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. 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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. 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Short summary of fixes pull:
DRM core and helpers:
- calculate framebuffer geometry with format helpers
- fix docs
appletbdrm:
- allocate protocol buffers with kvzalloc()
dma-buf:
- fix docs
imagination:
- avoid segfault in debugfs
ofdrm:
- put PCI device reference on errors
udl:
- increase USB timeout
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patch.msgid.link/20260430064521.GA14957@linux.fritz.box
[WHY]
A situation has occurred where udl_handle_damage() executed successfully
and the kernel log appears normal, but the display fails to show any output.
This is because the call to udl_get_urb() in udl_crtc_helper_atomic_enable()
failed without generating any error message.
[HOW]
1. Increase timeout of getting urb.
2. Add error messages when calling udl_get_urb() failed in
udl_crtc_helper_atomic_enable().
Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 5320918b9a87 ("drm/udl: initial UDL driver (v4)")
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: <stable@vger.kernel.org> # v3.4+
Link: https://patch.msgid.link/20260424124427.657-1-oushixiong1025@163.com
Pull clk fix from Stephen Boyd:
"One more fix for the merge window to avoid a boot hang on
Raspberry Pi 3B by marking the VEC clk critical so that it
doesn't get turned off and hang the bus"
* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
clk: bcm: rpi: Mark VEC clock as CLK_IGNORE_UNUSED
Fix invalid data access by passing right data for debugfs entry.
[ 171.549793] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[ 171.559248] Mem abort info:
[ 171.562173] ESR = 0x0000000096000044
[ 171.566227] EC = 0x25: DABT (current EL), IL = 32 bits
[ 171.573108] SET = 0, FnV = 0
[ 171.576448] EA = 0, S1PTW = 0
[ 171.579745] FSC = 0x04: level 0 translation fault
[ 171.584760] Data abort info:
[ 171.588012] ISV = 0, ISS = 0x00000044, ISS2 = 0x00000000
[ 171.593734] CM = 0, WnR = 1, TnD = 0, TagAccess = 0
[ 171.598962] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 171.604471] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000083837000
[ 171.611358] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
[ 171.618500] Internal error: Oops: 0000000096000044 [#1] SMP
[ 171.624222] Modules linked in: powervr drm_shmem_helper drm_gpuvm...
[ 171.656580] CPU: 0 UID: 0 PID: 549 Comm: bash Not tainted 7.0.0-rc2-g730b257ba723-dirty #13 PREEMPT
[ 171.665773] Hardware name: BeagleBoard.org BeaglePlay (DT)
[ 171.671296] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 171.678306] pc : pvr_fw_trace_mask_set+0x78/0x154 [powervr]
[ 171.683959] lr : pvr_fw_trace_mask_set+0x4c/0x154 [powervr]
[ 171.689593] sp : ffff8000835ebb90
[ 171.692929] x29: ffff8000835ebc00 x28: ffff000005c60f80 x27: 0000000000000000
[ 171.700130] x26: 0000000000000000 x25: ffff00000504af28 x24: 0000000000000000
[ 171.707324] x23: ffff00000504af50 x22: 0000000000000203 x21: 0000000000000000
[ 171.714518] x20: ffff000005c44a80 x19: ffff000005c457b8 x18: 0000000000000000
[ 171.721715] x17: 0000000000000000 x16: 0000000000000000 x15: 0000aaaae8887580
[ 171.728908] x14: 0000000000000000 x13: 0000000000000000 x12: ffff8000835ebc30
[ 171.736095] x11: ffff00000504af2a x10: ffff00008504af29 x9 : 0fffffffffffffff
[ 171.743286] x8 : ffff8000835ebbf8 x7 : 0000000000000000 x6 : 000000000000002a
[ 171.750479] x5 : ffff00000504af2e x4 : 0000000000000000 x3 : 0000000000000010
[ 171.757674] x2 : 0000000000000203 x1 : 0000000000000000 x0 : ffff8000835ebba0
[ 171.764871] Call trace:
[ 171.767342] pvr_fw_trace_mask_set+0x78/0x154 [powervr] (P)
[ 171.772984] simple_attr_write_xsigned.isra.0+0xe0/0x19c
[ 171.778341] simple_attr_write+0x18/0x24
[ 171.782296] debugfs_attr_write+0x50/0x98
[ 171.786341] full_proxy_write+0x6c/0xa8
[ 171.790208] vfs_write+0xd4/0x350
[ 171.793561] ksys_write+0x70/0x108
[ 171.796995] __arm64_sys_write+0x1c/0x28
[ 171.800952] invoke_syscall+0x48/0x10c
[ 171.804740] el0_svc_common.constprop.0+0x40/0xe0
[ 171.809487] do_el0_svc+0x1c/0x28
[ 171.812834] el0_svc+0x34/0x108
[ 171.816013] el0t_64_sync_handler+0xa0/0xe4
[ 171.820237] el0t_64_sync+0x198/0x19c
[ 171.823939] Code: 32000262 b90ac293 1a931056 9134e293 (b9000036)
[ 171.830073] ---[ end trace 0000000000000000 ]---
Fixes: a331631496a0 ("drm/imagination: Simplify module parameters")
Signed-off-by: Brajesh Gupta <brajesh.gupta@imgtec.com>
Reviewed-by: Alessio Belle <alessio.belle@imgtec.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260427-ftrace_fix-v3-1-e081530759a8@imgtec.com
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
Pull PCIe TSP update from Dan Williams:
"A small update for the TSM core. It is arguably a fix and coming in
late as I have been offline the past few weeks:
- Drop class_create() for the 'tsm' class"
* tag 'tsm-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/devsec/tsm:
virt: coco: change tsm_class to a const struct
On Raspberry Pi 3B, the VEC clock is used by the VideoCore firmware
display driver, which remains active until the vc4 driver loads and
sends NOTIFY_DISPLAY_DONE. If this clock is disabled during boot, a bus
lockup happens and the firmware becomes unresponsive, causing a complete
system lockup.
Mark the VEC clock with CLK_IGNORE_UNUSED so it survives the unused
clock disablement and remains available until the vc4 driver takes over
display management.
Fixes: 672299736af6 ("clk: bcm: rpi: Manage clock rate in prepare/unprepare callbacks")
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/r/5f0bec08-f458-4fba-8bf3-06817a100c4c@sirena.org.uk
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Link: https://patch.msgid.link/20260401111416.562279-2-mcanal@igalia.com
Tested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Brian Masney <bmasney@redhat.com> # Active contributor to clk
Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
My Outlook email address often sends emails from kernel devs to the junk
folder. Also, emails from some addresses (eg suse.de) are not received
at all. Update the email to my alternate Proton Mail address.
Signed-off-by: Aditya Garg <gargaditya08@proton.me>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patch.msgid.link/20260424175846.15103-1-gargaditya08@proton.me
Pull Kbuild fixes from Nicolas Schier:
- builddeb - avoid recompiles for non-cross-compiles
Avoid triggering complete rebuilds for non-cross-compile Debian
package builds by only triggering the rebuild of host tools for
actual cross-compile builds
- Never respect CONFIG_WERROR / W=e to fixdep
Avoid spurious rebuilds of fixdep w/ and w/o -Werror during a single
kbuild invocation by never respecting CONFIG_WERROR for fixdep
* tag 'kbuild-fixes-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
kbuild: Never respect CONFIG_WERROR / W=e to fixdep
kbuild: builddeb - avoid recompiles for non-cross-compiles
The class_create() call has been deprecated in favor of class_register()
as the driver core now allows for a struct class to be in read-only
memory. Change tsm_class to be a const struct class and drop the
class_create() call. Compile tested only.
Link: https://lore.kernel.org/all/2023040244-duffel-pushpin-f738@gregkh/
Changes with v1:
- Removed redundant int err variable.
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20260306183325.245254-1-jkoolstra@xs4all.nl
Signed-off-by: Dan Williams <djbw@kernel.org>
* clk-samsung:
clk: samsung: exynos850: Add APM-to-AP mailbox clock
dt-bindings: clock: exynos850: Add APM_AP MAILBOX clock
clk: samsung: Use %pe format to simplify
clk: samsung: pll: Fix possible truncation in a9fraco recalc rate
clk: samsung: exynosautov920: add block G3D clock support
dt-bindings: clock: exynosautov920: add G3D clock definitions
clk: samsung: gs101: harmonise symbol names (clock arrays)
clk: samsung: artpec-9: Add initial clock support for ARTPEC-9 SoC
clk: samsung: Add clock PLL support for ARTPEC-9 SoC
dt-bindings: clock: Add ARTPEC-9 clock controller
* clk-qcom: (67 commits)
clk: qcom: gcc: Add multiple global clock controller driver for Nord SoC
clk: qcom: rpmh: Add support for Nord rpmh clocks
clk: qcom: Add TCSR clock driver for Nord SoC
dt-bindings: clock: qcom: Add Nord Global Clock Controller
dt-bindings: clock: qcom-rpmhcc: Add support for Nord SoCs
dt-bindings: clock: qcom: Document the Nord SoC TCSR Clock Controller
clk: qcom: gcc-x1e80100: Keep GCC USB QTB clock always ON
clk: qcom: Constify list of critical CBCR registers
clk: qcom: Constify qcom_cc_driver_data
clk: qcom: videocc-glymur: Constify qcom_cc_desc
clk: qcom: Add a driver for SM8750 GPU clocks
dt-bindings: clock: qcom: Add SM8750 GPU clocks
clk: qcom: ipq-cmn-pll: Add IPQ8074 SoC support
dt-bindings: clock: qcom: Add CMN PLL support for IPQ8074
clk: qcom: ipq-cmn-pll: Add IPQ6018 SoC support
dt-bindings: clock: qcom: Add CMN PLL support for IPQ6018
clk: qcom: gdsc: Fix error path on registration of multiple pm subdomains
dt-bindings: clock: qcom: Add missing power-domains property
clk: qcom: gcc-eliza: Enable FORCE_MEM_CORE_ON for UFS AXI PHY clock
clk: qcom: dispcc-sc7180: Add missing MDSS resets
...
* clk-round:
clk: divider: remove divider_round_rate() and divider_round_rate_parent()
clk: divider: remove divider_ro_round_rate_parent()
clk: remove round_rate() clk ops
clk: composite: convert from round_rate() to determine_rate()
clk: test: remove references to clk_ops.round_rate
* clk-sai:
clk: fsl-sai: Add MCLK generation support
clk: fsl-sai: Extract clock setup into fsl_sai_clk_register()
dt-bindings: clock: fsl-sai: Document clock-cells = <1> support
clk: fsl-sai: Add i.MX8M support with 8 byte register offset
clk: fsl-sai: Sort the headers
dt-bindings: clock: fsl-sai: Document i.MX8M support
* clk-cleanup:
clk: visconti: pll: initialize clk_init_data to zero
clk: xgene: Fix mapping leak in xgene_pllclk_init()
clk: Simplify clk_is_match()
clk: baikal-t1: Remove not-going-to-be-supported code for Baikal SoC
clk: mvebu: armada-37xx-periph: fix __iomem casts in structure init
clk: qoriq: avoid format string warning
Fix a typo of "RGB332" in kerneldoc for the drm_crtc_fill_palette_332()
helper.
Fixes: 7ff61177b7116825 ("drm/color-mgmt: Prepare for RGB332 palettes")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patch.msgid.link/c413e45c8f752a532a4ff377f7a8b9eaab4a082a.1776757681.git.geert+renesas@glider.be
Pull power utility updates from Len Brown:
"x86_energy_perf_policy:
- Initial SoC Slider support
turbostat:
- Display HT siblings in cpu# order
- Add Module-ID column
- Print Core-ID and APIC-ID in hex
- Fix misc bugs"
* tag 'power-utilities-2026.04.25' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
tools/power x86_energy_perf_policy: Version 2026.04.25
tools/power x86_energy_perf_policy.8: Document SoC Slider Options
tools/power x86_energy_perf_policy: Enhances SoC Slider related checks
tools/power turbostat: v2026.04.21
tools/power turbostat: Process HT siblings in CPU order
tools/power turbostat: Show module_id column
tools/power turbostat: Print core_id and apic_id in hex
tools/power turbostat: Cleanup print helper functions
tools/power turbostat: Fix --cpu-set 1 regression on HT systems
tools/power turbostat: Fix --cpu-set 0 regression on HT systems
tools/power turbostat: Fix unrecognized option '-P'
tools/power turbostat: Fix AMD RAPL regression on big systems
tools/power/x86: Add SOC slider and platform profile support
The fixdep hostprog may be built multiple times during a single build.
Once during the configuration phase and later during the regular phase.
As only the regular build phase respects CONFIG_WERROR / W=e, the
compiler flags might change between the phases, leading to rebuilds.
Example, the rebuilds will happen twice on each invocation of the build:
$ make allyesconfig prepare
make[1]: Entering directory '/tmp/deleteme'
HOSTCC scripts/basic/fixdep
#
# No change to .config
#
HOSTCC scripts/basic/fixdep
DESCEND objtool
INSTALL libsubcmd_headers
make[1]: Leaving directory '/tmp/deleteme'
Fix the compilation flags used for scripts/basic/ before
scripts/Makefile.warn is evaluated to stop CONFIG_WERROR / W=e
influencing the fixdep build to avoid the spurious rebuilds.
Fixes: 7ded7d37e5f5 ("scripts/Makefile.extrawarn: Respect CONFIG_WERROR / W=e for hostprogs")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260422-kbuild-scripts-basic-werror-v1-1-8c6912ff22e0@weissschuh.net
Signed-off-by: Nicolas Schier <nsc@kernel.org>
* clk-tenstorrent:
clk: tenstorrent: Add Atlantis clock controller driver
reset: tenstorrent: Add reset controller for Atlantis
dt-bindings: clk: tenstorrent: Add tenstorrent,atlantis-prcm-rcpu
* clk-rockchip:
clk: rockchip: rk3568: Add PCIe pipe clock gates
clk: rockchip: Add clock controller for the RV1103B
dt-bindings: clock: rockchip: Add RV1103B CRU support
* clk-imx:
clk: imx8mq: Correct the CSI PHY sels
clk: vf610: Add support for the Ethernet switch clocks
dt-bindings: clock: vf610: Add definitions for MTIP L2 switch
dt-bindings: clock: vf610: Drop VF610_CLK_END define
clk: vf610: Move VF610_CLK_END define to clk-vf610 driver
clk: imx: imx8-acm: fix flags for acm clocks
clk: imx: imx6q: Fix device node reference leak in of_assigned_ldb_sels()
clk: imx: imx6q: Fix device node reference leak in pll6_bypassed()
clk: imx: fracn-gppll: Add 477.4MHz support
clk: imx: fracn-gppll: Add 333.333333 MHz support
clk: imx: pll14xx: Use unsigned format specifier
dt-bindings: clock: imx6q[ul]-clock: add optional clock enet[1]_ref_pad
* clk-allwinner:
clk: sunxi-ng: sun55i-a523-r: Add missing r-spi module clock