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.
Clone this repository
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
Pull xfs fix from Carlos Maiolino:
"A single out-of-bounds fix, nothing special"
* tag 'xfs-fixes-6.18-rc7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: fix out of bounds memory read error in symlink repair
Pull SCSI fixes from James Bottomley:
"One target driver fix and one scsi-generic one. The latter is 10 lines
because the problem lock has to be dropped and re-taken around the
call causing the sleep in atomic"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: sg: Do not sleep in atomic context
scsi: target: tcm_loop: Fix segfault in tcm_loop_tpg_address_show()
xfs/286 produced this report on my test fleet:
==================================================================
BUG: KFENCE: out-of-bounds read in memcpy_orig+0x54/0x110
Out-of-bounds read at 0xffff88843fe9e038 (184B right of kfence-#184):
memcpy_orig+0x54/0x110
xrep_symlink_salvage_inline+0xb3/0xf0 [xfs]
xrep_symlink_salvage+0x100/0x110 [xfs]
xrep_symlink+0x2e/0x80 [xfs]
xrep_attempt+0x61/0x1f0 [xfs]
xfs_scrub_metadata+0x34f/0x5c0 [xfs]
xfs_ioc_scrubv_metadata+0x387/0x560 [xfs]
xfs_file_ioctl+0xe23/0x10e0 [xfs]
__x64_sys_ioctl+0x76/0xc0
do_syscall_64+0x4e/0x1e0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
kfence-#184: 0xffff88843fe9df80-0xffff88843fe9dfea, size=107, cache=kmalloc-128
allocated by task 3470 on cpu 1 at 263329.131592s (192823.508886s ago):
xfs_init_local_fork+0x79/0xe0 [xfs]
xfs_iformat_local+0xa4/0x170 [xfs]
xfs_iformat_data_fork+0x148/0x180 [xfs]
xfs_inode_from_disk+0x2cd/0x480 [xfs]
xfs_iget+0x450/0xd60 [xfs]
xfs_bulkstat_one_int+0x6b/0x510 [xfs]
xfs_bulkstat_iwalk+0x1e/0x30 [xfs]
xfs_iwalk_ag_recs+0xdf/0x150 [xfs]
xfs_iwalk_run_callbacks+0xb9/0x190 [xfs]
xfs_iwalk_ag+0x1dc/0x2f0 [xfs]
xfs_iwalk_args.constprop.0+0x6a/0x120 [xfs]
xfs_iwalk+0xa4/0xd0 [xfs]
xfs_bulkstat+0xfa/0x170 [xfs]
xfs_ioc_fsbulkstat.isra.0+0x13a/0x230 [xfs]
xfs_file_ioctl+0xbf2/0x10e0 [xfs]
__x64_sys_ioctl+0x76/0xc0
do_syscall_64+0x4e/0x1e0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
CPU: 1 UID: 0 PID: 1300113 Comm: xfs_scrub Not tainted 6.18.0-rc4-djwx #rc4 PREEMPT(lazy) 3d744dd94e92690f00a04398d2bd8631dcef1954
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-4.module+el8.8.0+21164+ed375313 04/01/2014
==================================================================
On further analysis, I realized that the second parameter to min() is
not correct. xfs_ifork::if_bytes is the size of the xfs_ifork::if_data
buffer. if_bytes can be smaller than the data fork size because:
(a) the forkoff code tries to keep the data area as large as possible
(b) for symbolic links, if_bytes is the ondisk file size + 1
(c) forkoff is always a multiple of 8.
Case in point: for a single-byte symlink target, forkoff will be
8 but the buffer will only be 2 bytes long.
In other words, the logic here is wrong and we walk off the end of the
incore buffer. Fix that.
Cc: stable@vger.kernel.org # v6.10
Fixes: 2651923d8d8db0 ("xfs: online repair of symbolic links")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Pull input fixes from Dmitry Torokhov:
- INPUT_PROP_HAPTIC_TOUCHPAD definition added early in 6.18 cycle has
been renamed to INPUT_PROP_PRESSUREPAD to better reflect the kind of
devices it is supposed to be set for
- a new ID for a touchscreen found in Ayaneo Flip DS in Goodix driver
- Goodix driver no longer tries to set reset pin as "input" as it
causes issues when there is no pull up resistor installed on the
board
- fixes for cros_ec_keyb, imx_sc_key, and pegasus-notetaker drivers to
deal with potential out-of-bounds access and memory corruption issues
* tag 'input-for-v6.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: rename INPUT_PROP_HAPTIC_TOUCHPAD to INPUT_PROP_PRESSUREPAD
Input: cros_ec_keyb - fix an invalid memory access
Input: imx_sc_key - fix memory corruption on unload
Input: pegasus-notetaker - fix potential out-of-bounds access
Input: goodix - remove setting of RST pin to input
Input: goodix - add support for ACPI ID GDIX1003
sg_finish_rem_req() calls blk_rq_unmap_user(). The latter function may
sleep. Hence, call sg_finish_rem_req() with interrupts enabled instead
of disabled.
Reported-by: syzbot+c01f8e6e73f20459912e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-scsi/691560c4.a70a0220.3124cb.001a.GAE@google.com/
Cc: Hannes Reinecke <hare@suse.de>
Cc: stable@vger.kernel.org
Fixes: 97d27b0dd015 ("scsi: sg: close race condition in sg_remove_sfp_usercontext()")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251113181643.1108973-1-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
kmemleak occasionally reports leaking xfs_busy_extents structure
from xfs_scrub calls after running xfs/528 (but attributed to following
tests), which seems to be caused by not freeing the xfs_busy_extents
structure when tr.queued is 0 and xfs_trim_rtgroup_extents breaks out
of the main loop. Free the structure in this case.
Fixes: a3315d11305f ("xfs: use rtgroup busy extent list for FITRIM")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Pull RISC-V fixes from Paul Walmsley:
- Correct the MIPS RISC-V/JEDEC vendor ID
- Fix the system shutdown behavior in the legacy case where
CONFIG_RISCV_SBI_V01 is set, but the firmware implementation
doesn't support the older v0.1 system shutdown method
- Align some tools/ macro definitions with the corresponding
kernel headers
* tag 'riscv-for-linus-6.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
tools: riscv: Fixed misalignment of CSR related definitions
riscv: sbi: Prefer SRST shutdown over legacy
riscv: Update MIPS vendor id to 0x127
And expand it to encompass all pressure pads.
Definition: "pressure pad" as used here as includes all touchpads that
use physical pressure to convert to click, without physical hinges. Also
called haptic touchpads in general parlance, Synaptics calls them
ForcePads.
Most (all?) pressure pads are currently advertised as
INPUT_PROP_BUTTONPAD. The suggestion to identify them as pressure pads
by defining the resolution on ABS_MT_PRESSURE has been in the docs since
commit 20ccc8dd38a3 ("Documentation: input: define
ABS_PRESSURE/ABS_MT_PRESSURE resolution as grams") but few devices
provide this information.
In userspace it's thus impossible to determine whether a device is a
true pressure pad (pressure equals pressure) or a normal clickpad with
(pressure equals finger size).
Commit 7075ae4ac9db ("Input: add INPUT_PROP_HAPTIC_TOUCHPAD") introduces
INPUT_PROP_HAPTIC_TOUCHPAD but restricted it to those touchpads that
have support for userspace-controlled effects. Let's expand and rename
that definition to include all pressure pad touchpads since those that
do support FF effects can be identified by the presence of the
FF_HAPTIC bit.
This means:
- clickpad: INPUT_PROP_BUTTONPAD
- pressurepad: INPUT_PROP_BUTTONPAD + INPUT_PROP_PRESSUREPAD
- pressurepad with configurable haptics:
INPUT_PROP_BUTTONPAD + INPUT_PROP_PRESSUREPAD + FF_HAPTIC
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://patch.msgid.link/20251106114534.GA405512@tassie
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
If the allocation of tl_hba->sh fails in tcm_loop_driver_probe() and we
attempt to dereference it in tcm_loop_tpg_address_show() we will get a
segfault, see below for an example. So, check tl_hba->sh before
dereferencing it.
Unable to allocate struct scsi_host
BUG: kernel NULL pointer dereference, address: 0000000000000194
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 8356 Comm: tokio-runtime-w Not tainted 6.6.104.2-4.azl3 #1
Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 09/28/2024
RIP: 0010:tcm_loop_tpg_address_show+0x2e/0x50 [tcm_loop]
...
Call Trace:
<TASK>
configfs_read_iter+0x12d/0x1d0 [configfs]
vfs_read+0x1b5/0x300
ksys_read+0x6f/0xf0
...
Cc: stable@vger.kernel.org
Fixes: 2628b352c3d4 ("tcm_loop: Show address of tpg in configfs")
Signed-off-by: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Allen Pais <apais@linux.microsoft.com>
Link: https://patch.msgid.link/1762370746-6304-1-git-send-email-hamzamahfooz@linux.microsoft.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
xfs_select_open_zone_mru needs to pass XFS_ZONE_ALLOC_OK to
xfs_try_use_zone because we only want to tightly pack into zones of the
same or a compatible temperature instead of any available zone.
This got broken in commit 0301dae732a5 ("xfs: refactor hint based zone
allocation"), which failed to update this particular caller when
switching to an enum. xfs/638 sometimes, but not reliably fails due to
this change.
Fixes: 0301dae732a5 ("xfs: refactor hint based zone allocation")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Pull selinux fixes from Paul Moore:
"Three SELinux patches for v6.18 to fix issues around accessing the
per-task decision cache that we introduced in v6.16 to help reduce
SELinux overhead on path walks. The problem was that despite the cache
being located in the SELinux "task_security_struct", the parent struct
wasn't actually tied to the task, it was tied to a cred.
Historically SELinux did locate the task_security_struct in the
task_struct's security blob, but it was later relocated to the cred
struct when the cred work happened, as it made the most sense at the
time.
Unfortunately we never did the task_security_struct to
cred_security_struct rename work (avoid code churn maybe? who knows)
because it didn't really matter at the time. However, it suddenly
became a problem when we added a per-task cache to a per-cred object
and didn't notice because of the old, no-longer-correct struct naming.
Thanks to KCSAN for flagging this, as the silly humans running things
forgot that the task_security_struct was a big lie.
This contains three patches, only one of which actually fixes the
problem described above and moves the SELinux decision cache from the
per-cred struct to a newly (re)created per-task struct.
The other two patches, which form the bulk of the diffstat, take care
of the associated renaming tasks so we can hopefully avoid making the
same stupid mistake in the future.
For the record, I did contemplate sending just a fix for the cache,
leaving the renaming patches for the upcoming merge window, but the
type/variable naming ended up being pretty awful and would have made
v6.18 an outlier stuck between the "old" names and the "new" names in
v6.19. The renaming patches are also fairly mechanical/trivial and
shouldn't pose much risk despite their size.
TLDR; naming things may be hard, but if you mess it up bad things
happen"
* tag 'selinux-pr-20251121' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: rename the cred_security_struct variables to "crsec"
selinux: move avdcache to per-task security struct
selinux: rename task_security_struct to cred_security_struct
The file tools/arch/riscv/include/asm/csr.h borrows from
arch/riscv/include/asm/csr.h, and subsequent modifications
related to CSR should maintain consistency.
Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
Link: https://patch.msgid.link/20251114071215.816-1-cp0613@linux.alibaba.com
[pjw@kernel.org: dropped Fixes: lines for patches that weren't broken; removed superfluous blank line]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Sync up with the mainline to bring in definition of
INPUT_PROP_HAPTIC_TOUCHPAD.
After DME Link Startup, the error return value is set to the MIPI UniPro
GenericErrorCode which can be 0 (SUCCESS) or 1 (FAILURE). Upon failure
during driver probe, the error code 1 is propagated back to the driver
probe function which must return a negative value to indicate an error,
but 1 is not negative, so the probe is considered to be successful even
though it failed. Subsequently, removing the driver results in an oops
because it is not in a valid state.
This happens because none of the callers of ufshcd_init() expect a
non-negative error code.
Fix the return value and documentation to match actual usage.
Fixes: 69f5eb78d4b0 ("scsi: ufs: core: Move the ufshcd_device_init(hba, true) call")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251024085918.31825-5-adrian.hunter@intel.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Drop the rtgrop reference when xfs_init_zone fails for a conventional
device.
Fixes: 4e4d52075577 ("xfs: add the zoned space allocator")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Pull LoongArch fixes from Huacai Chen:
"Use UAPI types in ptrace UAPI header to fix nolibc ptrace.
Fix CPU name display, NUMA node parsing, kexec/kdump, PCI init and BPF
trampoline"
* tag 'loongarch-fixes-6.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
LoongArch: BPF: Disable trampoline for kernel module function trace
LoongArch: Don't panic if no valid cache info for PCI
LoongArch: Mask all interrupts during kexec/kdump
LoongArch: Fix NUMA node parsing with numa_memblks
LoongArch: Consolidate CPU names in /proc/cpuinfo
LoongArch: Use UAPI types in ptrace UAPI header