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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Fix the reference to 'boot-image-header.rst', which was moved to
'Documentation/arch/riscv/' in commit 'ed843ae947f8'
("docs: move riscv under arch").
Signed-off-by: Soham Metha <sohammetha01@gmail.com>
Link: https://patch.msgid.link/20251203194355.63265-1-sohammetha01@gmail.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
These marcos are not used after commit b5b4287accd7 ("riscv: mm: Use
hint address in mmap if available"). Cleanup VA_USER_XXX definitions
in asm/pgtable.h.
Fixes: b5b4287accd7 ("riscv: mm: Use hint address in mmap if available")
Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@kernel.org>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://patch.msgid.link/20251201005850.702569-1-guoren@kernel.org
Signed-off-by: Paul Walmsley <pjw@kernel.org>
The Zk extension is a bundle consisting of Zkn, Zkr, and Zkt. The Zkn
extension itself is a bundle consisting of Zbkb, Zbkc, Zbkx, Zknd, Zkne,
and Zknh.
The current implementation of riscv_zk_bundled_exts manually listed
the dependencies but missed RISCV_ISA_EXT_ZKNH.
Fix this by introducing a RISCV_ISA_EXT_ZKN macro that lists the Zkn
components and using it in both riscv_zk_bundled_exts and
riscv_zkn_bundled_exts.
This adds the missing Zknh extension to Zk and reduces code duplication.
Fixes: 0d8295ed975b ("riscv: add ISA extension parsing for scalar crypto")
Link: https://patch.msgid.link/20231114141256.126749-4-cleger@rivosinc.com/
Signed-off-by: Guodong Xu <guodong@riscstar.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Link: https://patch.msgid.link/20251223-zk-missing-zknh-v1-1-b627c990ee1a@riscstar.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Clang misinterprets the placement of test_kprobes_addresses and
test_kprobes_functions arrays when they are not explicitly assigned
to a data section. This can lead to kmalloc_array() allocation
errors and KUnit failures.
When testing the Clang-compiled code in QEMU, this warning was emitted:
WARNING: CPU: 1 PID: 3000 at mm/page_alloc.c:5159 __alloc_frozen_pages_noprof+0xe6/0x2fc mm/page_alloc.c:5159
Further investigation revealed that the test_kprobes_addresses array
appeared to have over 100,000 elements, including invalid addresses;
whereas, according to test-kprobes-asm.S, test_kprobes_addresses
should only have 25 elements.
When compiling the kernel with GCC, the kernel boots correctly.
This patch fixes the issue by adding .section .rodata to explicitly
place arrays in the read-only data segment.
For detailed debug and analysis, see:
https://github.com/j1akai/temp/blob/main/20251113/readme.md
v1 -> v2:
- Drop changes to .align, and .globl.
Signed-off-by: Jiakai Xu <xujiakai2025@iscas.ac.cn>
Signed-off-by: Jiakai Xu <jiakaiPeanut@gmail.com>
Link: https://patch.msgid.link/738dd4e2.ff73.19a7cd7b4d5.Coremail.xujiakai2025@iscas.ac.cn
Link: https://github.com/llvm/llvm-project/issues/168308
Link: https://patch.msgid.link/20251226032317.1523764-1-jiakaiPeanut@gmail.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
The syscall number is a user-controlled value used to index into the
syscall table. Use array_index_nospec() to clamp this value after the
bounds check to prevent speculative out-of-bounds access and subsequent
data leakage via cache side channels.
Signed-off-by: Lukas Gerlach <lukas.gerlach@cispa.de>
Link: https://patch.msgid.link/20251218191332.35849-3-lukas.gerlach@cispa.de
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Since commit 4b47a3aefb29 ("kbuild: Restore pattern to avoid stripping
.rela.dyn from vmlinux") vmlinux has .rel*.dyn preserved. Therefore, use
vmlinux to produce Image, not vmlinux.unstripped.
Doing so fixes booting a RELOCATABLE=y Image with kexec. The problem is
caused by this chain of events:
- Since commit 3e86e4d74c04 ("kbuild: keep .modinfo section in
vmlinux.unstripped"), vmlinux.unstripped gets a .modinfo section.
- The .modinfo section has SHF_ALLOC, so it ends up in Image, at the end
of it.
- The Image header's image_size field does not expect to include
.modinfo and does not account for it, since it should not be in Image.
- If .modinfo is large enough, the file size of Image ends up larger
than image_size, which eventually leads to it failing
sanity_check_segment_list().
Using vmlinux instead of vmlinux.unstripped means that the unexpected
.modinfo section is gone from Image, fixing the file size problem.
Cc: stable@vger.kernel.org
Fixes: 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped")
Signed-off-by: Vivian Wang <wangruikang@iscas.ac.cn>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Han Gao <gaohan@iscas.ac.cn>
Link: https://patch.msgid.link/20251230-riscv-vmlinux-not-unstripped-v1-1-15f49df880df@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Pull USB fixes from Greg KH:
"Here are some small USB fixes, and bunch of reverts for 6.19-rc3.
Included in here are:
- reverts of some typec ucsi driver changes that had a lot of
regression reports after -rc1. Let's just revert it all for now and
it will come back in a way that is better tested.
- other typec bugfixes
- usb-storage quirk fixups
- dwc3 driver fix
- other minor USB fixes for reported problems.
All of these have passed 0-day testing and individual testing"
* tag 'usb-6.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (22 commits)
Revert "usb: typec: ucsi: Update UCSI structure to have message in and message out fields"
Revert "usb: typec: ucsi: Add support for message out data structure"
Revert "usb: typec: ucsi: Enable debugfs for message_out data structure"
Revert "usb: typec: ucsi: Add support for SET_PDOS command"
Revert "usb: typec: ucsi: Fix null pointer dereference in ucsi_sync_control_common"
Revert "usb: typec: ucsi: Get connector status after enable notifications"
usb: ohci-nxp: clean up probe error labels
usb: gadget: lpc32xx_udc: clean up probe error labels
usb: ohci-nxp: fix device leak on probe failure
usb: phy: isp1301: fix non-OF device reference imbalance
usb: gadget: lpc32xx_udc: fix clock imbalance in error path
usb: typec: ucsi: Get connector status after enable notifications
usb: usb-storage: Maintain minimal modifications to the bcdDevice range.
usb: dwc3: of-simple: fix clock resource leak in dwc3_of_simple_probe
usb: typec: ucsi: Fix null pointer dereference in ucsi_sync_control_common
USB: lpc32xx_udc: Fix error handling in probe
usb: typec: altmodes/displayport: Drop the device reference in dp_altmode_probe()
usb: phy: fsl-usb: Fix use-after-free in delayed work during device removal
usb: renesas_usbhs: Fix a resource leak in usbhs_pipe_malloc()
usb: typec: ucsi: huawei-gaokin: add DRM dependency
...
Pull serial driver fixes from Greg KH:
"Here are some small serial driver fixes for some reported issues.
Included in here are:
- serial sysfs fwnode fix that was much reported
- sh-sci driver fix
- serial device init bugfix
- 8250 bugfix
- xilinx_uartps bugfix
All of these have passed 0-day testing and individual testing"
* tag 'tty-6.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: xilinx_uartps: fix rs485 delay_rts_after_send
serial: sh-sci: Check that the DMA cookie is valid
serial: core: Fix serial device initialization
serial: 8250: longson: Fix NULL vs IS_ERR() bug in probe
serial: core: Restore sysfs fwnode information
Johan Hovold <johan@kernel.org> says:
The new buffer management code has not been tested or reviewed properly
and breaks boot of machines like the Lenovo ThinkPad X13s.
Fixing this will require designing a proper interface for managing these
transactions, something which most likely involves reverting most of the
offending commit anyway.
Revert the broken code to fix the regression and let Intel come up with
a properly tested implementation for a later kernel.
Link: https://lore.kernel.org/r/20251222152204.2846-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull firewire fix from Takashi Sakamoto:
"A fix for PCI driver for Texas Instruments PCILyx series.
The driver had a bug where it allocated a DMA-coherent buffer of 16 KB
but released it using PAGE_SIZE. This disproportion was reported in
2020, but the fix was never merged. It is finally resolved"
* tag 'firewire-fixes-6.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
firewire: nosy: Fix dma_free_coherent() size
RTS line control with delay should be triggered when there is no more
bytes in kfifo and hardware buffer is empty. Without this patch RTS
control is scheduled right after feeding hardware buffer and this is too
early.
RTS line may change state before hardware buffer is empty.
With this patch delayed RTS state change is triggered when function
cdns_uart_handle_tx is called from cdns_uart_isr on
CDNS_UART_IXR_TXEMPTY exactly when hardware completed transmission
Fixes: fccc9d9233f9 ("tty: serial: uartps: Add rs485 support to uartps driver")
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20251221103221.1971125-1-jakub.turek@elsta.tech
Signed-off-by: Jakub Turek <jakub.turek@elsta.tech>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 14ad4c10d5bdd413ff9a914260e89b5f54b7a2c7.
The originally offending commit will be reverted instead of this fix up
at this point in time, so revert this fix.
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: stable <stable@kernel.org>
Cc: Johan Hovold <johan@kernel.org>
Fixes: 14ad4c10d5bd ("usb: typec: ucsi: Fix null pointer dereference in ucsi_sync_control_common")
Link: https://lore.kernel.org/r/20251222152204.2846-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 3e082978c33151d576694deac8abde021ea669a8.
The new buffer management code has not been tested or reviewed properly
and breaks boot of machines like the Lenovo ThinkPad X13s:
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000000
CPU: 0 UID: 0 PID: 813 Comm: kworker/0:3 Not tainted 6.19.0-rc2 #26 PREEMPT
Hardware name: LENOVO 21BYZ9SRUS/21BYZ9SRUS, BIOS N3HET87W (1.59 ) 12/05/2023
Workqueue: events ucsi_handle_connector_change [typec_ucsi]
Call trace:
ucsi_sync_control_common+0xe4/0x1ec [typec_ucsi] (P)
ucsi_run_command+0xcc/0x194 [typec_ucsi]
ucsi_send_command_common+0x84/0x2a0 [typec_ucsi]
ucsi_get_connector_status+0x48/0x78 [typec_ucsi]
ucsi_handle_connector_change+0x5c/0x4f4 [typec_ucsi]
process_one_work+0x208/0x60c
worker_thread+0x244/0x388
The new code completely ignores concurrency so that the message length
can be updated while a transaction is ongoing. In the above case, the
length ends up being modified by another thread while processing an ack
so that the NULL cci pointer is dereferenced.
Fixing this will require designing a proper interface for managing these
transactions, something which most likely involves reverting most of the
offending commit anyway.
Revert the broken code to fix the regression and let Intel come up with
a properly tested implementation for a later kernel.
Fixes: 3e082978c331 ("usb: typec: ucsi: Update UCSI structure to have message in and message out fields")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20251222152204.2846-5-johan@kernel.org
Pull RISC-V updates from Paul Walmsley:
"Nothing exotic here; these are the cleanup and new ISA extension
probing patches (not including CFI):
- Add probing and userspace reporting support for the standard RISC-V
ISA extensions Zilsd and Zclsd, which implement load/store dual
instructions on RV32
- Abstract the register saving code in setup_sigcontext() so it can
be used for stateful RISC-V ISA extensions beyond the vector
extension
- Add the SBI extension ID and some initial data structure
definitions for the RISC-V standard SBI debug trigger extension
- Clean up some code slightly: change some page table functions to
avoid atomic operations oinn !SMP and to avoid unnecessary casts to
atomic_long_t; and use the existing RISCV_FULL_BARRIER macro in
place of some open-coded 'fence rw,rw' instructions"
* tag 'riscv-for-linus-6.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: Add SBI debug trigger extension and function ids
riscv/atomic.h: use RISCV_FULL_BARRIER in _arch_atomic* function.
riscv: hwprobe: export Zilsd and Zclsd ISA extensions
riscv: add ISA extension parsing for Zilsd and Zclsd
dt-bindings: riscv: add Zilsd and Zclsd extension descriptions
riscv: mm: use xchg() on non-atomic_long_t variables, not atomic_long_xchg()
riscv: mm: ptep_get_and_clear(): avoid atomic ops when !CONFIG_SMP
riscv: mm: pmdp_huge_get_and_clear(): avoid atomic ops when !CONFIG_SMP
riscv: signal: abstract header saving for setup_sigcontext
It looks like the buffer allocated and mapped in add_card() is done
with size RCV_BUFFER_SIZE which is 16 KB and 4KB.
Fixes: 286468210d83 ("firewire: new driver: nosy - IEEE 1394 traffic sniffer")
Co-developed-by: Thomas Fourier <fourier.thomas@gmail.com>
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Co-developed-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20251216165420.38355-2-fourier.thomas@gmail.com
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
The driver updates struct sci_port::tx_cookie to zero right before the TX
work is scheduled, or to -EINVAL when DMA is disabled.
dma_async_is_complete(), called through dma_cookie_status() (and possibly
through dmaengine_tx_status()), considers cookies valid only if they have
values greater than or equal to 1.
Passing zero or -EINVAL to dmaengine_tx_status() before any TX DMA
transfer has started leads to an incorrect TX status being reported, as the
cookie is invalid for the DMA subsystem. This may cause long wait times
when the serial device is opened for configuration before any TX activity
has occurred.
Check that the TX cookie is valid before passing it to
dmaengine_tx_status().
Fixes: 7cc0e0a43a91 ("serial: sh-sci: Check if TX data was written to device in .tx_empty()")
Cc: stable <stable@kernel.org>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/20251217135759.402015-1-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>