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CVE-2026-74638— drm/v3d: Serialize the scheduler timeout handlers

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，已修复以下漏洞： drm/v3d：序列化调度器超时处理程序 V3D 暴露了多个独立的硬件队列（BIN、RENDER、TFU 和 CSD），但仅有一个全局重置机制。因此，任何单个队列的超时都必須停止、重置并重新启动所有其他队列的调度器。这使得并发执行的超时处理程序变得不安全。 此前始终无法确保安全，因为驱动程序侧的锁只能覆盖驱动程序的 回调函数。调度器在该回调函数之外处理超时作业及其待处理列表，超出了驱动程序的直接控制范围。因此，由一个队列触发的全局重置仍可能与另一个正在处理自身超时的队列发生

AI Predicted 6.5 Difficulty: Moderate EPSS 0.17% · P6

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux 35e4079bf1a2570abffce6ababa631afcf8ea0e5< 5884851a096d8afcdf91f0e542bac193035183a6 affected
35e4079bf1a2570abffce6ababa631afcf8ea0e5< c22a45817b9c92aa0391db60e2ed467c7e6027d7 affected
35e4079bf1a2570abffce6ababa631afcf8ea0e5< 4da94744707b27a3ae1197bdd7127da4505dc5b1 affected
5235b56b7e5449d990d21d78723b1a5e7bb5738e affected
12125f7d9c15e6d8ac91d10373b2db2f17dcf767 affected
a5f162727b91e480656da1876247a91f651f76de affected
422a8b10ba42097a704d6909ada2956f880246f2 affected
6.1.139< 6.2 affected
… +8 more rows
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I. Basic Information for CVE-2026-74638

Vulnerability Information
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Vulnerability Title
drm/v3d: Serialize the scheduler timeout handlers
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: drm/v3d: Serialize the scheduler timeout handlers V3D exposes several independent hardware queues (BIN, RENDER, TFU and CSD) but has only a single, global reset. A timeout on any one queue therefore has to stop, reset and restart the schedulers of every other queue as well. That makes concurrent timeout handlers unsafe. `reset_lock` was never able to make them safe, as a driver-side lock can only cover the driver's &drm_sched_backend_ops.timedout_job callback. The scheduler handles the timed out job and its pending list around that callback, outside of the driver's control, so a global reset triggered by one queue can still interfere with another queue that is in the middle of handling a timeout of its own. Consequently, if a reset happens in the CSD queue while a CL-intensive application is running, the global reset stops and restarts the CL queue's scheduler while that queue is handling a timeout of its own. As drm_sched_stop() and drm_sched_start() subtract and add the credits of every job sitting on the pending list of the scheduler they are called on, and as the CL queue's handler concurrently takes its job off that same list and puts it back, the stop and the start no longer see the same set of jobs. The CL queue is left with more credits in flight than its limit: [ 327.302739] ------------[ cut here ]------------ [ 327.302744] WARNING: CPU: 2 PID: 43 at drivers/gpu/drm/scheduler/sched_main.c:102 drm_sched_run_job_work+0x238/0x4d0 [gpu_sched] [ 327.302884] CPU: 2 UID: 0 PID: 43 Comm: kworker/u16:1 Not tainted 6.18.39-v8-16k+ #3 PREEMPT [ 327.302889] Hardware name: Raspberry Pi 5 Model B Rev 1.0 (DT) [ 327.302893] Workqueue: v3d_bin drm_sched_run_job_work [gpu_sched] [ 327.302984] Call trace: [ 327.302987] drm_sched_run_job_work+0x238/0x4d0 [gpu_sched] (P) [ 327.302997] process_scheduled_works+0x180/0x3d0 [ 327.303010] worker_thread+0x268/0x3e8 [ 327.303016] kthread+0x140/0x250 [ 327.303022] ret_from_fork+0x10/0x20 [ 327.303031] ---[ end trace 0000000000000000 ]--- From that point on, the credit count of the CL queue is broken, causing a complete GPU hang and UI freeze. The DRM scheduler already provides a mechanism to serialize the timeout handlers of different schedulers: an ordered workqueue passed as drm_sched_init()'s @timeout_wq parameter. By default, each scheduler queues its timeout work on the system workqueue, which runs the handlers concurrently. Give all of the queues a shared ordered workqueue instead, as recommended by the DRM scheduler documentation for hardware that has distinct queues but resets globally.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 35e4079bf1a2570abffce6ababa631afcf8ea0e5 ~ 5884851a096d8afcdf91f0e542bac193035183a6 -
Linux Linux 6.15 -

II. Public POCs for CVE-2026-74638

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III. Intelligence Information for CVE-2026-74638

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Patches & Fixes for CVE-2026-74638 (3)

Same Patch Batch · Linux · 2026-08-22 · 150 CVEs total

CVE-2026-74705 10.0 CRITICAL udp: fix potential use-after-free in tunnel segmentation
CVE-2026-74612 10.0 CRITICAL veth: fix skb length accounting after XDP frag adjustment
CVE-2026-74608 9.8 CRITICAL smb: client: Fix use-after-free in cifs_try_adding_channels()
CVE-2026-74591 9.8 CRITICAL mm/filemap: __filemap_add_folio() restore index before retrying
CVE-2026-74611 9.8 CRITICAL tls: rx: restore msg_iter before TLS 1.3 optimistic retry
CVE-2026-74628 9.8 CRITICAL net/x25: fix use-after-free of the socket by its timers
CVE-2026-74669 9.8 CRITICAL ipvs: clear IPv4 options after rebasing tunnel ICMP errors
CVE-2026-74597 9.8 CRITICAL ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
CVE-2026-74662 9.8 CRITICAL inet: frags: publish queues before arming timer
CVE-2026-74587 9.8 CRITICAL sctp: fix use-after-free of cached ASCONF chunk
CVE-2026-74688 9.8 CRITICAL sctp: clear control chunk transport if it is being removed
CVE-2026-74723 9.8 CRITICAL btrfs: lzo: reject inline extents without valid headers
CVE-2026-74730 9.8 CRITICAL NFS: Pin the 'struct nfs_server' during a FREE_STATEID call
CVE-2026-74617 9.8 CRITICAL dibs: initialise dibs->lock in dibs_dev_alloc()
CVE-2026-74727 9.8 CRITICAL ovpn: skip rehash for peers already removed from by_id
CVE-2026-74586 9.8 CRITICAL sctp: clear new_transport when removing a peer
CVE-2026-74616 9.8 CRITICAL xdp: reject clones that overrun skb_shared_info tailroom
CVE-2026-74588 9.8 CRITICAL sctp: keep chunk->transport in step with the list it is queued on
CVE-2026-74712 9.3 CRITICAL vdpa/mlx5: Fix buffer length in create_direct_keys()
CVE-2026-74665 9.1 CRITICAL net: fix skb length accounting after generic XDP frag adjustment

Showing top 20 of 150 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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