us : trace_ports: 0000:00:02.0 rcs0: submit { ccid:40 3:4660* prio 2147483646 } <0>[ 167.303159] kworker/-89 11..... 165741139us : i915_request_retire.part.0: 0000:00:02.0 rcs0: fence c90:2, current 2 <0>[ 167.303208] kworker/-89 11..... 165741148us : __intel_context_do_unpin: 0000:00:02.0 rcs0: context:c90 unpin <0>[ 167.303272] kworker/-89 11..... 165741159us : i915_request_retire.part.0: 0000:00:02.0 rcs0: fence 1217:2, current 2 <0>[ 167.303321] kworker/-89 11..... 165741166us : __intel_context_do_unpin: 0000:00:02.0 rcs0: context:1217 unpin <0>[ 167.303384] kworker/-89 11..... 165741170us : i915_request_retire.part.0: 0000:00:02.0 rcs0: fence 3:4660, current 4660 <0>[ 167.303434] kworker/-89 11d..1. 165741172us : __intel_context_retire: 0000:00:02.0 rcs0: context:1216 retire runtime: { total:56028ns, avg:56028ns } <0>[ 167.303484] kworker/-89 11..... 165741198us : __engine_park: 0000:00:02.0 rcs0: parked <0>[ 167.303534] <idle>-0 5d.H3. 165741207us : execlists_irq_handler: 0000:00:02.0 rcs0: semaphore yield: 00000040 <0>[ 167.303583] kworker/-89 11..... 165741397us : __intel_context_retire: 0000:00:02.0 rcs0: context:1217 retire runtime: { total:325575ns, avg:0ns } <0>[ 167.303756] kworker/-89 11..... 165741777us : __intel_context_retire: 0000:00:02.0 rcs0: context:c90 retire runtime: { total:0ns, avg:0ns } <0>[ 167.303806] kworker/-89 11..... 165742017us : __engine_park: __engine_park:283 GEM_BUG_ON(engine->sched_engine->queue_priority_hint != (-((int)(~0U >> 1)) - 1)) <0>[ 167.303811] --------------------------------- <4>[ 167.304722] ------------[ cut here ]------------ <2>[ 167.304725] kernel BUG at drivers/gpu/drm/i915/gt/intel_engine_pm.c:283! <4>[ 167.304731] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI <4>[ 167.304734] CPU: 11 PID: 89 Comm: kworker/11:1 Tainted: G W 6.8.0-rc2-CI_DRM_14193-gc655e0fd2804+ #1 <4>[ 167.304736] Hardware name: Intel Corporation Rocket Lake Client Platform/RocketLake S UDIMM 6L RVP, BIOS RKLSFWI1.R00.3173.A03.2204210138 04/21/2022 <4>[ 167.304738] Workqueue: i915-unordered retire_work_handler [i915] <4>[ 16 ---truncated---
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel, debian_linux

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-617

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.CVE-2026-53362