Add a mostly finished document describing how to report issues with the
Linux kernel to its developers. It is designed to be a lot more straight
forward and easier to follow than the current text about this
(Documentation/admin-guide/reporting-bugs.rst); at the same time the new
text should be more helpful for people unfamiliar with the topic, as it
provides a lot more details, too.
The main work on the text is done, but some polishing is still needed.
The text also needs to be reviewed by more people and a few issues still
might need some discussion. To make these tasks easier, it was decided
([1]) to add this document to the kernel sources in parallel to the
existing text; the latter will be removed once this text is considered
good enough(tm).
This document is quite long and provides a lot of details, but was
carefully crafted to make sure it's can also serve people that are in a
hurry. That's mainly achieved by having a TDLR and a step-by-step guide,
which should be good enough for quite a lot of people. Everybody that
wants or need more explanations can find them in a reference section,
which describes all the needed steps in detail.
Thanks to this structure the text can work for kernel developers that
just need to look something up, experienced FLOSS contributors that are
unfamiliar with the kernel's bug reporting workflow, and users reporting
something upstream for the first time. The text is thus a bit like the
kernel itself, which works well for embedded machines, a typical desktop
PC, cloud servers, and HPC.
The document was written in the hope it will improve the quality of the
bug reports, especially those that come from people unfamiliar with how
Linux kernel development works. Sadly quite a few reports from this
group are currently of poor quality and/or get submitted to the wrong
place. Part of the problem is the old reporting-bugs document, as it
makes its essence hard to grasp; it's and also inaccurate and slightly
outdated in a few spots. Due to this quite a few valid reports are
ignored in the end, which is annoying for those that compiled them and
bad for the kernel's quality.
The document near the top points out that it's still unfinished, but
nevertheless ready for consumption. Those few areas in the text that
might need some further discussion contain a note pointing this out.
Besides lack of review from core developers there is only one major
issue left: the section 'Decode failure message' is known to be
outdated: it's waiting for someone familiar with the topic to write
something up or give at least provide some hints and pointers what to
write there.
The new document is dual-licensed under GPL-2.0+ or CC-BY-4.0. The
latter is way more liberal and makes it attractive to use this text as a
base when writing about this topic on websites or in books. This
hopefully increases the chances that such texts are accurate and stick
to official way of doing things.
[1] https://lkml.kernel.org/r/20201118172958.5b014a44@lwn.net
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/e2db808f954744b79f10937a923d9c99bdca1fca.1607063223.git.linux@leemhuis.info
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This cleans up a few titles with extra colons, and removes the
reference to kernel 2.2. The docs don't yet cover *all* of 5.10 or
5.11, but I think they're close enough. Most entries are documented,
and have been checked against current kernels.
Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20201208074922.30359-1-steve@sk2.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Changeset 6b80975c63 ("scripts: kernel-doc: fix typedef parsing")
added support for things like:
typedef unsigned long foo();
However, it caused a regression on this prototype:
typedef bool v4l2_check_dv_timings_fnc(const struct v4l2_dv_timings *t, void *handle);
This is only noticed after adding a patch that checks if the
kernel-doc identifier matches the typedef:
./scripts/kernel-doc -none $(git grep '^.. kernel-doc::' Documentation/ |cut -d ' ' -f 3|sort|uniq) 2>&1|grep expecting
include/media/v4l2-dv-timings.h:38: warning: expecting prototype for typedef v4l2_check_dv_timings_fnc. Prototype was for typedef nc instead
The problem is that, with the new parsing logic, it is not
checking for complete words at the type part.
Fix it by adding a \b at the end of each type word at the
regex.
fixes: 6b80975c63 ("scripts: kernel-doc: fix typedef parsing")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/218ff56dcb8e73755005d3fb64586eb1841a276b.1606896997.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add support for the same output format as the bash script,
and use its implementation instead of the previous one.
I opted to do such patch in order to have a single script
responsible for parsing Documentation/features and
produce different outputs.
As someone may rely on the past format, which is easy
to parse it, get_feat.pl now gains a new command with
the same output format as the previous script.
As a side effect, the perl script is a lot faster, as it reads
each file only once, instead of parsing files several times
via a for command and grep commands inside it.
This patch also changes the features list order to be
case-insensitive, in order to better match the output of
the existing script.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/a97f49677805ad4e6b982d02c0db8c9dfbbd20a6.1606748711.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The Documentation/features contains a set of parseable files.
It is not worth converting them to ReST format, as they're
useful the way it is. It is, however, interesting to parse
them and produce output on different formats:
1) Output the contents of a feature in ReST format;
2) Output what features a given architecture supports;
3) Output a matrix with features x architectures.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/8b0c1ad06d689283a6d78c4ccd188a02c3acc0de.1606748711.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Sphinx 3.1 introduced namespaces for C cross-references. With this,
each C domain type/function declaration is put inside the namespace that
was active at the time of its declaration.
Add support for automatic cross-referencing inside C namespaces by
checking whether the corresponding source file had a C namespace Sphinx
directive, and if so, try cross-referencing inside of it before going to
the global scope.
This assumes there's only one namespace (if any) per rst file.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Link: https://lore.kernel.org/r/20201117021107.214704-1-nfraprado@protonmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Currently, we do not have any documentation on commit reverts regarding
the requirement of Signed-off-by tag for it. This may be misleading to
the users.
Evaluating MISSING_SIGN_OFF checkpatch warnings on v4.13..v5.8 showed
that 4 out of 11 cases missing a sign-off are revert commits.
Add documentation regarding the same to document the community
consensus and let readers know.
Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
Link: https://lore.kernel.org/r/20201110174749.32068-1-yashsri421@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Pull driver core documentation fixes from Greg KH:
"Some small Documentation fixes that were fallout from the larger
documentation update we did in 5.10-rc2.
Nothing major here at all, but all of these have been in linux-next
and resolve build warnings when building the documentation files"
* tag 'driver-core-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
Documentation: remove mic/index from misc-devices/index.rst
scripts: get_api.pl: Add sub-titles to ABI output
scripts: get_abi.pl: Don't let ABI files to create subtitles
docs: leds: index.rst: add a missing file
docs: ABI: sysfs-class-net: fix a typo
docs: ABI: sysfs-driver-dma-ioatdma: what starts with /sys
Pull tty/serial fixes from Greg KH:
"Here are a small number of small tty and serial fixes for some
reported problems for the tty core, vt code, and some serial drivers.
They include fixes for:
- a buggy and obsolete vt font ioctl removal
- 8250_mtk serial baudrate runtime warnings
- imx serial earlycon build configuration fix
- txx9 serial driver error path cleanup issues
- tty core fix in release_tty that can be triggered by trying to bind
an invalid serial port name to a speakup console device
Almost all of these have been in linux-next without any problems, the
only one that hasn't, just deletes code :)"
* tag 'tty-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
vt: Disable KD_FONT_OP_COPY
tty: fix crash in release_tty if tty->port is not set
serial: txx9: add missing platform_driver_unregister() on error in serial_txx9_init
tty: serial: imx: enable earlycon by default if IMX_SERIAL_CONSOLE is enabled
serial: 8250_mtk: Fix uart_get_baud_rate warning
Pull USB fixes from Greg KH:
"Here are some small USB fixes and new device ids:
- USB gadget fixes for some reported issues
- Fixes for the ever-troublesome apple fastcharge driver, hopefully
we finally have it right.
- More USB core quirks for odd devices
- USB serial driver fixes for some long-standing issues that were
recently found
- some new USB serial driver device ids
All have been in linux-next with no reported issues"
* tag 'usb-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
USB: apple-mfi-fastcharge: fix reference leak in apple_mfi_fc_set_property
usb: mtu3: fix panic in mtu3_gadget_stop()
USB: serial: option: add Telit FN980 composition 0x1055
USB: serial: option: add LE910Cx compositions 0x1203, 0x1230, 0x1231
USB: serial: cyberjack: fix write-URB completion race
USB: Add NO_LPM quirk for Kingston flash drive
USB: serial: option: add Quectel EC200T module support
usb: raw-gadget: fix memory leak in gadget_setup
usb: dwc2: Avoid leaving the error_debugfs label unused
usb: dwc3: ep0: Fix delay status handling
usb: gadget: fsl: fix null pointer checking
usb: gadget: goku_udc: fix potential crashes in probe
usb: dwc3: pci: add support for the Intel Alder Lake-S
current->group_leader->exit_signal may change during copy_process() if
current->real_parent exits.
Move the assignment inside tasklist_lock to avoid the race.
Signed-off-by: Eddy Wu <eddy_wu@trendmicro.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's buggy:
On Fri, Nov 06, 2020 at 10:30:08PM +0800, Minh Yuan wrote:
> We recently discovered a slab-out-of-bounds read in fbcon in the latest
> kernel ( v5.10-rc2 for now ). The root cause of this vulnerability is that
> "fbcon_do_set_font" did not handle "vc->vc_font.data" and
> "vc->vc_font.height" correctly, and the patch
> <https://lkml.org/lkml/2020/9/27/223> for VT_RESIZEX can't handle this
> issue.
>
> Specifically, we use KD_FONT_OP_SET to set a small font.data for tty6, and
> use KD_FONT_OP_SET again to set a large font.height for tty1. After that,
> we use KD_FONT_OP_COPY to assign tty6's vc_font.data to tty1's vc_font.data
> in "fbcon_do_set_font", while tty1 retains the original larger
> height. Obviously, this will cause an out-of-bounds read, because we can
> access a smaller vc_font.data with a larger vc_font.height.
Further there was only one user ever.
- Android's loadfont, busybox and console-tools only ever use OP_GET
and OP_SET
- fbset documentation only mentions the kernel cmdline font: option,
not anything else.
- systemd used OP_COPY before release 232 published in Nov 2016
Now unfortunately the crucial report seems to have gone down with
gmane, and the commit message doesn't say much. But the pull request
hints at OP_COPY being broken
https://github.com/systemd/systemd/pull/3651
So in other words, this never worked, and the only project which
foolishly every tried to use it, realized that rather quickly too.
Instead of trying to fix security issues here on dead code by adding
missing checks, fix the entire thing by removing the functionality.
Note that systemd code using the OP_COPY function ignored the return
value, so it doesn't matter what we're doing here really - just in
case a lone server somewhere happens to be extremely unlucky and
running an affected old version of systemd. The relevant code from
font_copy_to_all_vcs() in systemd was:
/* copy font from active VT, where the font was uploaded to */
cfo.op = KD_FONT_OP_COPY;
cfo.height = vcs.v_active-1; /* tty1 == index 0 */
(void) ioctl(vcfd, KDFONTOP, &cfo);
Note this just disables the ioctl, garbage collecting the now unused
callbacks is left for -next.
v2: Tetsuo found the old mail, which allowed me to find it on another
archive. Add the link too.
Acked-by: Peilin Ye <yepeilin.cs@gmail.com>
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
References: https://lists.freedesktop.org/archives/systemd-devel/2016-June/036935.html
References: https://github.com/systemd/systemd/pull/3651
Cc: Greg KH <greg@kroah.com>
Cc: Peilin Ye <yepeilin.cs@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://lore.kernel.org/r/20201108153806.3140315-1-daniel.vetter@ffwll.ch
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull xfs fixes from Darrick Wong:
- Fix an uninitialized struct problem
- Fix an iomap problem zeroing unwritten EOF blocks
- Fix some clumsy error handling when writeback fails on filesystems
with blocksize < pagesize
- Fix a retry loop not resetting loop variables properly
- Fix scrub flagging rtinherit inodes on a non-rt fs, since the kernel
actually does permit that combination
- Fix excessive page cache flushing when unsharing part of a file
* tag 'xfs-5.10-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: only flush the unshared range in xfs_reflink_unshare
xfs: fix scrub flagging rtinherit even if there is no rt device
xfs: fix missing CoW blocks writeback conversion retry
iomap: clean up writeback state logic on writepage error
iomap: support partial page discard on writeback block mapping failure
xfs: flush new eof page on truncate to avoid post-eof corruption
xfs: set xefi_discard when creating a deferred agfl free log intent item
