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
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Pull SCSI fixes from James Bottomley:
"The only core fix is in doc; all the others are in drivers, with the
biggest impacts in libsas being the rollback on error handling and in
ufs coming from a couple of error handling fixes, one causing a crash
if it's activated before scanning and the other fixing W-LUN
resumption"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: ufs: qcom: Fix confusing cleanup.h syntax
scsi: libsas: Add rollback handling when an error occurs
scsi: device_handler: Return error pointer in scsi_dh_attached_handler_name()
scsi: ufs: core: Fix a deadlock in the frequency scaling code
scsi: ufs: core: Fix an error handler crash
scsi: Revert "scsi: libsas: Fix exp-attached device scan after probe failure scanned in again after probe failed"
scsi: ufs: core: Fix RPMB link error by reversing Kconfig dependencies
scsi: qla4xxx: Use time conversion macros
scsi: qla2xxx: Enable/disable IRQD_NO_BALANCING during reset
scsi: ipr: Enable/disable IRQD_NO_BALANCING during reset
scsi: imm: Fix use-after-free bug caused by unfinished delayed work
scsi: target: sbp: Remove KMSG_COMPONENT macro
scsi: core: Correct documentation for scsi_device_quiesce()
scsi: mpi3mr: Prevent duplicate SAS/SATA device entries in channel 1
scsi: target: Reset t_task_cdb pointer in error case
scsi: ufs: core: Fix EH failure after W-LUN resume error
Pull ceph updates from Ilya Dryomov:
"We have a patch that adds an initial set of tracepoints to the MDS
client from Max, a fix that hardens osdmap parsing code from myself
(marked for stable) and a few assorted fixups"
* tag 'ceph-for-6.19-rc1' of https://github.com/ceph/ceph-client:
rbd: stop selecting CRC32, CRYPTO, and CRYPTO_AES
ceph: stop selecting CRC32, CRYPTO, and CRYPTO_AES
libceph: make decode_pool() more resilient against corrupted osdmaps
libceph: Amend checking to fix `make W=1` build breakage
ceph: Amend checking to fix `make W=1` build breakage
ceph: add trace points to the MDS client
libceph: fix log output race condition in OSD client
Initializing automatic __free variables to NULL without need (e.g.
branches with different allocations), followed by actual allocation is
in contrary to explicit coding rules guiding cleanup.h:
"Given that the "__free(...) = NULL" pattern for variables defined at
the top of the function poses this potential interdependency problem the
recommendation is to always define and assign variables in one statement
and not group variable definitions at the top of the function when
__free() is used."
Code does not have a bug, but is less readable and uses discouraged
coding practice, so fix that by moving declaration to the place of
assignment.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20251208020807.5043-2-krzysztof.kozlowski@oss.qualcomm.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Pull tomoyo update from Tetsuo Handa:
"Trivial optimization"
* tag 'tomoyo-pr-20251212' of git://git.code.sf.net/p/tomoyo/tomoyo:
tomoyo: Use local kmap in tomoyo_dump_page()
None of the RBD code directly requires CRC32, CRYPTO, or CRYPTO_AES.
These options are needed by CEPH_LIB code and they are selected there
directly.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Dongsheng Yang <dongsheng.yang@linux.dev>
In sas_register_phys(), if an error is triggered in the loop process, we
need to roll back the resources that have already been requested.
Add sas_unregister_phys() when an error occurs in sas_register_ha().
[mkp: a few coding style tweaks and address John's comment]
Signed-off-by: Chaohai Chen <wdhh6@aliyun.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://patch.msgid.link/20251206060616.69216-1-wdhh6@aliyun.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Pull CPU hotplug fix from Ingo Molnar:
- Fix CPU hotplug callbacks to disable interrupts on UP kernels
* tag 'smp-urgent-2025-12-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu: Make atomic hotplug callbacks run with interrupts disabled on UP
Replace the now deprecated kmap_atomic() with kmap_local_page().
The memcpy does not need atomic semantics, and the removed comment
is now stale - this patch now makes it in sync again. Last but not
least, highmem is going to be removed[0].
Link: https://lore.kernel.org/all/4ff89b72-03ff-4447-9d21-dd6a5fe1550f@app.fastmail.com/ [0]
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
None of the CEPH_FS code directly requires CRC32, CRYPTO, or CRYPTO_AES.
These options do get selected indirectly anyway via CEPH_LIB, which does
need them, but there is no need for CEPH_FS to select them too.
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
If scsi_dh_attached_handler_name() fails to allocate the handler name,
dm-multipath (its only caller) assumes there is no attached device
handler, and sets the device up incorrectly. Return an error pointer
instead, so multipath can distinguish between failure, success where
there is no attached device handler, or when the path device is not a
SCSI device at all.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Link: https://patch.msgid.link/20251206010015.1595225-1-bmarzins@redhat.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Pull perf event fixes from Ingo Molnar:
- Fix NULL pointer dereference crash in the Intel PMU driver
- Fix missing read event generation on task exit
- Fix AMD uncore driver init error handling
- Fix whitespace noise
* tag 'perf-urgent-2025-12-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Fix NULL event dereference crash in handle_pmi_common()
perf/core: Fix missing read event generation on task exit
perf/x86/amd/uncore: Fix the return value of amd_uncore_df_event_init() on error
perf/uprobes: Remove <space><Tab> whitespace noise
On SMP systems the CPU hotplug callbacks in the "starting" range are
invoked while the CPU is brought up and interrupts are still
disabled. Callbacks which are added later are invoked via the
hotplug-thread on the target CPU and interrupts are explicitly disabled.
In the UP case callbacks which are added later are invoked directly without
the thread indirection. This is in principle okay since there is just one
CPU but those callbacks are invoked with interrupt disabled code. That's
incorrect as those callbacks assume interrupt disabled context.
Disable interrupts before invoking the callbacks on UP if the state is
atomic and interrupts are expected to be disabled. The "save" part is
required because this is also invoked early in the boot process while
interrupts are disabled and must not be enabled prematurely.
Fixes: 06ddd17521bf1 ("sched/smp: Always define is_percpu_thread() and scheduler_ipi()")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251127144723.ev9DuXXR@linutronix.de
If the osdmap is (maliciously) corrupted such that the encoded length
of ceph_pg_pool envelope is less than what is expected for a particular
encoding version, out-of-bounds reads may ensue because the only bounds
check that is there is based on that length value.
This patch adds explicit bounds checks for each field that is decoded
or skipped.
Cc: stable@vger.kernel.org
Reported-by: ziming zhang <ezrakiez@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Tested-by: ziming zhang <ezrakiez@gmail.com>
Commit 08b12cda6c44 ("scsi: ufs: core: Switch to scsi_get_internal_cmd()")
accidentally introduced a deadlock in the frequency scaling code.
ufshcd_clock_scaling_unprepare() may submit a device management command
while SCSI command processing is blocked. The deadlock was introduced by
using the SCSI core for submitting device management commands
(scsi_get_internal_cmd() + blk_execute_rq()). Fix this deadlock by calling
blk_mq_unquiesce_tagset() before any device management commands are
submitted by ufshcd_clock_scaling_unprepare().
Fixes: 08b12cda6c44 ("scsi: ufs: core: Switch to scsi_get_internal_cmd()")
Reported-by: Manivannan Sadhasivam <mani@kernel.org>
Reported-by: Roger Shimizu <rosh@debian.org>
Closes: https://lore.kernel.org/linux-scsi/ehorjaflathzab5oekx2nae2zss5vi2r36yqkqsfjb2fgsifz2@yk3us5g3igow/
Tested-by: Roger Shimizu <rosh@debian.org>
Cc: Nitin Rawat <nitin.rawat@oss.qualcomm.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Reviewed-by: Nitin Rawat <nitin.rawat@oss.qualcomm.com>
Tested-by: Alexey Klimov <alexey.klimov@linaro.org> # RB5 board
Link: https://patch.msgid.link/20251204181548.1006696-1-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Pull irq fixes from Ingo Molnar:
- Fix error code in the irqchip/mchp-eic driver
- Fix setup_percpu_irq() affinity assumptions
- Remove the unused irq_domain_add_tree() function
* tag 'irq-urgent-2025-12-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/mchp-eic: Fix error code in mchp_eic_domain_alloc()
irqdomain: Delete irq_domain_add_tree()
genirq: Allow NULL affinity for setup_percpu_irq()