[ Upstream commit 6b219431037bf98c9efd49716aea9b68440477a3 ]
In order to debug the kernel successfully with gdb you need to run
'make scripts_gdb' nowadays.
This was changed with the following commit:
Commit 67274c083438340ad16c ("scripts/gdb: delay generation of gdb
constants.py")
In order to have a complete guide for beginners this remark
should be added to the offial documentation.
Signed-off-by: Jakob Koschel <jkl820.git@gmail.com>
Link: https://lore.kernel.org/r/20230112-documentation-gdb-v2-1-292785c43dc9@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Workaround missing struct_size() support by calculating the size manually.
(Upstream commit eec028c9386ed1a692aa01a85b55952202b41619.)
Patch series " kcov: collect coverage from usb and vhost", v3.
This patchset extends kcov to allow collecting coverage from backgound
kernel threads. This extension requires custom annotations for each of
the places where coverage collection is desired. This patchset
implements this for hub events in the USB subsystem and for vhost
workers. See the first patch description for details about the kcov
extension. The other two patches apply this kcov extension to USB and
vhost.
Examples of other subsystems that might potentially benefit from this
when custom annotations are added (the list is based on
process_one_work() callers for bugs recently reported by syzbot):
1. fs: writeback wb_workfn() worker,
2. net: addrconf_dad_work()/addrconf_verify_work() workers,
3. net: neigh_periodic_work() worker,
4. net/p9: p9_write_work()/p9_read_work() workers,
5. block: blk_mq_run_work_fn() worker.
These patches have been used to enable coverage-guided USB fuzzing with
syzkaller for the last few years, see the details here:
https://github.com/google/syzkaller/blob/master/docs/linux/external_fuzzing_usb.md
This patchset has been pushed to the public Linux kernel Gerrit
instance:
https://linux-review.googlesource.com/c/linux/kernel/git/torvalds/linux/+/1524
This patch (of 3):
Add background thread coverage collection ability to kcov.
With KCOV_ENABLE coverage is collected only for syscalls that are issued
from the current process. With KCOV_REMOTE_ENABLE it's possible to
collect coverage for arbitrary parts of the kernel code, provided that
those parts are annotated with kcov_remote_start()/kcov_remote_stop().
This allows to collect coverage from two types of kernel background
threads: the global ones, that are spawned during kernel boot in a
limited number of instances (e.g. one USB hub_event() worker thread is
spawned per USB HCD); and the local ones, that are spawned when a user
interacts with some kernel interface (e.g. vhost workers).
To enable collecting coverage from a global background thread, a unique
global handle must be assigned and passed to the corresponding
kcov_remote_start() call. Then a userspace process can pass a list of
such handles to the KCOV_REMOTE_ENABLE ioctl in the handles array field
of the kcov_remote_arg struct. This will attach the used kcov device to
the code sections, that are referenced by those handles.
Since there might be many local background threads spawned from
different userspace processes, we can't use a single global handle per
annotation. Instead, the userspace process passes a non-zero handle
through the common_handle field of the kcov_remote_arg struct. This
common handle gets saved to the kcov_handle field in the current
task_struct and needs to be passed to the newly spawned threads via
custom annotations. Those threads should in turn be annotated with
kcov_remote_start()/kcov_remote_stop().
Internally kcov stores handles as u64 integers. The top byte of a
handle is used to denote the id of a subsystem that this handle belongs
to, and the lower 4 bytes are used to denote the id of a thread instance
within that subsystem. A reserved value 0 is used as a subsystem id for
common handles as they don't belong to a particular subsystem. The
bytes 4-7 are currently reserved and must be zero. In the future the
number of bytes used for the subsystem or handle ids might be increased.
When a particular userspace process collects coverage by via a common
handle, kcov will collect coverage for each code section that is
annotated to use the common handle obtained as kcov_handle from the
current task_struct. However non common handles allow to collect
coverage selectively from different subsystems.
Link: http://lkml.kernel.org/r/e90e315426a384207edbec1d6aa89e43008e4caf.1572366574.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Change-Id: I868c4846a412bfbae16086017e113813571df377
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Bug: 147413187
commit 6807c84652 ("x86: Enable KASLR by default") enables KASLR
by default on x86. While KASLR will confuse gdb which resolve kernel
symbol address from symbol table of vmlinux. We should turn off KASLR for
kernel debugging.
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Reviewed-by: Kieran Bingham <kbingham@kernel.org>
Acked-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
commit 6807c84652 ("x86: Enable KASLR by default") enables KASLR
by default on x86. While KASLR will confuse gdb which resolve kernel
symbol address from symbol table of vmlinux. We should turn off KASLR for
kernel debugging.
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Pull Kselftest updates from Shuah Khan:
"This update consists of:
- TAP13 framework and changes to some tests to convert to TAP13.
Converting kselftest output to standard format will help identify
run to run differences and pin point failures easily. TAP13 format
has been in use for several years and the output is human friendly.
Please find the specification:
https://testanything.org/tap-version-13-specification.html
Credit goes to Tim Bird for recommending TAP13 as a suitable
format, and to Grag KH for kick starting the work with help from
Paul Elder and Alice Ferrazzi
The first phase of the TAp13 conversion is included in this update.
Future updates will include updates to rest of the tests.
- Masami Hiramatsu fixed ftrace to run on 4.9 stable kernels.
- Kselftest documnetation has been converted to ReST format. Document
now has a new home under Documentation/dev-tools.
- kselftest_harness.h is now available for general use as a result of
Mickaël Salaün's work.
- Several fixes to skip and/or fail tests gracefully on older
releases"
* tag 'linux-kselftest-4.13-rc1-update' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (48 commits)
selftests: membarrier: use ksft_* var arg msg api
selftests: breakpoints: breakpoint_test_arm64: convert test to use TAP13
selftests: breakpoints: step_after_suspend_test use ksft_* var arg msg api
selftests: breakpoint_test: use ksft_* var arg msg api
kselftest: add ksft_print_msg() function to output general information
kselftest: make ksft_* output functions variadic
selftests/capabilities: Fix the test_execve test
selftests: intel_pstate: add .gitignore
selftests: fix memory-hotplug test
selftests: add missing test name in memory-hotplug test
selftests: check percentage range for memory-hotplug test
selftests: check hot-pluggagble memory for memory-hotplug test
selftests: typo correction for memory-hotplug test
selftests: ftrace: Use md5sum to take less time of checking logs
tools/testing/selftests/sysctl: Add pre-check to the value of writes_strict
kselftest.rst: do some adjustments after ReST conversion
selftest/net/Makefile: Specify output with $(OUTPUT)
selftest/intel_pstate/aperf: Use LDLIBS instead of LDFLAGS
selftest/memfd/Makefile: Fix build error
selftests: lib: Skip tests on missing test modules
...
Kmemleak requires that vmalloc'ed objects have a minimum reference count
of 2: one in the corresponding vm_struct object and the other owned by
the vmalloc() caller. There are cases, however, where the original
vmalloc() returned pointer is lost and, instead, a pointer to vm_struct
is stored (see free_thread_stack()). Kmemleak currently reports such
objects as leaks.
This patch adds support for treating any surplus references to an object
as additional references to a specified object. It introduces the
kmemleak_vmalloc() API function which takes a vm_struct pointer and sets
its surplus reference passing to the actual vmalloc() returned pointer.
The __vmalloc_node_range() calling site has been modified accordingly.
Link: http://lkml.kernel.org/r/1495726937-23557-4-git-send-email-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull documentation updates from Jonathan Corbet:
"There has been a fair amount of activity in the docs tree this time
around. Highlights include:
- Conversion of a bunch of security documentation into RST
- The conversion of the remaining DocBook templates by The Amazing
Mauro Machine. We can now drop the entire DocBook build chain.
- The usual collection of fixes and minor updates"
* tag 'docs-4.13' of git://git.lwn.net/linux: (90 commits)
scripts/kernel-doc: handle DECLARE_HASHTABLE
Documentation: atomic_ops.txt is core-api/atomic_ops.rst
Docs: clean up some DocBook loose ends
Make the main documentation title less Geocities
Docs: Use kernel-figure in vidioc-g-selection.rst
Docs: fix table problems in ras.rst
Docs: Fix breakage with Sphinx 1.5 and upper
Docs: Include the Latex "ifthen" package
doc/kokr/howto: Only send regression fixes after -rc1
docs-rst: fix broken links to dynamic-debug-howto in kernel-parameters
doc: Document suitability of IBM Verse for kernel development
Doc: fix a markup error in coding-style.rst
docs: driver-api: i2c: remove some outdated information
Documentation: DMA API: fix a typo in a function name
Docs: Insert missing space to separate link from text
doc/ko_KR/memory-barriers: Update control-dependencies example
Documentation, kbuild: fix typo "minimun" -> "minimum"
docs: Fix some formatting issues in request-key.rst
doc: ReSTify keys-trusted-encrypted.txt
doc: ReSTify keys-request-key.txt
...
Do some minor adjustments after ReST conversion:
- On most documents, we use prepend a "$ " before
command line arguments;
- Prefer to use :: on the preceding line;
- Split a multi-paragraph description as such.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
The sparse-based checking for non-RCU accesses to RCU-protected pointers
has been around for a very long time, and it is now the only type of
sparse-based checking that is optional. This commit therefore makes
it unconditional.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
The automatic conversion didn't work too well for this file.
It added weird html blocks inside it, and did some weird
things for literals. Manually fix it, in order to present
a nice display at html/pdf outputs.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Use pandoc to convert documentation to ReST by calling
Documentation/sphinx/tmplcvt script.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Add documentation of -DCONFIG_SPARSE_RCU_POINTER.
I started to add documentation of -D__CHECK_ENDIAN__ as well, but
discovered I'm too late; that's now enabled by default.
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
We dropped __CHECK_ENDIAN__ so __bitwise__ is now an implementation
detail. People should use __bitwise everywhere.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Now that we don't have automatic syntax highlighting, use the code-block
directive with the explicitly selected language, where appropriate.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Add minimal conf.py and moved dev-tools/tools.rst to dev-tools/index.rst
makes the dev-tools folder buildable stand-alone. To build only this
folder run::
make SPHINXDIRS=dev-tools htmldocs
make SPHINXDIRS=dev-tools pdfdocs
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Some of the kmemleak_*() callbacks in memblock, bootmem, CMA convert a
physical address to a virtual one using __va(). However, such physical
addresses may sometimes be located in highmem and using __va() is
incorrect, leading to inconsistent object tracking in kmemleak.
The following functions have been added to the kmemleak API and they take
a physical address as the object pointer. They only perform the
corresponding action if the address has a lowmem mapping:
kmemleak_alloc_phys
kmemleak_free_part_phys
kmemleak_not_leak_phys
kmemleak_ignore_phys
The affected calling places have been updated to use the new kmemleak
API.
Link: http://lkml.kernel.org/r/1471531432-16503-1-git-send-email-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fold the sparse document into the development tools set; no changes to the
text itself beyond formatting.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This directory will be a collecting point for documentation oriented around
development tools. As a step toward ordering Documentation/ it's a small
one, but we have to start somewhere...
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
