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
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Pull Kbuild fixes from Masahiro Yamada:
- Move warnings about linux/export.h from W=1 to W=2
- Fix structure type overrides in gendwarfksyms
* tag 'kbuild-fixes-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
gendwarfksyms: Fix structure type overrides
kbuild: move warnings about linux/export.h from W=1 to W=2
Pull smb client fixes from Steve French:
- SMB3.1.1 POSIX extensions fix for char remapping
- Fix for repeated directory listings when directory leases enabled
- deferred close handle reuse fix
* tag 'v6.16-rc1-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb: improve directory cache reuse for readdir operations
smb: client: fix perf regression with deferred closes
smb: client: disable path remapping with POSIX extensions
As we always iterate through the entire die_map when expanding
type strings, recursively processing referenced types in
type_expand_child() is not actually necessary. Furthermore,
the type_string kABI rule added in commit c9083467f7b9
("gendwarfksyms: Add a kABI rule to override type strings") can
fail to override type strings for structures due to a missing
kabi_get_type_string() check in this function.
Fix the issue by dropping the unnecessary recursion and moving
the override check to type_expand(). Note that symbol versions
are otherwise unchanged with this patch.
Fixes: c9083467f7b9 ("gendwarfksyms: Add a kABI rule to override type strings")
Reported-by: Giuliano Procida <gprocida@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull iommu fix from Joerg Roedel:
- Fix PTE size calculation for NVidia Tegra
* tag 'iommu-fixes-v6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux:
iommu/tegra: Fix incorrect size calculation
Currently, cached directory contents were not reused across subsequent
'ls' operations because the cache validity check relied on comparing
the ctx pointer, which changes with each readdir invocation. As a
result, the cached dir entries was not marked as valid and the cache was
not utilized for subsequent 'ls' operations.
This change uses the file pointer, which remains consistent across all
readdir calls for a given directory instance, to associate and validate
the cache. As a result, cached directory contents can now be
correctly reused, improving performance for repeated directory listings.
Performance gains with local windows SMB server:
Without the patch and default actimeo=1:
1000 directory enumeration operations on dir with 10k files took 135.0s
With this patch and actimeo=0:
1000 directory enumeration operations on dir with 10k files took just 5.1s
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
This hides excessive warnings, as nobody builds with W=2.
Fixes: a934a57a42f6 ("scripts/misc-check: check missing #include <linux/export.h> when W=1")
Fixes: 7d95680d64ac ("scripts/misc-check: check unnecessary #include <linux/export.h> when W=1")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Pull block fixes from Jens Axboe:
- Fix for a deadlock on queue freeze with zoned writes
- Fix for zoned append emulation
- Two bio folio fixes, for sparsemem and for very large folios
- Fix for a performance regression introduced in 6.13 when plug
insertion was changed
- Fix for NVMe passthrough handling for polled IO
- Document the ublk auto registration feature
- loop lockdep warning fix
* tag 'block-6.16-20250614' of git://git.kernel.dk/linux:
nvme: always punt polled uring_cmd end_io work to task_work
Documentation: ublk: Separate UBLK_F_AUTO_BUF_REG fallback behavior sublists
block: Fix bvec_set_folio() for very large folios
bio: Fix bio_first_folio() for SPARSEMEM without VMEMMAP
block: use plug request list tail for one-shot backmerge attempt
block: don't use submit_bio_noacct_nocheck in blk_zone_wplug_bio_work
block: Clear BIO_EMULATES_ZONE_APPEND flag on BIO completion
ublk: document auto buffer registration(UBLK_F_AUTO_BUF_REG)
loop: move lo_set_size() out of queue freeze
This driver uses a mixture of ways to get the size of a PTE,
tegra_smmu_set_pde() did it as sizeof(*pd) which became wrong when pd
switched to a struct tegra_pd.
Switch pd back to a u32* in tegra_smmu_set_pde() so the sizeof(*pd)
returns 4.
Fixes: 50568f87d1e2 ("iommu/terga: Do not use struct page as the handle for as->pd memory")
Reported-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
Closes: https://lore.kernel.org/all/62e7f7fe-6200-4e4f-ad42-d58ad272baa6@tecnico.ulisboa.pt/
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Tested-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
Link: https://lore.kernel.org/r/0-v1-da7b8b3d57eb+ce-iommu_terga_sizeof_jgg@nvidia.com
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Customer reported that one of their applications started failing to
open files with STATUS_INSUFFICIENT_RESOURCES due to NetApp server
hitting the maximum number of opens to same file that it would allow
for a single client connection.
It turned out the client was failing to reuse open handles with
deferred closes because matching ->f_flags directly without masking
off O_CREAT|O_EXCL|O_TRUNC bits first broke the comparision and then
client ended up with thousands of deferred closes to same file. Those
bits are already satisfied on the original open, so no need to check
them against existing open handles.
Reproducer:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <pthread.h>
#define NR_THREADS 4
#define NR_ITERATIONS 2500
#define TEST_FILE "/mnt/1/test/dir/foo"
static char buf[64];
static void *worker(void *arg)
{
int i, j;
int fd;
for (i = 0; i < NR_ITERATIONS; i++) {
fd = open(TEST_FILE, O_WRONLY|O_CREAT|O_APPEND, 0666);
for (j = 0; j < 16; j++)
write(fd, buf, sizeof(buf));
close(fd);
}
}
int main(int argc, char *argv[])
{
pthread_t t[NR_THREADS];
int fd;
int i;
fd = open(TEST_FILE, O_WRONLY|O_CREAT|O_TRUNC, 0666);
close(fd);
memset(buf, 'a', sizeof(buf));
for (i = 0; i < NR_THREADS; i++)
pthread_create(&t[i], NULL, worker, NULL);
for (i = 0; i < NR_THREADS; i++)
pthread_join(t[i], NULL);
return 0;
}
Before patch:
$ mount.cifs //srv/share /mnt/1 -o ...
$ mkdir -p /mnt/1/test/dir
$ gcc repro.c && ./a.out
...
number of opens: 1391
After patch:
$ mount.cifs //srv/share /mnt/1 -o ...
$ mkdir -p /mnt/1/test/dir
$ gcc repro.c && ./a.out
...
number of opens: 1
Cc: linux-cifs@vger.kernel.org
Cc: David Howells <dhowells@redhat.com>
Cc: Jay Shin <jaeshin@redhat.com>
Cc: Pierguido Lambri <plambri@redhat.com>
Fixes: b8ea3b1ff544 ("smb: enable reuse of deferred file handles for write operations")
Acked-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull io_uring fixes from Jens Axboe:
- Fix for a race between SQPOLL exit and fdinfo reading.
It's slim and I was only able to reproduce this with an artificial
delay in the kernel. Followup sparse fix as well to unify the access
to ->thread.
- Fix for multiple buffer peeking, avoiding truncation if possible.
- Run local task_work for IOPOLL reaping when the ring is exiting.
This currently isn't done due to an assumption that polled IO will
never need task_work, but a fix on the block side is going to change
that.
* tag 'io_uring-6.16-20250614' of git://git.kernel.dk/linux:
io_uring: run local task_work from ring exit IOPOLL reaping
io_uring/kbuf: don't truncate end buffer for multiple buffer peeks
io_uring: consistently use rcu semantics with sqpoll thread
io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()
Currently NVMe uring_cmd completions will complete locally, if they are
polled. This is done because those completions are always invoked from
task context. And while that is true, there's no guarantee that it's
invoked under the right ring context, or even task. If someone does
NVMe passthrough via multiple threads and with a limited number of
poll queues, then ringA may find completions from ringB. For that case,
completing the request may not be sound.
Always just punt the passthrough completions via task_work, which will
redirect the completion, if needed.
Cc: stable@vger.kernel.org
Fixes: 585079b6e425 ("nvme: wire up async polling for io passthrough commands")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If SMB 3.1.1 POSIX Extensions are available and negotiated, the client
should be able to use all characters and not remap anything. Currently, the
user has to explicitly request this behavior by specifying the "nomapposix"
mount option.
Link: https://lore.kernel.org/4195bb677b33d680e77549890a4f4dd3b474ceaf.camel@rx2.rx-server.de
Signed-off-by: Philipp Kerling <pkerling@casix.org>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull turbostat updates from Len Brown:
- Add initial DMR support, which required smarter RAPL probe
- Fix AMD MSR RAPL energy reporting
- Add RAPL power limit configuration output
- Minor fixes
* tag 'turbostat-2025.06.08' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
tools/power turbostat: version 2025.06.08
tools/power turbostat: Add initial support for BartlettLake
tools/power turbostat: Add initial support for DMR
tools/power turbostat: Dump RAPL sysfs info
tools/power turbostat: Avoid probing the same perf counters
tools/power turbostat: Allow probing RAPL with platform_features->rapl_msrs cleared
tools/power turbostat: Clean up add perf/msr counter logic
tools/power turbostat: Introduce add_msr_counter()
tools/power turbostat: Remove add_msr_perf_counter_()
tools/power turbostat: Remove add_cstate_perf_counter_()
tools/power turbostat: Remove add_rapl_perf_counter_()
tools/power turbostat: Quit early for unsupported RAPL counters
tools/power turbostat: Always check rapl_joules flag
tools/power turbostat: Fix AMD package-energy reporting
tools/power turbostat: Fix RAPL_GFX_ALL typo
tools/power turbostat: Add Android support for MSR device handling
tools/power turbostat.8: pm_domain wording fix
tools/power turbostat.8: fix typo: idle_pct should be pct_idle
Pull Rust fix from Miguel Ojeda:
- 'hrtimer': fix future compile error when the 'impl_has_hr_timer!'
macro starts to get called
* tag 'rust-fixes-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: time: Fix compile error in impl_has_hr_timer macro
In preparation for needing to shift NVMe passthrough to always use
task_work for polled IO completions, ensure that those are suitably
run at exit time. See commit:
9ce6c9875f3e ("nvme: always punt polled uring_cmd end_io work to task_work")
for details on why that is necessary.
Signed-off-by: Jens Axboe <axboe@kernel.dk>