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 soundwire fix from Vinod Koul:
- Single off-by-one fix for allocating slave id
* tag 'soundwire-6.19-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/soundwire:
soundwire: bus: fix off-by-one when allocating slave IDs
Pull USB fixes from Greg KH:
"Here are some small USB fixes and new device ids for 6.19-rc6
Included in here are:
- new usb-serial device ids
- dwc3-apple driver fixes to get things working properly on that
hardware platform
- ohci/uhci platfrom driver module soft-deps with ehci to remove a
runtime warning that sometimes shows up on some platforms.
- quirk for broken devices that can not handle reading the BOS
descriptor from them without going crazy.
- usb-serial driver fixes
- xhci driver fixes
- usb gadget driver fixes
All of these except for the last xhci fix has been in linux-next for a
while. The xhci fix has been reported by others to solve the issue for
them, so should be ok"
* tag 'usb-6.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
xhci: sideband: don't dereference freed ring when removing sideband endpoint
usb: gadget: uvc: retry vb2_reqbufs() with vb_vmalloc_memops if use_sg fail
usb: gadget: uvc: return error from uvcg_queue_init()
usb: gadget: uvc: fix interval_duration calculation
usb: gadget: uvc: fix req_payload_size calculation
usb: dwc3: apple: Ignore USB role switches to the active role
usb: host: xhci-tegra: Use platform_get_irq_optional() for wake IRQs
USB: OHCI/UHCI: Add soft dependencies on ehci_platform
usb: dwc3: apple: Set USB2 PHY mode before dwc3 init
USB: serial: f81232: fix incomplete serial port generation
USB: serial: ftdi_sio: add support for PICAXE AXE027 cable
USB: serial: option: add Telit LE910 MBIM composition
usb: core: add USB_QUIRK_NO_BOS for devices that hang on BOS descriptor
dt-bindings: usb: qcom,dwc3: Correct MSM8994 interrupts
dt-bindings: usb: qcom,dwc3: Correct IPQ5018 interrupts
tcpm: allow looking for role_sw device in the main node
usb: dwc3: Check for USB4 IP_NAME
ida_alloc_max() interprets its max argument as inclusive.
Using SDW_FW_MAX_DEVICES(16) therefore allows an ID of 16 to be
allocated, but the IRQ domain created for the bus is sized for IDs
0-15. If 16 is returned, irq_create_mapping() fails and the driver
ends up with an invalid IRQ mapping.
Limit the allocation to 0-15 by passing SDW_FW_MAX_DEVICES - 1.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202512240450.hlDH3nCs-lkp@intel.com/
Fixes: aab12022b076 ("soundwire: bus: Add internal slave ID and use for IRQs")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://patch.msgid.link/20260110201959.2523024-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Pull i2c fixes from Wolfram Sang:
- riic, imx-lpi2c: suspend/resume fixes
- qcom-geni: DMA handling fix
- iproc: correct DT binding description
* tag 'i2c-for-6.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: imx-lpi2c: change to PIO mode in system-wide suspend/resume progress
i2c: qcom-geni: make sure I2C hub controllers can't use SE DMA
i2c: riic: Move suspend handling to NOIRQ phase
dt-bindings: i2c: brcm,iproc-i2c: Allow 2 reg entries for brcm,iproc-nic-i2c
xhci_sideband_remove_endpoint() incorrecly assumes that the endpoint is
running and has a valid transfer ring.
Lianqin reported a crash during suspend/wake-up stress testing, and
found the cause to be dereferencing a non-existing transfer ring
'ep->ring' during xhci_sideband_remove_endpoint().
The endpoint and its ring may be in unknown state if this function
is called after xHCI was reinitialized in resume (lost power), or if
device is being re-enumerated, disconnected or endpoint already dropped.
Fix this by both removing unnecessary ring access, and by checking
ep->ring exists before dereferencing it. Also make sure endpoint is
running before attempting to stop it.
Remove the xhci_initialize_ring_info() call during sideband endpoint
removal as is it only initializes ring structure enqueue, dequeue and
cycle state values to their starting values without changing actual
hardware enqueue, dequeue and cycle state. Leaving them out of sync
is worse than leaving it as it is. The endpoint will get freed in after
this in most usecases.
If the (audio) class driver want's to reuse the endpoint after offload
then it is up to the class driver to ensure endpoint is properly set up.
Reported-by: 胡连勤 <hulianqin@vivo.com>
Closes: https://lore.kernel.org/linux-usb/TYUPR06MB6217B105B059A7730C4F6EC8D2B9A@TYUPR06MB6217.apcprd06.prod.outlook.com/
Tested-by: 胡连勤 <hulianqin@vivo.com>
Fixes: de66754e9f80 ("xhci: sideband: add initial api to register a secondary interrupter entity")
Cc: stable@vger.kernel.org
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20260115233758.364097-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull EDAC fixes from Borislav Petkov:
"Make sure the memory-mapped memory controller registers BAR gets
unmapped when the driver memory allocation fails
Fix that in both x38 and i3200 EDAC drivers as former has copied the
bug from the latter, it looks like"
* tag 'edac_urgent_for_v6.19_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
EDAC/x38: Fix a resource leak in x38_probe1()
EDAC/i3200: Fix a resource leak in i3200_probe1()
EDMA resumes early and suspends late in the system power transition
sequence, while LPI2C enters the NOIRQ stage for both suspend and resume.
This means LPI2C resources become available before EDMA is fully resumed.
Once IRQs are enabled, a slave device may immediately trigger an LPI2C
transfer. If the transfer length meets DMA requirements, the driver will
attempt to use EDMA even though EDMA may still be unavailable.
This timing gap can lead to transfer failures. To prevent this, force
LPI2C to use PIO mode during system-wide suspend and resume transitions.
This reduces dependency on EDMA and avoids using an unready DMA resource.
Fixes: a09c8b3f9047 ("i2c: imx-lpi2c: add eDMA mode support for LPI2C")
Signed-off-by: Carlos Song <carlos.song@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Johan writes:
USB serial fix for 6.19-rc6
Here's a fix for an f81232 enumeration issue that could prevent some
ports from being enabled (e.g. during driver rebind).
Included are also some new device ids.
All have been in linux-next with no reported issues.
* tag 'usb-serial-6.19-rc6' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial:
USB: serial: f81232: fix incomplete serial port generation
USB: serial: ftdi_sio: add support for PICAXE AXE027 cable
USB: serial: option: add Telit LE910 MBIM composition
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 misc x86 fixes from Ingo Molnar:
- Fix resctrl initialization on Hygon CPUs
- Fix resctrl memory bandwidth counters on Hygon CPUs
- Fix x86 self-tests build bug
* tag 'x86-urgent-2026-01-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
selftests/x86: Add selftests include path for kselftest.h after centralization
x86/resctrl: Fix memory bandwidth counter width for Hygon
x86/resctrl: Add missing resctrl initialization for Hygon
If edac_mc_alloc() fails, also unmap the window.
[ bp: Use separate labels, turning it into the classic unwind pattern. ]
Fixes: df8bc08c192f ("edac x38: new MC driver module")
Signed-off-by: Haoxiang Li <lihaoxiang@isrc.iscas.ac.cn>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251223124350.1496325-1-lihaoxiang@isrc.iscas.ac.cn
The I2C Hub controller is a simpler GENI I2C variant that doesn't
support DMA at all, add a no_dma flag to make sure it nevers selects
the SE DMA mode with mappable 32bytes long transfers.
Fixes: cacd9643eca7 ("i2c: qcom-geni: add support for I2C Master Hub variant")
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Mukesh Kumar Savaliya <mukesh.savaliya@oss.qualcomm.com>>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Based on the reality[1][2] that vb2_dma_sg_alloc() can't alloc buffer with
device DMA limits, those device will always get below error: "swiotlb
buffer is full (sz: 393216 bytes), total 65536 (slots), used 2358 (slots)"
and the uvc gadget function can't work at all.
The videobuf2-dma-sg.c driver doesn't has a formal improve about this issue
till now. For UVC gadget, the videobuf2 subsystem doesn't do dma_map() on
vmalloc returned big buffer when allocate the video buffers, however, it do
it for dma_sg returned buffer. So the issue happens for vb2_dma_sg_alloc().
To workaround the issue, lets retry vb2_reqbufs() with
vb_vmalloc_memops if it fails to allocate buffer with vb2_dma_sg_memops.
If use vmalloced buffer, UVC gadget will allocate some small buffers for
each usb_request to do dma transfer, then uvc driver will memcopy data
from big buffer to small buffer.
Link[1]: https://lore.kernel.org/linux-media/20230828075420.2009568-1-anle.pan@nxp.com/
Link[2]: https://lore.kernel.org/linux-media/20230914145812.12851-1-hui.fang@nxp.com/
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260113-uvc-gadget-fix-patch-v2-4-62950ef5bcb5@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Fintek F81532A/534A/535/536 family relies on the
F81534A_CTRL_CMD_ENABLE_PORT (116h) register during initialization to
both determine serial port status and control port creation. If the
driver experiences fast load/unload cycles, the device state may becomes
unstable, resulting in the incomplete generation of serial ports.
Performing a dummy read operation on the register prior to the initial
write command resolves the issue. This clears the device's stale internal
state. Subsequent write operations will correctly generate all serial
ports.
This patch also removes the retry loop in f81534a_ctrl_set_register()
because the stale state has been fixed.
Tested on: HygonDM1SLT(Hygon C86 3250 8-core Processor)
Signed-off-by: Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw>
Signed-off-by: Johan Hovold <johan@kernel.org>
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