Commit Graph

422 Commits

Author SHA1 Message Date
Randy Dunlap
d5af79c05e Documentation: move dev-tools debugging files to process/debugging/
Move gdb and kgdb debugging documentation to the dedicated
debugging directory (Documentation/process/debugging/).
Adjust the index.rst files to follow the file movement.
Adjust files that refer to these moved files to follow the file movement.
Update location of kgdb.rst in MAINTAINERS file.
Add a link from dev-tools/index to process/debugging/index.

Note: translations are not updated.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Sebastian Fricke <sebastian.fricke@collabora.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: workflows@vger.kernel.org
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Daniel Thompson <danielt@kernel.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: linux-debuggers@vger.kernel.org
Cc: kgdb-bugreport@lists.sourceforge.net
Cc: Doug Anderson <dianders@chromium.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-serial@vger.kernel.org
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Daniel Thompson <danielt@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241210000041.305477-1-rdunlap@infradead.org
2024-12-17 13:46:53 -07:00
Cengiz Can
e551bd4109 Documentation: remove :kyb: tags
:kyb: is an extra markup that we should avoid when we can.

It worsens the plain-text reading experience and adds very little value
to rendered views.

Remove all :kbd: tags from Documentation/*

Signed-off-by: Cengiz Can <cengiz@kernel.wtf>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241202090514.1716-1-cengiz@kernel.wtf
2024-12-11 09:07:39 -07:00
Linus Torvalds
6a34dfa15d Merge tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Add generic support for built-in boot DTB files

 - Enable TAB cycling for dialog buttons in nconfig

 - Fix issues in streamline_config.pl

 - Refactor Kconfig

 - Add support for Clang's AutoFDO (Automatic Feedback-Directed
   Optimization)

 - Add support for Clang's Propeller, a profile-guided optimization.

 - Change the working directory to the external module directory for M=
   builds

 - Support building external modules in a separate output directory

 - Enable objtool for *.mod.o and additional kernel objects

 - Use lz4 instead of deprecated lz4c

 - Work around a performance issue with "git describe"

 - Refactor modpost

* tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (85 commits)
  kbuild: rename .tmp_vmlinux.kallsyms0.syms to .tmp_vmlinux0.syms
  gitignore: Don't ignore 'tags' directory
  kbuild: add dependency from vmlinux to resolve_btfids
  modpost: replace tdb_hash() with hash_str()
  kbuild: deb-pkg: add python3:native to build dependency
  genksyms: reduce indentation in export_symbol()
  modpost: improve error messages in device_id_check()
  modpost: rename alias symbol for MODULE_DEVICE_TABLE()
  modpost: rename variables in handle_moddevtable()
  modpost: move strstarts() to modpost.h
  modpost: convert do_usb_table() to a generic handler
  modpost: convert do_of_table() to a generic handler
  modpost: convert do_pnp_device_entry() to a generic handler
  modpost: convert do_pnp_card_entries() to a generic handler
  modpost: call module_alias_printf() from all do_*_entry() functions
  modpost: pass (struct module *) to do_*_entry() functions
  modpost: remove DEF_FIELD_ADDR_VAR() macro
  modpost: deduplicate MODULE_ALIAS() for all drivers
  modpost: introduce module_alias_printf() helper
  modpost: remove unnecessary check in do_acpi_entry()
  ...
2024-11-30 13:41:50 -08:00
Masahiro Yamada
13b25489b6 kbuild: change working directory to external module directory with M=
Currently, Kbuild always operates in the output directory of the kernel,
even when building external modules. This increases the risk of external
module Makefiles attempting to write to the kernel directory.

This commit switches the working directory to the external module
directory, allowing the removal of the $(KBUILD_EXTMOD)/ prefix from
some build artifacts.

The command for building external modules maintains backward
compatibility, but Makefiles that rely on working in the kernel
directory may break. In such cases, $(objtree) and $(srctree) should
be used to refer to the output and source directories of the kernel.

The appearance of the build log will change as follows:

[Before]

  $ make -C /path/to/my/linux M=/path/to/my/externel/module
  make: Entering directory '/path/to/my/linux'
    CC [M]  /path/to/my/externel/module/helloworld.o
    MODPOST /path/to/my/externel/module/Module.symvers
    CC [M]  /path/to/my/externel/module/helloworld.mod.o
    CC [M]  /path/to/my/externel/module/.module-common.o
    LD [M]  /path/to/my/externel/module/helloworld.ko
  make: Leaving directory '/path/to/my/linux'

[After]

  $ make -C /path/to/my/linux M=/path/to/my/externel/module
  make: Entering directory '/path/to/my/linux'
  make[1]: Entering directory '/path/to/my/externel/module'
    CC [M]  helloworld.o
    MODPOST Module.symvers
    CC [M]  helloworld.mod.o
    CC [M]  .module-common.o
    LD [M]  helloworld.ko
  make[1]: Leaving directory '/path/to/my/externel/module'
  make: Leaving directory '/path/to/my/linux'

Printing "Entering directory" twice is cumbersome. This will be
addressed later.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
2024-11-28 08:10:23 +09:00
Rong Xu
d5dc958361 kbuild: Add Propeller configuration for kernel build
Add the build support for using Clang's Propeller optimizer. Like
AutoFDO, Propeller uses hardware sampling to gather information
about the frequency of execution of different code paths within a
binary. This information is then used to guide the compiler's
optimization decisions, resulting in a more efficient binary.

The support requires a Clang compiler LLVM 19 or later, and the
create_llvm_prof tool
(https://github.com/google/autofdo/releases/tag/v0.30.1). This
commit is limited to x86 platforms that support PMU features
like LBR on Intel machines and AMD Zen3 BRS.

Here is an example workflow for building an AutoFDO+Propeller
optimized kernel:

1) Build the kernel on the host machine, with AutoFDO and Propeller
   build config
      CONFIG_AUTOFDO_CLANG=y
      CONFIG_PROPELLER_CLANG=y
   then
      $ make LLVM=1 CLANG_AUTOFDO_PROFILE=<autofdo_profile>

“<autofdo_profile>” is the profile collected when doing a non-Propeller
AutoFDO build. This step builds a kernel that has the same optimization
level as AutoFDO, plus a metadata section that records basic block
information. This kernel image runs as fast as an AutoFDO optimized
kernel.

2) Install the kernel on test/production machines.

3) Run the load tests. The '-c' option in perf specifies the sample
   event period. We suggest using a suitable prime number,
   like 500009, for this purpose.
   For Intel platforms:
      $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c <count> \
        -o <perf_file> -- <loadtest>
   For AMD platforms:
      The supported system are: Zen3 with BRS, or Zen4 with amd_lbr_v2
      # To see if Zen3 support LBR:
      $ cat proc/cpuinfo | grep " brs"
      # To see if Zen4 support LBR:
      $ cat proc/cpuinfo | grep amd_lbr_v2
      # If the result is yes, then collect the profile using:
      $ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a \
        -N -b -c <count> -o <perf_file> -- <loadtest>

4) (Optional) Download the raw perf file to the host machine.

5) Generate Propeller profile:
   $ create_llvm_prof --binary=<vmlinux> --profile=<perf_file> \
     --format=propeller --propeller_output_module_name \
     --out=<propeller_profile_prefix>_cc_profile.txt \
     --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt

   “create_llvm_prof” is the profile conversion tool, and a prebuilt
   binary for linux can be found on
   https://github.com/google/autofdo/releases/tag/v0.30.1 (can also build
   from source).

   "<propeller_profile_prefix>" can be something like
   "/home/user/dir/any_string".

   This command generates a pair of Propeller profiles:
   "<propeller_profile_prefix>_cc_profile.txt" and
   "<propeller_profile_prefix>_ld_profile.txt".

6) Rebuild the kernel using the AutoFDO and Propeller profile files.
      CONFIG_AUTOFDO_CLANG=y
      CONFIG_PROPELLER_CLANG=y
   and
      $ make LLVM=1 CLANG_AUTOFDO_PROFILE=<autofdo_profile> \
        CLANG_PROPELLER_PROFILE_PREFIX=<propeller_profile_prefix>

Co-developed-by: Han Shen <shenhan@google.com>
Signed-off-by: Han Shen <shenhan@google.com>
Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Sriraman Tallam <tmsriram@google.com>
Suggested-by: Krzysztof Pszeniczny <kpszeniczny@google.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Stephane Eranian <eranian@google.com>
Tested-by: Yonghong Song <yonghong.song@linux.dev>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-11-27 09:38:27 +09:00
Linus Torvalds
5c00ff742b Merge tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:

 - The series "zram: optimal post-processing target selection" from
   Sergey Senozhatsky improves zram's post-processing selection
   algorithm. This leads to improved memory savings.

 - Wei Yang has gone to town on the mapletree code, contributing several
   series which clean up the implementation:
	- "refine mas_mab_cp()"
	- "Reduce the space to be cleared for maple_big_node"
	- "maple_tree: simplify mas_push_node()"
	- "Following cleanup after introduce mas_wr_store_type()"
	- "refine storing null"

 - The series "selftests/mm: hugetlb_fault_after_madv improvements" from
   David Hildenbrand fixes this selftest for s390.

 - The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng
   implements some rationaizations and cleanups in the page mapping
   code.

 - The series "mm: optimize shadow entries removal" from Shakeel Butt
   optimizes the file truncation code by speeding up the handling of
   shadow entries.

 - The series "Remove PageKsm()" from Matthew Wilcox completes the
   migration of this flag over to being a folio-based flag.

 - The series "Unify hugetlb into arch_get_unmapped_area functions" from
   Oscar Salvador implements a bunch of consolidations and cleanups in
   the hugetlb code.

 - The series "Do not shatter hugezeropage on wp-fault" from Dev Jain
   takes away the wp-fault time practice of turning a huge zero page
   into small pages. Instead we replace the whole thing with a THP. More
   consistent cleaner and potentiall saves a large number of pagefaults.

 - The series "percpu: Add a test case and fix for clang" from Andy
   Shevchenko enhances and fixes the kernel's built in percpu test code.

 - The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett
   optimizes mremap() by avoiding doing things which we didn't need to
   do.

 - The series "Improve the tmpfs large folio read performance" from
   Baolin Wang teaches tmpfs to copy data into userspace at the folio
   size rather than as individual pages. A 20% speedup was observed.

 - The series "mm/damon/vaddr: Fix issue in
   damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON
   splitting.

 - The series "memcg-v1: fully deprecate charge moving" from Shakeel
   Butt removes the long-deprecated memcgv2 charge moving feature.

 - The series "fix error handling in mmap_region() and refactor" from
   Lorenzo Stoakes cleanup up some of the mmap() error handling and
   addresses some potential performance issues.

 - The series "x86/module: use large ROX pages for text allocations"
   from Mike Rapoport teaches x86 to use large pages for
   read-only-execute module text.

 - The series "page allocation tag compression" from Suren Baghdasaryan
   is followon maintenance work for the new page allocation profiling
   feature.

 - The series "page->index removals in mm" from Matthew Wilcox remove
   most references to page->index in mm/. A slow march towards shrinking
   struct page.

 - The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs
   interface tests" from Andrew Paniakin performs maintenance work for
   DAMON's self testing code.

 - The series "mm: zswap swap-out of large folios" from Kanchana Sridhar
   improves zswap's batching of compression and decompression. It is a
   step along the way towards using Intel IAA hardware acceleration for
   this zswap operation.

 - The series "kasan: migrate the last module test to kunit" from
   Sabyrzhan Tasbolatov completes the migration of the KASAN built-in
   tests over to the KUnit framework.

 - The series "implement lightweight guard pages" from Lorenzo Stoakes
   permits userapace to place fault-generating guard pages within a
   single VMA, rather than requiring that multiple VMAs be created for
   this. Improved efficiencies for userspace memory allocators are
   expected.

 - The series "memcg: tracepoint for flushing stats" from JP Kobryn uses
   tracepoints to provide increased visibility into memcg stats flushing
   activity.

 - The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky
   fixes a zram buglet which potentially affected performance.

 - The series "mm: add more kernel parameters to control mTHP" from
   Maíra Canal enhances our ability to control/configuremultisize THP
   from the kernel boot command line.

 - The series "kasan: few improvements on kunit tests" from Sabyrzhan
   Tasbolatov has a couple of fixups for the KASAN KUnit tests.

 - The series "mm/list_lru: Split list_lru lock into per-cgroup scope"
   from Kairui Song optimizes list_lru memory utilization when lockdep
   is enabled.

* tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (215 commits)
  cma: enforce non-zero pageblock_order during cma_init_reserved_mem()
  mm/kfence: add a new kunit test test_use_after_free_read_nofault()
  zram: fix NULL pointer in comp_algorithm_show()
  memcg/hugetlb: add hugeTLB counters to memcg
  vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event
  mm: mmap_lock: check trace_mmap_lock_$type_enabled() instead of regcount
  zram: ZRAM_DEF_COMP should depend on ZRAM
  MAINTAINERS/MEMORY MANAGEMENT: add document files for mm
  Docs/mm/damon: recommend academic papers to read and/or cite
  mm: define general function pXd_init()
  kmemleak: iommu/iova: fix transient kmemleak false positive
  mm/list_lru: simplify the list_lru walk callback function
  mm/list_lru: split the lock to per-cgroup scope
  mm/list_lru: simplify reparenting and initial allocation
  mm/list_lru: code clean up for reparenting
  mm/list_lru: don't export list_lru_add
  mm/list_lru: don't pass unnecessary key parameters
  kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller
  kasan: change kasan_atomics kunit test as KUNIT_CASE_SLOW
  kasan: use EXPORT_SYMBOL_IF_KUNIT to export symbols
  ...
2024-11-23 09:58:07 -08:00
Linus Torvalds
856385e0c5 Merge tag 'linux_kselftest-next-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull kselftest update from Shuah Khan:
 "timer test:
   - remove duplicate defines
   - fixes to improve error reporting

  rtc test:
   - check rtc alarm status in alarm test

  resctrl test:
   - add array overrun checks during iMC config parsing code and when
     reading strings
   - fixes and reorganizing code"

* tag 'linux_kselftest-next-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (23 commits)
  selftests/resctrl: Replace magic constants used as array size
  selftests/resctrl: Keep results from first test run
  selftests/resctrl: Do not compare performance counters and resctrl at low bandwidth
  selftests/resctrl: Use cache size to determine "fill_buf" buffer size
  selftests/resctrl: Ensure measurements skip initialization of default benchmark
  selftests/resctrl: Make benchmark parameter passing robust
  selftests/resctrl: Remove unused measurement code
  selftests/resctrl: Only support measured read operation
  selftests/resctrl: Remove "once" parameter required to be false
  selftests/resctrl: Make wraparound handling obvious
  selftests/resctrl: Protect against array overflow when reading strings
  selftests/resctrl: Protect against array overrun during iMC config parsing
  selftests/resctrl: Fix memory overflow due to unhandled wraparound
  selftests/resctrl: Print accurate buffer size as part of MBM results
  selftests/resctrl: Make functions only used in same file static
  selftests: Add a test mangling with uc_sigmask
  selftests: Rename sigaltstack to generic signal
  selftest: rtc: Add to check rtc alarm status for alarm related test
  selftests:timers: remove local CLOCKID defines
  selftests: timers: Remove unneeded semicolon
  ...
2024-11-20 11:54:39 -08:00
Linus Torvalds
c3cda60e83 Merge tag 'docs-6.13' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
 "Another moderately busy cycle in docsland:

   - Work on Chinese translations has picked up again. Happily, they are
     maintaining the existing translations and not just adding new ones.

   - Some maintenance of the Japanese and Italian translations as well.

   - The removal of the venerable "dontdiff" file. It has long outlived
     its usefulness and contained entries ("parse.*") that would
     actively mask actual source change.

   - The addition of enforcement information to the code-of-conduct
     documentation.

  Along with some build-system fixes and a lot of typo and language
  fixes"

* tag 'docs-6.13' of git://git.lwn.net/linux: (52 commits)
  Documentation/CoC: spell out enforcement for unacceptable behaviors
  docs: fix typos and whitespace in Documentation/process/backporting.rst
  docs/zh_CN: fix one sentence in llvm.rst
  docs: bug-bisect: add a note about bisecting -next
  docs/zh_CN: add the translation of kbuild/llvm.rst
  Documentation: Fix incorrect paths/magic in magic numbers rst
  Documentation/maintainer-tip: Fix typos
  Documentation: Improve crash_kexec_post_notifiers description
  Docs/zh_CN: Translate physical_memory.rst to Simplified Chinese
  Documentation: admin: reorganize kernel-parameters intro
  docs/zh_CN: update the translation of process/programming-language.rst
  docs/zh_CN: update the translation of mm/page_owner.rst
  docs/zh_CN: update the translation of mm/page_table_check.rst
  docs/zh_CN: update the translation of mm/overcommit-accounting.rst
  docs/zh_CN: update the translation of mm/admon/faq.rst
  docs/zh_CN: update the translation of mm/active_mm.rst
  docs/zh_CN: update the translation of mm/hmm.rst
  docs: remove Documentation/dontdiff
  docs/zh_CN: Add a entry in Chinese glossary
  Docs/zh_CN: Fix the pfn calculation error in page_tables.rst
  ...
2024-11-20 09:16:45 -08:00
Catalin Marinas
7591c127f3 kmemleak: iommu/iova: fix transient kmemleak false positive
The introduction of iova_depot_pop() in 911aa1245d ("iommu/iova: Make
the rcache depot scale better") confused kmemleak by moving a struct
iova_magazine object from a singly linked list to rcache->depot and
resetting the 'next' pointer referencing it.  Unlike doubly linked lists,
the content of the object being referred is never changed on removal from
a singly linked list and the kmemleak checksum heuristics do not detect
such scenario.  This leads to false positives like:

unreferenced object 0xffff8881a5301000 (size 1024):
  comm "softirq", pid 0, jiffies 4306297099 (age 462.991s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 e7 7d 05 00 00 00 00 00  .........}......
    0f b4 05 00 00 00 00 00 b4 96 05 00 00 00 00 00  ................
  backtrace:
    [<ffffffff819f5f08>] __kmem_cache_alloc_node+0x1e8/0x320
    [<ffffffff818a239a>] kmalloc_trace+0x2a/0x60
    [<ffffffff8231d31e>] free_iova_fast+0x28e/0x4e0
    [<ffffffff82310860>] fq_ring_free_locked+0x1b0/0x310
    [<ffffffff8231225d>] fq_flush_timeout+0x19d/0x2e0
    [<ffffffff813e95ba>] call_timer_fn+0x19a/0x5c0
    [<ffffffff813ea16b>] __run_timers+0x78b/0xb80
    [<ffffffff813ea5bd>] run_timer_softirq+0x5d/0xd0
    [<ffffffff82f1d915>] __do_softirq+0x205/0x8b5

Introduce kmemleak_transient_leak() which resets the object checksum
requiring another scan pass before it is reported (if still unreferenced).
Call this new API in iova_depot_pop().

Link: https://lkml.kernel.org/r/20241104111944.2207155-1-catalin.marinas@arm.com
Link: https://lore.kernel.org/r/ZY1osaGLyT-sdKE8@shredder/
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Ido Schimmel <idosch@idosch.org>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-11 17:22:26 -08:00
Sabyrzhan Tasbolatov
4e4d9c72c9 kasan: delete CONFIG_KASAN_MODULE_TEST
Since we've migrated all tests to the KUnit framework, we can delete
CONFIG_KASAN_MODULE_TEST and mentioning of it in the documentation as
well.

I've used the online translator to modify the non-English documentation.

[snovitoll@gmail.com: fix indentation in translation]
  Link: https://lkml.kernel.org/r/20241020042813.3223449-1-snovitoll@gmail.com
Link: https://lkml.kernel.org/r/20241016131802.3115788-4-snovitoll@gmail.com
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-11 00:26:44 -08:00
Rong Xu
315ad8780a kbuild: Add AutoFDO support for Clang build
Add the build support for using Clang's AutoFDO. Building the kernel
with AutoFDO does not reduce the optimization level from the
compiler. AutoFDO uses hardware sampling to gather information about
the frequency of execution of different code paths within a binary.
This information is then used to guide the compiler's optimization
decisions, resulting in a more efficient binary. Experiments
showed that the kernel can improve up to 10% in latency.

The support requires a Clang compiler after LLVM 17. This submission
is limited to x86 platforms that support PMU features like LBR on
Intel machines and AMD Zen3 BRS. Support for SPE on ARM 1,
 and BRBE on ARM 1 is part of planned future work.

Here is an example workflow for AutoFDO kernel:

1) Build the kernel on the host machine with LLVM enabled, for example,
       $ make menuconfig LLVM=1
    Turn on AutoFDO build config:
      CONFIG_AUTOFDO_CLANG=y
    With a configuration that has LLVM enabled, use the following
    command:
       scripts/config -e AUTOFDO_CLANG
    After getting the config, build with
      $ make LLVM=1

2) Install the kernel on the test machine.

3) Run the load tests. The '-c' option in perf specifies the sample
   event period. We suggest     using a suitable prime number,
   like 500009, for this purpose.
   For Intel platforms:
      $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c <count> \
        -o <perf_file> -- <loadtest>
   For AMD platforms:
      The supported system are: Zen3 with BRS, or Zen4 with amd_lbr_v2
     For Zen3:
      $ cat proc/cpuinfo | grep " brs"
      For Zen4:
      $ cat proc/cpuinfo | grep amd_lbr_v2
      $ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a \
        -N -b -c <count> -o <perf_file> -- <loadtest>

4) (Optional) Download the raw perf file to the host machine.

5) To generate an AutoFDO profile, two offline tools are available:
   create_llvm_prof and llvm_profgen. The create_llvm_prof tool is part
   of the AutoFDO project and can be found on GitHub
   (https://github.com/google/autofdo), version v0.30.1 or later. The
   llvm_profgen tool is included in the LLVM compiler itself. It's
   important to note that the version of llvm_profgen doesn't need to
   match the version of Clang. It needs to be the LLVM 19 release or
   later, or from the LLVM trunk.
      $ llvm-profgen --kernel --binary=<vmlinux> --perfdata=<perf_file> \
        -o <profile_file>
   or
      $ create_llvm_prof --binary=<vmlinux> --profile=<perf_file> \
        --format=extbinary --out=<profile_file>

   Note that multiple AutoFDO profile files can be merged into one via:
      $ llvm-profdata merge -o <profile_file>  <profile_1> ... <profile_n>

6) Rebuild the kernel using the AutoFDO profile file with the same config
   as step 1, (Note CONFIG_AUTOFDO_CLANG needs to be enabled):
      $ make LLVM=1 CLANG_AUTOFDO_PROFILE=<profile_file>

Co-developed-by: Han Shen <shenhan@google.com>
Signed-off-by: Han Shen <shenhan@google.com>
Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Sriraman Tallam <tmsriram@google.com>
Suggested-by: Krzysztof Pszeniczny <kpszeniczny@google.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Stephane Eranian <eranian@google.com>
Tested-by: Yonghong Song <yonghong.song@linux.dev>
Tested-by: Yabin Cui <yabinc@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Tested-by: Peter Jung <ptr1337@cachyos.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-11-06 22:41:09 +09:00
Nir Lichtman
6fde43859f Documentation: English fixes in kgdb/kdb article
Minor grammar and typos fixed in the kgdb/kdb article

Signed-off-by: Nir Lichtman <nir@lichtman.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241018223536.GA799515@lichtman.org
2024-10-21 09:30:56 -06:00
Haoyang Liu
3f53d1b4a4 docs/dev-tools: fix a typo
fix a typo in dev-tools/kmsan.rst

[jc: this is not really a typo, but "iff" is clearly a confusing construct
for non-native speakers; changing it will prevent people from trying to
"fix" it repeatedly.]

Signed-off-by: Haoyang Liu <tttturtleruss@hust.edu.cn>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241015140159.8082-1-tttturtleruss@hust.edu.cn
2024-10-17 09:39:19 -06:00
Anna-Maria Behnsen
6534086aa6 checkpatch: Remove links to outdated documentation
checkpatch.pl checks for several things related to sleep and delay
functions. In all warnings the outdated documentation is referenced. Also
in checkpatch kernel documentation the outdated documentation is
referenced.

Replace the links to the outdated documentation with links to the function
description.

Note: Update of the outdated checkpatch checks is done in a second step.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241014-devel-anna-maria-b4-timers-flseep-v3-10-dc8b907cb62f@linutronix.de
2024-10-16 00:36:47 +02:00
Nícolas F. R. A. Prado
c9949b51d0 docs: dev-tools: Add documentation for the device focused kselftests
Add documentation for the kselftests focused on testing devices and
point to it from the kselftest documentation. There are multiple tests
in this category so the aim of this page is to make it clear when to run
each test.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2024-10-14 16:15:13 -06:00
Changhuang Liang
3c8ead6f70 Documentation: kgdb: Correct parameter error
Module kgdb had been converted to debug_core since commit c433820971
("Move kernel/kgdb.c to kernel/debug/debug_core.c") be added, so let's
correct the module parameter path.

Fixes: c433820971 ("Move kernel/kgdb.c to kernel/debug/debug_core.c")
Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240925100742.1730576-1-changhuang.liang@starfivetech.com
2024-10-07 11:50:54 -06:00
Matthieu Baerts (NGI0)
d260f6150d docs: gcov: fix link to LCOV website
The previous website hosted on SourceForge is no longer available since
January 2024 according to archive.org [1].

It looks like the website has been officially moved to GitHub in June
2022 [2]. Best to redirect readers to the new location then.

Link: https://web.archive.org/web/20240105235756/https://ltp.sourceforge.net/coverage/lcov.php [1]
Link: https://github.com/linux-test-project/lcov/commit/6da8399c7a7a [2]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240926-doc-fix-lcov-link-v1-1-46f250cb7173@kernel.org
2024-10-07 11:50:54 -06:00
Linus Torvalds
9ab27b0186 Merge tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
Pull clk updates from Stephen Boyd:
 "The core clk framework is left largely untouched this time around
  except for support for the newly ratified DT property
  'assigned-clock-rates-u64'.

  I'm much more excited about the support for loading DT overlays from
  KUnit tests so that we can test how the clk framework parses DT nodes
  during clk registration. The clk framework has some places that are
  highly DeviceTree dependent so this charts the path to extend the
  KUnit tests to cover even more framework code in the future. I've got
  some more tests on the list that use the DT overlay support, but they
  uncovered issues with clk unregistration that I'm still working on
  fixing.

  Outside the core, the clk driver update pile is dominated by Qualcomm
  and Renesas SoCs, making it fairly usual. Looking closer, there are
  fixes for things all over the place, like adding missing clk
  frequencies or moving defines for the number of clks out of DT binding
  headers into the drivers. There are even conversions of DT bindings to
  YAML and migration away from strings to describe clk topology. Overall
  it doesn't look unusual so I expect the new drivers to be where we'll
  have fixes in the coming weeks.

  Core:
   - KUnit tests for clk registration and fixed rate basic clk type
   - A couple more devm helpers, one consumer and one provider
   - Support for assigned-clock-rates-u64

  New Drivers:
   - Camera, display and GPU clocks on Qualcomm SM4450
   - Camera clocks on Qualcomm SM8150
   - Rockchip rk3576 clks
   - Microchip SAM9X7 clks
   - Renesas RZ/V2H(P) (R9A09G057) clks

  Updates:
   - Mark a bunch of struct freq_tbl const to reduce .data usage
   - Add Qualcomm MSM8226 A7PLL and Regera PLL support
   - Fix the Qualcomm Lucid 5LPE PLL configuration sequence to not reuse
     Trion, as they do differ
   - A number of fixes to the Qualcomm SM8550 display clock driver
   - Fold Qualcomm SM8650 display clock driver into SM8550 one
   - Add missing clocks and GDSCs needed for audio on Qualcomm MSM8998
   - Add missing USB MP resets, GPLL9, and QUPv3 DFS to Qualcomm SC8180X
   - Fix sdcc clk frequency tables on Qualcomm SC8180X
   - Drop the Qualcomm SM8150 gcc_cpuss_ahb_clk_src
   - Mark Qualcomm PCIe GDSCs as RET_ON on sm8250 and sm8540 to avoid
     them turning off during suspend
   - Use the HW_CTRL mechanism on Qualcomm SM8550 video clock controller
     GDSCs
   - Get rid of CLK_NR_CLKS defines in Rockchip DT binding headers
   - Some fixes for Rockchip rk3228 and rk3588
   - Exynos850: Add clock for Thermal Management Unit
   - Exynos7885: Fix duplicated ID in the header, add missing TOP PLLs
     and add clocks for USB block in the FSYS clock controller
   - ExynosAutov9: Add DPUM clock controller
   - ExynosAutov920: Add new (first) clock controllers: TOP and PERIC0
     (and a bit more complete bindings)
   - Use clk_hw pointer instead of fw_name for acm_aud_clk[0-1]_sel
     clocks on i.MX8Q as parents in ACM provider
   - Add i.MX95 NETCMIX support to the block control provider
   - Fix parents for ENETx_REF_SEL clocks on i.MX6UL
   - Add USB clocks, resets and power domains on Renesas RZ/G3S
   - Add Generic Timer (GTM), I2C Bus Interface (RIIC), SD/MMC Host
     Interface (SDHI) and Watchdog Timer (WDT) clocks and resets on
     Renesas RZ/V2H
   - Add PCIe, PWM, and CAN-FD clocks on Renesas R-Car V4M
   - Add LCD controller clocks and resets on Renesas RZ/G2UL
   - Add DMA clocks and resets on Renesas RZ/G3S
   - Add fractional multiplication PLL support on Renesas R-Car Gen4
   - Document support for the Renesas RZ/G2M v3.0 (r8a774a3) SoC
   - Support for the Microchip SAM9X7 SoC as follows:
   - Updates for the Microchip PLL drivers
   - DT binding documentation updates (for the new clock driver and for
     the slow clock controller that SAM9X7 is using)
   - A fix for the Microchip SAMA7G5 clock driver to avoid allocating
     more memory than necessary
   - Constify some Amlogic structs
   - Add SM1 eARC clocks for Amlogic
   - Introduce a symbol namespace for Amlogic clock specific symbols
   - Add reset controller support to audiomix block control on i.MX
   - Add CLK_SET_RATE_PARENT flag to all audiomix clocks and to i.MX7D
     lcdif_pixel_src clock
   - Fix parent clocks for earc_phy and audpll on i.MX8MP
   - Fix default parents for enet[12]_ref_sel on i.MX6UL
   - Add ops in composite 8M and 93 that allow no-op on disable
   - Add check for PCC present bit on composite 7ULP register
   - Fix fractional part for fracn-gppll on prepare in i.MX
   - Fix clock tree update for TF-A managed clocks on i.MX8M
   - Drop CLK_SET_PARENT_GATE for DRAM mux on i.MX7D
   - Add the SAI7 IPG clock for i.MX8MN
   - Mark the 'nand_usdhc_bus' clock as non-critical on i.MX8MM
   - Add LVDS bypass clocks on i.MX8QXP
   - Add muxes for MIPI and PHY ref clocks on i.MX
   - Reorder dc0_bypass0_clk, lcd_pxl and dc1_disp clocks on i.MX8QXP
   - Add 1039.5MHz and 800MHz rates to fracn-gppll table on i.MX
   - Add CLK_SET_RATE_PARENT for media_disp pixel clocks on i.MX8QXP
   - Add some module descriptions to the i.MX generic and the i.MXRT1050
     driver
   - Fix return value for bypass for composite i.MX7ULP
   - Move Mediatek clk bindings to clock/
   - Convert some more clk bindings to dt schema"

* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: (180 commits)
  clk: Switch back to struct platform_driver::remove()
  dt-bindings: clock, reset: fix top-comment indentation rk3576 headers
  clk: rockchip: remove unused mclk_pdm0_p/pdm0_p definitions
  clk: provide devm_clk_get_optional_enabled_with_rate()
  clk: fixed-rate: add devm_clk_hw_register_fixed_rate_parent_data()
  clk: imx6ul: fix clock parent for IMX6UL_CLK_ENETx_REF_SEL
  clk: renesas: r9a09g057: Add clock and reset entries for GTM/RIIC/SDHI/WDT
  clk: renesas: rzv2h: Add support for dynamic switching divider clocks
  clk: renesas: r9a08g045: Add clocks, resets and power domains for USB
  clk: rockchip: fix error for unknown clocks
  clk: rockchip: rk3588: drop unused code
  clk: rockchip: Add clock controller for the RK3576
  clk: rockchip: Add new pll type pll_rk3588_ddr
  dt-bindings: clock, reset: Add support for rk3576
  dt-bindings: clock: rockchip,rk3588-cru: drop unneeded assigned-clocks
  clk: rockchip: rk3588: Fix 32k clock name for pmu_24m_32k_100m_src_p
  clk: imx95: enable the clock of NETCMIX block control
  dt-bindings: clock: add RMII clock selection
  dt-bindings: clock: add i.MX95 NETCMIX block control
  clk: imx: imx8: Use clk_hw pointer for self registered clock in clk_parent_data
  ...
2024-09-23 15:01:48 -07:00
Linus Torvalds
617a814f14 Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
 "Along with the usual shower of singleton patches, notable patch series
  in this pull request are:

   - "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
     consistency to the APIs and behaviour of these two core allocation
     functions. This also simplifies/enables Rustification.

   - "Some cleanups for shmem" from Baolin Wang. No functional changes -
     mode code reuse, better function naming, logic simplifications.

   - "mm: some small page fault cleanups" from Josef Bacik. No
     functional changes - code cleanups only.

   - "Various memory tiering fixes" from Zi Yan. A small fix and a
     little cleanup.

   - "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
     simplifications and .text shrinkage.

   - "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
     Butt. This is a feature, it adds new feilds to /proc/vmstat such as

       $ grep kstack /proc/vmstat
       kstack_1k 3
       kstack_2k 188
       kstack_4k 11391
       kstack_8k 243
       kstack_16k 0

     which tells us that 11391 processes used 4k of stack while none at
     all used 16k. Useful for some system tuning things, but
     partivularly useful for "the dynamic kernel stack project".

   - "kmemleak: support for percpu memory leak detect" from Pavel
     Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.

   - "mm: memcg: page counters optimizations" from Roman Gushchin. "3
     independent small optimizations of page counters".

   - "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
     David Hildenbrand. Improves PTE/PMD splitlock detection, makes
     powerpc/8xx work correctly by design rather than by accident.

   - "mm: remove arch_make_page_accessible()" from David Hildenbrand.
     Some folio conversions which make arch_make_page_accessible()
     unneeded.

   - "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
     Finkel. Cleans up and fixes our handling of the resetting of the
     cgroup/process peak-memory-use detector.

   - "Make core VMA operations internal and testable" from Lorenzo
     Stoakes. Rationalizaion and encapsulation of the VMA manipulation
     APIs. With a view to better enable testing of the VMA functions,
     even from a userspace-only harness.

   - "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
     issues in the zswap global shrinker, resulting in improved
     performance.

   - "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
     in some missing info in /proc/zoneinfo.

   - "mm: replace follow_page() by folio_walk" from David Hildenbrand.
     Code cleanups and rationalizations (conversion to folio_walk())
     resulting in the removal of follow_page().

   - "improving dynamic zswap shrinker protection scheme" from Nhat
     Pham. Some tuning to improve zswap's dynamic shrinker. Significant
     reductions in swapin and improvements in performance are shown.

   - "mm: Fix several issues with unaccepted memory" from Kirill
     Shutemov. Improvements to the new unaccepted memory feature,

   - "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
     DAX PUDs. This was missing, although nobody seems to have notied
     yet.

   - "Introduce a store type enum for the Maple tree" from Sidhartha
     Kumar. Cleanups and modest performance improvements for the maple
     tree library code.

   - "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
     more cgroup v1 remnants away from the v2 memcg code.

   - "memcg: initiate deprecation of v1 features" from Shakeel Butt.
     Adds various warnings telling users that memcg v1 features are
     deprecated.

   - "mm: swap: mTHP swap allocator base on swap cluster order" from
     Chris Li. Greatly improves the success rate of the mTHP swap
     allocation.

   - "mm: introduce numa_memblks" from Mike Rapoport. Moves various
     disparate per-arch implementations of numa_memblk code into generic
     code.

   - "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
     improves the performance of munmap() of swap-filled ptes.

   - "support large folio swap-out and swap-in for shmem" from Baolin
     Wang. With this series we no longer split shmem large folios into
     simgle-page folios when swapping out shmem.

   - "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
     performance improvements and code reductions for gigantic folios.

   - "support shmem mTHP collapse" from Baolin Wang. Adds support for
     khugepaged's collapsing of shmem mTHP folios.

   - "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
     performance regression due to the addition of mseal().

   - "Increase the number of bits available in page_type" from Matthew
     Wilcox. Increases the number of bits available in page_type!

   - "Simplify the page flags a little" from Matthew Wilcox. Many legacy
     page flags are now folio flags, so the page-based flags and their
     accessors/mutators can be removed.

   - "mm: store zero pages to be swapped out in a bitmap" from Usama
     Arif. An optimization which permits us to avoid writing/reading
     zero-filled zswap pages to backing store.

   - "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
     window which occurs when a MAP_FIXED operqtion is occurring during
     an unrelated vma tree walk.

   - "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
     the vma_merge() functionality, making ot cleaner, more testable and
     better tested.

   - "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
     Minor fixups of DAMON selftests and kunit tests.

   - "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
     Code cleanups and folio conversions.

   - "Shmem mTHP controls and stats improvements" from Ryan Roberts.
     Cleanups for shmem controls and stats.

   - "mm: count the number of anonymous THPs per size" from Barry Song.
     Expose additional anon THP stats to userspace for improved tuning.

   - "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
     folio conversions and removal of now-unused page-based APIs.

   - "replace per-quota region priorities histogram buffer with
     per-context one" from SeongJae Park. DAMON histogram
     rationalization.

   - "Docs/damon: update GitHub repo URLs and maintainer-profile" from
     SeongJae Park. DAMON documentation updates.

   - "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
     improve related doc and warn" from Jason Wang: fixes usage of page
     allocator __GFP_NOFAIL and GFP_ATOMIC flags.

   - "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
     This was overprovisioning THPs in sparsely accessed memory areas.

   - "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
     Add support for zram run-time compression algorithm tuning.

   - "mm: Care about shadow stack guard gap when getting an unmapped
     area" from Mark Brown. Fix up the various arch_get_unmapped_area()
     implementations to better respect guard areas.

   - "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
     of mem_cgroup_iter() and various code cleanups.

   - "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
     pfnmap support.

   - "resource: Fix region_intersects() vs add_memory_driver_managed()"
     from Huang Ying. Fix a bug in region_intersects() for systems with
     CXL memory.

   - "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
     a couple more code paths to correctly recover from the encountering
     of poisoned memry.

   - "mm: enable large folios swap-in support" from Barry Song. Support
     the swapin of mTHP memory into appropriately-sized folios, rather
     than into single-page folios"

* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
  zram: free secondary algorithms names
  uprobes: turn xol_area->pages[2] into xol_area->page
  uprobes: introduce the global struct vm_special_mapping xol_mapping
  Revert "uprobes: use vm_special_mapping close() functionality"
  mm: support large folios swap-in for sync io devices
  mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
  mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
  mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
  set_memory: add __must_check to generic stubs
  mm/vma: return the exact errno in vms_gather_munmap_vmas()
  memcg: cleanup with !CONFIG_MEMCG_V1
  mm/show_mem.c: report alloc tags in human readable units
  mm: support poison recovery from copy_present_page()
  mm: support poison recovery from do_cow_fault()
  resource, kunit: add test case for region_intersects()
  resource: make alloc_free_mem_region() works for iomem_resource
  mm: z3fold: deprecate CONFIG_Z3FOLD
  vfio/pci: implement huge_fault support
  mm/arm64: support large pfn mappings
  mm/x86: support large pfn mappings
  ...
2024-09-21 07:29:05 -07:00
Linus Torvalds
194fcd20eb Merge tag 'linux_kselftest-kunit-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull kunit updates from Shuah Khan:

 - a new int_pow test suite

 - documentation update to clarify filename best practices

 - kernel-doc fix for EXPORT_SYMBOL_IF_KUNIT

 - change to build compile_commands.json automatically instead of
   requiring a manual build

* tag 'linux_kselftest-kunit-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  lib/math: Add int_pow test suite
  kunit: tool: Build compile_commands.json
  kunit: Fix kernel-doc for EXPORT_SYMBOL_IF_KUNIT
  Documentation: KUnit: Update filename best practices
2024-09-17 16:52:24 +02:00
Linus Torvalds
d58db3f3a0 Merge tag 'docs-6.12' of git://git.lwn.net/linux
Pull documentation update from Jonathan Corbet:
 "Another relatively mundane cycle for docs:

   - The beginning of an EEVDF scheduler document

   - More Chinese translations

   - A rethrashing of our bisection documentation

  ...plus the usual array of smaller fixes, and more than the usual
  number of typo fixes"

* tag 'docs-6.12' of git://git.lwn.net/linux: (48 commits)
  Remove duplicate "and" in 'Linux NVMe docs.
  docs:filesystems: fix spelling and grammar mistakes
  docs:filesystem: fix mispelled words on autofs page
  docs:mm: fixed spelling and grammar mistakes on vmalloc kernel stack page
  Documentation: PCI: fix typo in pci.rst
  docs/zh_CN: add the translation of kbuild/gcc-plugins.rst
  docs/process: fix typos
  docs:mm: fix spelling mistakes in heterogeneous memory management page
  accel/qaic: Fix a typo
  docs/zh_CN: update the translation of security-bugs
  docs: block: Fix grammar and spelling mistakes in bfq-iosched.rst
  Documentation: Fix spelling mistakes
  Documentation/gpu: Fix typo in Documentation/gpu/komeda-kms.rst
  scripts: sphinx-pre-install: remove unnecessary double check for $cur_version
  Loongarch: KVM: Add KVM hypercalls documentation for LoongArch
  Documentation: Document the kernel flag bdev_allow_write_mounted
  docs: scheduler: completion: Update member of struct completion
  docs: kerneldoc-preamble.sty: Suppress extra spaces in CJK literal blocks
  docs: submitting-patches: Advertise b4
  docs: update dev-tools/kcsan.rst url about KTSAN
  ...
2024-09-17 16:44:08 +02:00
Haoyang Liu
72ffee678f docs: update dev-tools/kcsan.rst url about KTSAN
The KTSAN doc has moved to
https://github.com/google/kernel-sanitizers/blob/master/KTSAN.md.
Update the url in kcsan.rst accordingly.

Signed-off-by: Haoyang Liu <tttturtleruss@hust.edu.cn>
Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
Acked-by: Marco Elver <elver@google.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240725174632.23803-1-tttturtleruss@hust.edu.cn
2024-09-04 08:04:10 -06:00
Marco Elver
cc0a0f9855 kfence: introduce burst mode
Introduce burst mode, which can be configured with kfence.burst=$count,
where the burst count denotes the additional successive slab allocations
to be allocated through KFENCE for each sample interval.

The idea is that this can give developers an additional knob to make
KFENCE more aggressive when debugging specific issues of systems where
either rebooting or recompiling the kernel with KASAN is not possible.

Experiment: To assess the effectiveness of the new option, we randomly
picked a recent out-of-bounds [1] and use-after-free bug [2], each with a
reproducer provided by syzbot, that initially detected these bugs with
KASAN.  We then tried to reproduce the bugs with KFENCE below.

[1] Fixed by: 7c55b78818 ("jfs: xattr: fix buffer overflow for invalid xattr")
    https://syzkaller.appspot.com/bug?id=9d1b59d4718239da6f6069d3891863c25f9f24a2
[2] Fixed by: f8ad00f3fb ("l2tp: fix possible UAF when cleaning up tunnels")
    https://syzkaller.appspot.com/bug?id=4f34adc84f4a3b080187c390eeef60611fd450e1

The following KFENCE configs were compared. A pool size of 1023 objects
was used for all configurations.

	Baseline
		kfence.sample_interval=100
		kfence.skip_covered_thresh=75
		kfence.burst=0

	Aggressive
		kfence.sample_interval=1
		kfence.skip_covered_thresh=10
		kfence.burst=0

	AggressiveBurst
		kfence.sample_interval=1
		kfence.skip_covered_thresh=10
		kfence.burst=1000

Each reproducer was run 10 times (after a fresh reboot), with the
following detection counts for each KFENCE config:

                    | Detection Count out of 10 |
                    |    OOB [1]  |    UAF [2]  |
  ------------------+-------------+-------------+
  Default           |     0/10    |     0/10    |
  Aggressive        |     0/10    |     0/10    |
  AggressiveBurst   |     8/10    |     8/10    |

With the Default and even the Aggressive configs the results are
unsurprising, given KFENCE has not been designed for deterministic bug
detection of small test cases.

However, when enabling burst mode with relatively large burst count,
KFENCE can start to detect heap memory-safety bugs even in simpler test
cases with high probability (in the above cases with ~80% probability).

Link: https://lkml.kernel.org/r/20240805124203.2692278-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:03 -07:00
Kees Cook
1757cc292a Documentation: KUnit: Update filename best practices
Based on feedback from Linus[1] and follow-up discussions, change the
suggested file naming for KUnit tests.

Link: https://lore.kernel.org/lkml/CAHk-=wgim6pNiGTBMhP8Kd3tsB7_JTAuvNJ=XYd3wPvvk=OHog@mail.gmail.com/ [1]
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Kees Cook <kees@kernel.org>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2024-08-26 06:57:28 -06:00
Vegard Nossum
3ade6ce125 selftests: rds: add testing infrastructure
This adds some basic self-testing infrastructure for RDS-TCP.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-09 13:18:46 +01:00