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 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 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
Clone this repository
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
Pull serial driver fixes from Greg KH:
"Here are three small serial driver fixes for 6.19-rc7 that resolve
some reported issues. They include:
- tty->port race condition fix for a reported problem
- qcom_geni serial driver fix
- 8250_pci serial driver fix
All of these have been in linux-next with no reported issues"
* tag 'tty-6.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: Fix not set tty->port race condition
serial: 8250_pci: Fix broken RS485 for F81504/508/512
serial: qcom_geni: Fix BT failure regression on RB2 platform
Pull i2c fix from Wolfram Sang:
- k1: drop wrong IRQF_ONESHOT from IRQ request to fix genirq warning
* tag 'i2c-for-6.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: spacemit: drop IRQF_ONESHOT flag from IRQ request
Revert commit bfc467db60b7 ("serial: remove redundant
tty_port_link_device()") because the tty_port_link_device() is not
redundant: the tty->port has to be confured before we call
uart_configure_port(), otherwise user-space can open console without TTY
linked to the driver.
This tty_port_link_device() was added explicitly to avoid this exact
issue in commit fb2b90014d78 ("tty: link tty and port before configuring
it as console"), so offending commit basically reverted the fix saying
it is redundant without addressing the actual race condition presented
there.
Reproducible always as tty->port warning on Qualcomm SoC with most of
devices disabled, so with very fast boot, and one serial device being
the console:
printk: legacy console [ttyMSM0] enabled
printk: legacy console [ttyMSM0] enabled
printk: legacy bootconsole [qcom_geni0] disabled
printk: legacy bootconsole [qcom_geni0] disabled
------------[ cut here ]------------
tty_init_dev: ttyMSM driver does not set tty->port. This would crash the kernel. Fix the driver!
WARNING: drivers/tty/tty_io.c:1414 at tty_init_dev.part.0+0x228/0x25c, CPU#2: systemd/1
Modules linked in: socinfo tcsrcc_eliza gcc_eliza sm3_ce fuse ipv6
CPU: 2 UID: 0 PID: 1 Comm: systemd Tainted: G S 6.19.0-rc4-next-20260108-00024-g2202f4d30aa8 #73 PREEMPT
Tainted: [S]=CPU_OUT_OF_SPEC
Hardware name: Qualcomm Technologies, Inc. Eliza (DT)
...
tty_init_dev.part.0 (drivers/tty/tty_io.c:1414 (discriminator 11)) (P)
tty_open (arch/arm64/include/asm/atomic_ll_sc.h:95 (discriminator 3) drivers/tty/tty_io.c:2073 (discriminator 3) drivers/tty/tty_io.c:2120 (discriminator 3))
chrdev_open (fs/char_dev.c:411)
do_dentry_open (fs/open.c:962)
vfs_open (fs/open.c:1094)
do_open (fs/namei.c:4634)
path_openat (fs/namei.c:4793)
do_filp_open (fs/namei.c:4820)
do_sys_openat2 (fs/open.c:1391 (discriminator 3))
...
Starting Network Name Resolution...
Apparently the flow with this small Yocto-based ramdisk user-space is:
driver (qcom_geni_serial.c): user-space:
============================ ===========
qcom_geni_serial_probe()
uart_add_one_port()
serial_core_register_port()
serial_core_add_one_port()
uart_configure_port()
register_console()
|
| open console
| ...
| tty_init_dev()
| driver->ports[idx] is NULL
|
tty_port_register_device_attr_serdev()
tty_port_link_device() <- set driver->ports[idx]
Fixes: bfc467db60b7 ("serial: remove redundant tty_port_link_device()")
Cc: stable@vger.kernel.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://patch.msgid.link/20260123072139.53293-2-krzysztof.kozlowski@oss.qualcomm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull input fixes from Dmitry Torokhov:
- a couple of quirks to i8042 to enable keyboard on a Asus and MECHREVO
laptops
* tag 'input-for-v6.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: i8042 - add quirks for MECHREVO Wujie 15X Pro
Input: i8042 - add quirk for ASUS Zenbook UX425QA_UM425QA
i2c-host-fixes for v6.19-rc7
k1: drop IRQF_ONESHOT from IRQ request to fix genirq warning.
Fintek F81504/508/512 can support both RTS_ON_SEND and RTS_AFTER_SEND,
but pci_fintek_rs485_supported only announces the former.
This makes it impossible to unset SER_RS485_RTS_ON_SEND from
userspace because of uart_sanitize_serial_rs485(). Some devices
with these chips need RTS low on TX, so they are effectively broken.
Fix this by announcing the support for SER_RS485_RTS_AFTER_SEND,
similar to commit 068d35a7be65 ("serial: sc16is7xx: announce support
for SER_RS485_RTS_ON_SEND").
Fixes: 4afeced55baa ("serial: core: fix sanitizing check for RTS settings")
Cc: stable <stable@kernel.org>
Signed-off-by: Marnix Rijnart <marnix.rijnart@iwell.eu>
Link: https://patch.msgid.link/20260112000931.61703-1-marnix.rijnart@iwell.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull RISC-V fixes from Paul Walmsley:
"The notable changes here are the three RISC-V timer compare register
update sequence patches. These only apply to RV32 systems and are
related to the 64-bit timer compare value being split across two
separate 32-bit registers.
We weren't using the appropriate three-write sequence, documented in
the RISC-V ISA specifications, to avoid spurious timer interrupts
during the update sequence; so, these patches now use the recommended
sequence.
This doesn't affect 64-bit RISC-V systems, since the timer compare
value fits inside a single register and can be updated with a single
write.
- Fix the RISC-V timer compare register update sequence on RV32
systems to use the recommended sequence in the RISC-V ISA manual
This avoids spurious interrupts during updates
- Add a dependence on the new CONFIG_CACHEMAINT_FOR_DMA Kconfig
symbol for Renesas and StarFive RISC-V SoCs
- Add a temporary workaround for a Clang compiler bug caused by using
asm_goto_output for get_user()
- Clarify our documentation to specifically state a particular ISA
specification version for a chapter number reference"
* tag 'riscv-for-linus-6.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: Add intermediate cast to 'unsigned long' in __get_user_asm
riscv: Use 64-bit variable for output in __get_user_asm
soc: renesas: Fix missing dependency on new CONFIG_CACHEMAINT_FOR_DMA
riscv: ERRATA_STARFIVE_JH7100: Fix missing dependency on new CONFIG_CACHEMAINT_FOR_DMA
riscv: suspend: Fix stimecmp update hazard on RV32
riscv: kvm: Fix vstimecmp update hazard on RV32
riscv: clocksource: Fix stimecmp update hazard on RV32
Documentation: riscv: uabi: Clarify ISA spec version for canonical order
The MECHREVO Wujie 15X Pro requires several i8042 quirks to function
correctly. Specifically, NOMUX, RESET_ALWAYS, NOLOOP, and NOPNP are
needed to ensure the keyboard and touchpad work reliably.
Signed-off-by: gongqi <550230171hxy@gmail.com>
Link: https://patch.msgid.link/20260122155501.376199-3-550230171hxy@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
In commit aef30c8d569c ("genirq: Warn about using IRQF_ONESHOT without a
threaded handler")[1], it will check IRQF_ONESHOT flag in IRQ request,
and gives a warning if there is no threaded handler. Drop this flag to
fix this warning.
Link: https://lore.kernel.org/r/20260112134013.eQWyReHR@linutronix.de/ [1]
Fixes: 5ea558473fa3 ("i2c: spacemit: add support for SpacemiT K1 SoC")
Signed-off-by: Yixun Lan <dlan@kernel.org>
Cc: <stable@vger.kernel.org> # v6.15+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260122-05-k1-i2c-irq-v1-1-9b8d94bbcd22@kernel.org
Commit 10904d725f6e ("serial: qcom-geni: Enable PM runtime for serial
driver") caused BT init to fail during bootup on the RB2 platform,
preventing proper BT initialization. However, BT works correctly after
bootup completes.
The issue occurs when runtime PM is enabled and uart_add_one_port() is
called before wakeup IRQ setup. The uart_add_one_port() call activates
the device through runtime PM, which configures GPIOs to the "qup_x"
pinmux function during runtime resume. When wakeup IRQ registration
happens afterward using dev_pm_set_dedicated_wake_irq(), these GPIOs
are reset back to the "gpio" pinmux function, which impacts the RX GPIO
and leads to Bluetooth failures.
Fix this by ensuring wakeup IRQ setup is completed before calling
uart_add_one_port() to prevent the pinmux function conflict.
Fixes: 10904d725f6e ("serial: qcom-geni: Enable PM runtime for serial driver")
Reported-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Closes: https://lore.kernel.org/all/20251110101043.2108414-4-praveen.talari@oss.qualcomm.com/
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
Link: https://patch.msgid.link/20260108041006.1874757-1-praveen.talari@oss.qualcomm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull NTB fix from Jon Mason:
"Bug fix for uninitialized mutex in ntb transport"
* tag 'ntb-6.19-bugfixes' of https://github.com/jonmason/ntb:
ntb: transport: Fix uninitialized mutex
After commit bdce162f2e57 ("riscv: Use 64-bit variable for output in
__get_user_asm"), there is a warning when building for 32-bit RISC-V:
In file included from include/linux/uaccess.h:13,
from include/linux/sched/task.h:13,
from include/linux/sched/signal.h:9,
from include/linux/rcuwait.h:6,
from include/linux/mm.h:36,
from include/linux/migrate.h:5,
from mm/migrate.c:16:
mm/migrate.c: In function 'do_pages_move':
arch/riscv/include/asm/uaccess.h:115:15: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
115 | (x) = (__typeof__(x))__tmp; \
| ^
arch/riscv/include/asm/uaccess.h:198:17: note: in expansion of macro '__get_user_asm'
198 | __get_user_asm("lb", (x), __gu_ptr, label); \
| ^~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:218:9: note: in expansion of macro '__get_user_nocheck'
218 | __get_user_nocheck(x, ptr, __gu_failed); \
| ^~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:255:9: note: in expansion of macro '__get_user_error'
255 | __get_user_error(__gu_val, __gu_ptr, __gu_err); \
| ^~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:285:17: note: in expansion of macro '__get_user'
285 | __get_user((x), __p) : \
| ^~~~~~~~~~
mm/migrate.c:2358:29: note: in expansion of macro 'get_user'
2358 | if (get_user(p, pages + i))
| ^~~~~~~~
Add an intermediate cast to 'unsigned long', which is guaranteed to be the same
width as a pointer, before the cast to the type of the output variable to clear
up the warning.
Fixes: bdce162f2e57 ("riscv: Use 64-bit variable for output in __get_user_asm")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202601210526.OT45dlOZ-lkp@intel.com/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260121-riscv-fix-int-to-pointer-cast-v1-1-b83eebe57c76@kernel.org
Signed-off-by: Paul Walmsley <pjw@kernel.org>
The ASUS Zenbook UX425QA_UM425QA fails to initialize the keyboard after
a cold boot.
A quirk already exists for "ZenBook UX425", but some Zenbooks report
"Zenbook" with a lowercase 'b'. Since DMI matching is case-sensitive,
the existing quirk is not applied to these "extra special" Zenbooks.
Testing confirms that this model needs the same quirks as the ZenBook
UX425 variants.
Signed-off-by: feng <alec.jiang@gmail.com>
Link: https://patch.msgid.link/20260122013957.11184-1-alec.jiang@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Pull landlock fixes from Mickaël Salaün:
"This fixes TCP handling, tests, documentation, non-audit elided code,
and minor cosmetic changes"
* tag 'landlock-6.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux:
landlock: Clarify documentation for the IOCTL access right
selftests/landlock: Properly close a file descriptor
landlock: Improve the comment for domain_is_scoped
selftests/landlock: Use scoped_base_variants.h for ptrace_test
selftests/landlock: Fix missing semicolon
selftests/landlock: Fix typo in fs_test
landlock: Optimize stack usage when !CONFIG_AUDIT
landlock: Fix spelling
landlock: Clean up hook_ptrace_access_check()
landlock: Improve erratum documentation
landlock: Remove useless include
landlock: Fix wrong type usage
selftests/landlock: NULL-terminate unix pathname addresses
selftests/landlock: Remove invalid unix socket bind()
selftests/landlock: Add missing connect(minimal AF_UNSPEC) test
selftests/landlock: Fix TCP bind(AF_UNSPEC) test case
landlock: Fix TCP handling of short AF_UNSPEC addresses
landlock: Fix formatting
Pull nfsd fixes from Chuck Lever:
"A set of NFSD fixes that arrived just a bit late for the 6.19 merge
window.
Regression fixes:
- Mark variable __maybe_unused to avoid W=1 build break
Stable fixes:
- NFSv4 file creation neglects setting ACL
- Clear TIME_DELEG in the suppattr_exclcreat bitmap
- Clear SECLABEL in the suppattr_exclcreat bitmap
- Fix memory leak in nfsd_create_serv error paths
- Bound check rq_pages index in inline path
- Return 0 on success from svc_rdma_copy_inline_range
- Use rc_pageoff for memcpy byte offset
- Avoid NULL deref on zero length gss_token in gss_read_proxy_verf"
* tag 'nfsd-6.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
NFSD: NFSv4 file creation neglects setting ACL
NFSD: Clear TIME_DELEG in the suppattr_exclcreat bitmap
NFSD: Clear SECLABEL in the suppattr_exclcreat bitmap
nfsd: fix memory leak in nfsd_create_serv error paths
nfsd: Mark variable __maybe_unused to avoid W=1 build break
svcrdma: bound check rq_pages index in inline path
svcrdma: return 0 on success from svc_rdma_copy_inline_range
svcrdma: use rc_pageoff for memcpy byte offset
SUNRPC: svcauth_gss: avoid NULL deref on zero length gss_token in gss_read_proxy_verf