Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
code
Clone this repository
https://tangled.org/tjh.dev/kernel
git@gordian.tjh.dev:tjh.dev/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Pull Kbuild fixes from Masahiro Yamada:
- Use the specified $(LD) when building userprogs with Clang
- Pass the correct target triple when compile-testing UAPI headers
with Clang
- Fix pacman-pkg build error with KBUILD_OUTPUT
* tag 'kbuild-fixes-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: install-extmod-build: Fix build when specifying KBUILD_OUTPUT
docs: Kconfig: fix defconfig description
kbuild: hdrcheck: fix cross build with clang
kbuild: userprogs: use correct lld when linking through clang
Pull USB fixes from Greg KH:
"Here are some small USB driver fixes for some reported issues. These
contain:
- typec driver fixes
- dwc3 driver fixes
- xhci driver fixes
- renesas controller fixes
- gadget driver fixes
- a new USB quirk added
All of these have been in linux-next with no reported issues"
* tag 'usb-6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
usb: typec: ucsi: Fix NULL pointer access
usb: quirks: Add DELAY_INIT and NO_LPM for Prolific Mass Storage Card Reader
usb: xhci: Fix host controllers "dying" after suspend and resume
usb: dwc3: Set SUSPENDENABLE soon after phy init
usb: hub: lack of clearing xHC resources
usb: renesas_usbhs: Flush the notify_hotplug_work
usb: renesas_usbhs: Use devm_usb_get_phy()
usb: renesas_usbhs: Call clk_put()
usb: dwc3: gadget: Prevent irq storm when TH re-executes
usb: gadget: Check bmAttributes only if configuration is valid
xhci: Restrict USB4 tunnel detection for USB3 devices to Intel hosts
usb: xhci: Enable the TRB overfetch quirk on VIA VL805
usb: gadget: Fix setting self-powered state on suspend
usb: typec: ucsi: increase timeout for PPM reset operations
acpi: typec: ucsi: Introduce a ->poll_cci method
usb: typec: tcpci_rt1711h: Unmask alert interrupts to fix functionality
usb: gadget: Set self-powered based on MaxPower and bmAttributes
usb: gadget: u_ether: Set is_suspend flag if remote wakeup fails
usb: atm: cxacru: fix a flaw in existing endpoint checks
Since commit 5f73e7d0386d ("kbuild: refactor cross-compiling
linux-headers package"), the linux-headers pacman package fails
to build when "O=" is set. The build system complains:
/mnt/chroot/linux/scripts/Makefile.build:41: mnt/chroots/linux-mainline/pacman/linux-upstream/pkg/linux-upstream-headers/usr//lib/modules/6.14.0-rc3-00350-g771dba31fffc/build/scripts/Makefile: No such file or directory
This is because the "srcroot" variable is set to "." and the
"build" variable is set to the absolute path. This makes the
"src" variables point to wrong directory.
Change the "build" variable to a relative path to "." to
fix build.
Fixes: 5f73e7d0386d ("kbuild: refactor cross-compiling linux-headers package")
Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull driver core fix from Greg KH:
"Here is a single driver core fix that resolves a reported memory leak.
It's been in linux-next for 2 weeks now with no reported problems"
* tag 'driver-core-6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
drivers: core: fix device leak in __fw_devlink_relax_cycles()
Resources should be released only after all threads that utilize them
have been destroyed.
This commit ensures that resources are not released prematurely by waiting
for the associated workqueue to complete before deallocating them.
Cc: stable <stable@kernel.org>
Fixes: b9aa02ca39a4 ("usb: typec: ucsi: Add polling mechanism for partner tasks like alt mode checking")
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20250305111739.1489003-2-akuchynski@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 2a86f6612164 ("kbuild: use KBUILD_DEFCONFIG as the fallback
for DEFCONFIG_LIST") removed arch/$ARCH/defconfig; however,
the document has not been updated to reflect this change yet.
Signed-off-by: Satoru Takeuchi <satoru.takeuchi@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull char/misc/IIO driver fixes from Greg KH:
"Here are a number of misc and char and iio driver fixes that have been
sitting in my tree for way too long. They contain:
- iio driver fixes for reported issues
- regression fix for rtsx_usb card reader
- mei and mhi driver fixes
- small virt driver fixes
- ntsync permissions fix
- other tiny driver fixes for reported problems.
All of these have been in linux-next for quite a while with no
reported issues"
* tag 'char-misc-6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (30 commits)
Revert "drivers/card_reader/rtsx_usb: Restore interrupt based detection"
ntsync: Check wait count based on byte size.
bus: simple-pm-bus: fix forced runtime PM use
char: misc: deallocate static minor in error path
eeprom: digsy_mtc: Make GPIO lookup table match the device
drivers: virt: acrn: hsm: Use kzalloc to avoid info leak in pmcmd_ioctl
binderfs: fix use-after-free in binder_devices
slimbus: messaging: Free transaction ID in delayed interrupt scenario
vbox: add HAS_IOPORT dependency
cdx: Fix possible UAF error in driver_override_show()
intel_th: pci: Add Panther Lake-P/U support
intel_th: pci: Add Panther Lake-H support
intel_th: pci: Add Arrow Lake support
intel_th: msu: Fix less trivial kernel-doc warnings
intel_th: msu: Fix kernel-doc warnings
MAINTAINERS: change maintainer for FSI
ntsync: Set the permissions to be 0666
bus: mhi: host: pci_generic: Use pci_try_reset_function() to avoid deadlock
mei: vsc: Use "wakeuphostint" when getting the host wakeup GPIO
mei: me: add panther lake P DID
...
Commit bac3b10b78e5 ("driver core: fw_devlink: Stop trying to optimize
cycle detection logic") introduced a new struct device *con_dev and a
get_dev_from_fwnode() call to get it, but without adding a corresponding
put_device().
Closes: https://lore.kernel.org/all/20241204124826.2e055091@booty/
Fixes: bac3b10b78e5 ("driver core: fw_devlink: Stop trying to optimize cycle detection logic")
Cc: stable@vger.kernel.org
Reviewed-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://lore.kernel.org/r/20250213-fix__fw_devlink_relax_cycles_missing_device_put-v2-1-8cd3b03e6a3f@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When used on Huawei hisi platforms, Prolific Mass Storage Card Reader
which the VID:PID is in 067b:2731 might fail to enumerate at boot time
and doesn't work well with LPM enabled, combination quirks:
USB_QUIRK_DELAY_INIT + USB_QUIRK_NO_LPM
fixed the problems.
Signed-off-by: Miao Li <limiao@kylinos.cn>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20250304070757.139473-1-limiao870622@163.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The headercheck tries to call clang with a mix of compiler arguments
that don't include the target architecture. When building e.g. x86
headers on arm64, this produces a warning like
clang: warning: unknown platform, assuming -mfloat-abi=soft
Add in the KBUILD_CPPFLAGS, which contain the target, in order to make it
build properly.
See also 1b71c2fb04e7 ("kbuild: userprogs: fix bitsize and target
detection on clang").
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Fixes: feb843a469fb ("kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Pull KVM fixes from Paolo Bonzini:
"arm64:
- Fix a couple of bugs affecting pKVM's PSCI relay implementation
when running in the hVHE mode, resulting in the host being entered
with the MMU in an unknown state, and EL2 being in the wrong mode
x86:
- Set RFLAGS.IF in C code on SVM to get VMRUN out of the STI shadow
- Ensure DEBUGCTL is context switched on AMD to avoid running the
guest with the host's value, which can lead to unexpected bus lock
#DBs
- Suppress DEBUGCTL.BTF on AMD (to match Intel), as KVM doesn't
properly emulate BTF. KVM's lack of context switching has meant BTF
has always been broken to some extent
- Always save DR masks for SNP vCPUs if DebugSwap is *supported*, as
the guest can enable DebugSwap without KVM's knowledge
- Fix a bug in mmu_stress_tests where a vCPU could finish the "writes
to RO memory" phase without actually generating a write-protection
fault
- Fix a printf() goof in the SEV smoke test that causes build
failures with -Werror
- Explicitly zero EAX and EBX in CPUID.0x8000_0022 output when
PERFMON_V2 isn't supported by KVM"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: x86: Explicitly zero EAX and EBX when PERFMON_V2 isn't supported by KVM
KVM: selftests: Fix printf() format goof in SEV smoke test
KVM: selftests: Ensure all vCPUs hit -EFAULT during initial RO stage
KVM: SVM: Don't rely on DebugSwap to restore host DR0..DR3
KVM: SVM: Save host DR masks on CPUs with DebugSwap
KVM: arm64: Initialize SCTLR_EL1 in __kvm_hyp_init_cpu()
KVM: arm64: Initialize HCR_EL2.E2H early
KVM: x86: Snapshot the host's DEBUGCTL after disabling IRQs
KVM: SVM: Manually context switch DEBUGCTL if LBR virtualization is disabled
KVM: x86: Snapshot the host's DEBUGCTL in common x86
KVM: SVM: Suppress DEBUGCTL.BTF on AMD
KVM: SVM: Drop DEBUGCTL[5:2] from guest's effective value
KVM: selftests: Assert that STI blocking isn't set after event injection
KVM: SVM: Set RFLAGS.IF=1 in C code, to get VMRUN out of the STI shadow
This reverts commit 235b630eda072d7e7b102ab346d6b8a2c028a772.
This commit was found responsible for issues with SD card recognition,
as users had to re-insert their cards in the readers and wait for a
while. As for some people the SD card was involved in the boot process
it also caused boot failures.
Cc: stable@vger.kernel.org
Link: https://bbs.archlinux.org/viewtopic.php?id=303321
Fixes: 235b630eda07 ("drivers/card_reader/rtsx_usb: Restore interrupt based detection")
Reported-by: qf <quintafeira@tutanota.com>
Closes: https://lore.kernel.org/all/1de87dfa-1e81-45b7-8dcb-ad86c21d5352@heusel.eu
Signed-off-by: Christian Heusel <christian@heusel.eu>
Link: https://lore.kernel.org/r/20250224-revert-sdcard-patch-v1-1-d1a457fbb796@heusel.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A recent cleanup went a bit too far and dropped clearing the cycle bit
of link TRBs, so it stays different from the rest of the ring half of
the time. Then a race occurs: if the xHC reaches such link TRB before
more commands are queued, the link's cycle bit unintentionally matches
the xHC's cycle so it follows the link and waits for further commands.
If more commands are queued before the xHC gets there, inc_enq() flips
the bit so the xHC later sees a mismatch and stops executing commands.
This function is called before suspend and 50% of times after resuming
the xHC is doomed to get stuck sooner or later. Then some Stop Endpoint
command fails to complete in 5 seconds and this shows up
xhci_hcd 0000:00:10.0: xHCI host not responding to stop endpoint command
xhci_hcd 0000:00:10.0: xHCI host controller not responding, assume dead
xhci_hcd 0000:00:10.0: HC died; cleaning up
followed by loss of all USB decives on the affected bus. That's if you
are lucky, because if Set Deq gets stuck instead, the failure is silent.
Likely responsible for kernel bug 219824. I found this while searching
for possible causes of that regression and reproduced it locally before
hearing back from the reporter. To repro, simply wait for link cycle to
become set (debugfs), then suspend, resume and wait. To accelerate the
failure I used a script which repeatedly starts and stops a UVC camera.
Some HCs get fully reinitialized on resume and they are not affected.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219824
Fixes: 36b972d4b7ce ("usb: xhci: improve xhci_clear_command_ring()")
Cc: stable@vger.kernel.org
Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250304113147.3322584-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The userprog infrastructure links objects files through $(CC).
Either explicitly by manually calling $(CC) on multiple object files or
implicitly by directly compiling a source file to an executable.
The documentation at Documentation/kbuild/llvm.rst indicates that ld.lld
would be used for linking if LLVM=1 is specified.
However clang instead will use either a globally installed cross linker
from $PATH called ${target}-ld or fall back to the system linker, which
probably does not support crosslinking.
For the normal kernel build this is not an issue because the linker is
always executed directly, without the compiler being involved.
Explicitly pass --ld-path to clang so $(LD) is respected.
As clang 13.0.1 is required to build the kernel, this option is available.
Fixes: 7f3a59db274c ("kbuild: add infrastructure to build userspace programs")
Cc: stable@vger.kernel.org # needs wrapping in $(cc-option) for < 6.9
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull misc fixes from Andrew Morton:
"33 hotfixes. 24 are cc:stable and the remainder address post-6.13
issues or aren't considered necessary for -stable kernels.
26 are for MM and 7 are for non-MM.
- "mm: memory_failure: unmap poisoned folio during migrate properly"
from Ma Wupeng fixes a couple of two year old bugs involving the
migration of hwpoisoned folios.
- "selftests/damon: three fixes for false results" from SeongJae Park
fixes three one year old bugs in the SAMON selftest code.
The remainder are singletons and doubletons. Please see the individual
changelogs for details"
* tag 'mm-hotfixes-stable-2025-03-08-16-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (33 commits)
mm/page_alloc: fix uninitialized variable
rapidio: add check for rio_add_net() in rio_scan_alloc_net()
rapidio: fix an API misues when rio_add_net() fails
MAINTAINERS: .mailmap: update Sumit Garg's email address
Revert "mm/page_alloc.c: don't show protection in zone's ->lowmem_reserve[] for empty zone"
mm: fix finish_fault() handling for large folios
mm: don't skip arch_sync_kernel_mappings() in error paths
mm: shmem: remove unnecessary warning in shmem_writepage()
userfaultfd: fix PTE unmapping stack-allocated PTE copies
userfaultfd: do not block on locking a large folio with raised refcount
mm: zswap: use ATOMIC_LONG_INIT to initialize zswap_stored_pages
mm: shmem: fix potential data corruption during shmem swapin
mm: fix kernel BUG when userfaultfd_move encounters swapcache
selftests/damon/damon_nr_regions: sort collected regiosn before checking with min/max boundaries
selftests/damon/damon_nr_regions: set ops update for merge results check to 100ms
selftests/damon/damos_quota: make real expectation of quota exceeds
include/linux/log2.h: mark is_power_of_2() with __always_inline
NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback
mm, swap: avoid BUG_ON in relocate_cluster()
mm: swap: use correct step in loop to wait all clusters in wait_for_allocation()
...