Linux kernel source tree
Go to file
Luigi Santivetti cf385cf6e7 drm/imagination: fix error checking of pvr_vm_context_lookup()
Since pvr_vm_context_lookup() returns either NULL or a pointer, then stop
using IS_ERR() for checking the return value.

Using IS_ERR() leads to the kernel oops reported below. It can be
reproduced by passing an invalid VM context handle from userspace to the
DRM_IOCTL_PVR_CREATE_CONTEXT ioctl.

[   92.733119] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000148
[   92.742042] Mem abort info:
[   92.744890]   ESR = 0x0000000096000004
[   92.748686]   EC = 0x25: DABT (current EL), IL = 32 bits
[   92.754020]   SET = 0, FnV = 0
[   92.757154]   EA = 0, S1PTW = 0
[   92.760337]   FSC = 0x04: level 0 translation fault
[   92.765243] Data abort info:
[   92.768129]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[   92.773626]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[   92.778763]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[   92.784098] user pgtable: 4k pages, 48-bit VAs, pgdp=000000088ed23000
[   92.790550] [0000000000000148] pgd=0000000000000000, p4d=0000000000000000
[   92.797381] Internal error: Oops: 0000000096000004 [#1]  SMP
[   92.803027] Modules linked in: powervr
[   92.852533] CPU: 0 UID: 0 PID: 409 Comm: triangle Not tainted 7.1.0-rc5-g98b46e693b91 #1 PREEMPT
[   92.861385] Hardware name: Texas Instruments AM68 SK (DT)
[   92.866766] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   92.873709] pc : pvr_vm_get_fw_mem_context+0x0/0xc [powervr]
[   92.879376] lr : pvr_queue_create+0x26c/0x440 [powervr]
[   92.884595] sp : ffff8000837fbb00
[   92.887895] x29: ffff8000837fbb60 x28: 0000000000000000 x27: ffff8000837fbce8
[   92.895015] x26: ffff000807f61a40 x25: ffff000807f61a00 x24: ffff000807f64400
[   92.902135] x23: ffff00080a5ab000 x22: ffff800079b24730 x21: ffff000807f61800
[   92.909254] x20: ffff00080999e680 x19: 0000000000000000 x18: 0000000000000000
[   92.916373] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000001
[   92.923492] x14: 0000000000000000 x13: 0000000000000002 x12: ffff80008145b298
[   92.930611] x11: ffff8000844e5000 x10: ffff80008165a130 x9 : 0000000000000100
[   92.937730] x8 : 0000000000000001 x7 : ffff0008076b27e0 x6 : ffff00080ec43b7c
[   92.944850] x5 : ffff00080ec43b78 x4 : 0000000000000000 x3 : ffff00080999e680
[   92.951968] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
[   92.959088] Call trace:
[   92.961521]  pvr_vm_get_fw_mem_context+0x0/0xc [powervr] (P)
[   92.967173]  pvr_context_create+0x190/0x410 [powervr]
[   92.972218]  pvr_ioctl_create_context+0x44/0x8c [powervr]
[   92.977608]  drm_ioctl_kernel+0xbc/0x124 [drm]
[   92.982127]  drm_ioctl+0x1f8/0x4dc [drm]
[   92.986098]  __arm64_sys_ioctl+0xac/0x104
[   92.990102]  invoke_syscall+0x54/0x10c
[   92.993842]  el0_svc_common.constprop.0+0x40/0xe0
[   92.998532]  do_el0_svc+0x1c/0x28
[   93.001835]  el0_svc+0x38/0x11c
[   93.004969]  el0t_64_sync_handler+0xa0/0xe4
[   93.009139]  el0t_64_sync+0x198/0x19c
[   93.012792] Code: aa1703e0 d2800014 95cb0ba4 17ffffe8 (f940a400)
[   93.018869] ---[ end trace 0000000000000000 ]---

Fixes: d2d79d29bb ("drm/imagination: Implement context creation/destruction ioctls")
Cc: stable@vger.kernel.org
Signed-off-by: Luigi Santivetti <luigi.santivetti@imgtec.com>
Reviewed-by: Alessio Belle <alessio.belle@imgtec.com>
Link: https://patch.msgid.link/20260707-staging-ddkopsrc-2435-v1-1-24e160d44476@imgtec.com
Signed-off-by: Alessio Belle <alessio.belle@imgtec.com>
2026-07-09 15:07:32 +01:00
arch LoongArch changes for v7.2 2026-06-26 08:42:49 -07:00
block block: handle REQ_OP_ZONE_APPEND in __bio_integrity_action 2026-06-24 06:53:25 -06:00
certs treewide: fix indentation and whitespace in Kconfig files 2026-05-28 21:24:42 -07:00
crypto mm.git review status for mm-hotfixes-stable..mm-nonmm-stable 2026-06-21 13:20:19 -07:00
Documentation RTC for 7.2 2026-06-27 11:00:18 -07:00
drivers drm/imagination: fix error checking of pvr_vm_context_lookup() 2026-07-09 15:07:32 +01:00
fs fscrypt fixes for 7.2 2026-06-27 09:20:16 -07:00
include drm/drm_exec: avoid indirect goto 2026-07-07 14:02:53 +02:00
init mm.git review status for mm-hotfixes-stable..mm-nonmm-stable 2026-06-21 13:20:19 -07:00
io_uring io_uring-7.2-20260625 2026-06-25 09:53:31 -07:00
ipc kernel-7.2-rc1.misc 2026-06-15 03:05:50 +05:30
kernel Power management fixes for 7.2-rc1 2026-06-26 13:14:18 -07:00
lib Misc fixes: 2026-06-23 16:05:54 -07:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm block-7.2-20260625 2026-06-25 09:56:47 -07:00
net bpf-fixes 2026-06-25 14:09:26 -07:00
rust Rust changes for v7.2 (addendum) 2026-06-24 15:11:08 -07:00
samples Char/Misc/IIO/FPGA/GPIB/etc driver updates for 7.2-rc1 2026-06-22 12:20:21 -07:00
scripts Second round of Kbuild changes for 7.2 2026-06-25 09:06:12 -07:00
security * add Georgia Garcia as co-maintainer of apparmor 2026-06-24 12:33:40 -07:00
sound sound fixes for 7.2-rc1 2026-06-27 12:15:23 -07:00
tools LoongArch changes for v7.2 2026-06-26 08:42:49 -07:00
usr kbuild: uapi: also test UAPI headers against C++ compilers 2026-03-25 13:24:42 +01:00
virt s390: 2026-06-25 10:21:13 -07:00
.clang-format clang-format: fix formatting of guard() and scoped_guard() statements 2026-05-28 21:24:41 -07:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +02:00
.cocciconfig
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add myself 2026-04-02 16:48:25 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore SPDX patches for 7.2-rc1 2026-06-22 12:06:22 -07:00
.mailmap Including fixes from netfilter and IPsec. 2026-06-25 12:25:36 -07:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mm.git review status for mm-hotfixes-stable..mm-nonmm-stable 2026-06-21 13:20:19 -07:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Including fixes from netfilter and IPsec. 2026-06-25 12:25:36 -07:00
Makefile Linux 7.2-rc1 2026-06-28 12:01:31 -07:00
README docs: add AI Coding Assistants documentation 2026-01-06 14:55:06 -07:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros
* AI Coding Assistant - LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst