Add rules for finding places where str_plural() can be used. This
currently finds:
54 files changed, 62 insertions(+), 61 deletions(-)
Co-developed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://lore.kernel.org/all/fc1b25a8-6381-47c2-831c-ab6b8201a82b@intel.com/
Signed-off-by: Kees Cook <keescook@chromium.org>
Commit ff82e84e80 ("coccinelle: device_attr_show: simplify patch case")
simplifies the patch case, as a result, STR is no longer needed.
This also helps to fix below coccicheck warning:
> warning: rp: metavariable STR not used in the - or context code
CC: Julia Lawall <Julia.Lawall@inria.fr>
CC: Nicolas Palix <nicolas.palix@imag.fr>
CC: cocci@inria.fr
Fixes: ff82e84e80 ("coccinelle: device_attr_show: simplify patch case")
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Replacing the final expression argument by ... allows the format
string to have multiple arguments.
It also has the advantage of allowing the change to be recognized as
a change in a single statement, thus avoiding adding unneeded braces.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
A common practice is to grep for "WARNING" or "ERROR" text in the report
output from a Coccinelle semantic patch script. So, include the text
"WARNING: " in the report output generated by the semantic patch for
desired filtering of the output. Also improves the readability of the
output. Here is an example of the old and new outputs reported:
xyz_file.c:131:39-40: atomic_add_unless
xyz_file.c:131:39-40: WARNING: atomic_add_unless
xyz_file.c:196:6-25: atomic_dec_and_test variation before object free at line 208.
xyz_file.c:196:6-25: WARNING: atomic_dec_and_test variation before object free at line 208.
Signed-off-by: Deepak R Varma <drv@mailo.com>
Acked-by: Julia Lawall <Julia.Lawall@inria.fr>
Commit 453431a549 ("mm, treewide: rename kzfree() to
kfree_sensitive()") renamed kzfree() to kfree_sensitive(),
it should be applied to coccinelle.
Signed-off-by: Weizhao Ouyang <o451686892@gmail.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Acked-by: Denis Efremov <efremov@linux.com>
Using kobj_to_dev() instead of container_of() is not universally
accepted among maintainers as an improvement. The warning leads to
repeated patch submissions that won't be accepted. Remove the script.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Denis Efremov <efremov@linux.com>
Cc: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Acked-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Denis Efremov <efremov@linux.com>
The ptr_ret script script addresses a number of situations where we end up
testing an error pointer, and if it's an error returning it, or return 0
otherwise to transform it into a PTR_ERR_OR_ZERO call.
So it will convert a block like this:
if (IS_ERR(err))
return PTR_ERR(err);
return 0;
into
return PTR_ERR_OR_ZERO(err);
While this is technically correct, it has a number of drawbacks. First, it
merges the error and success path, which will make it harder for a reviewer
or reader to grasp.
It's also more difficult to extend if we were to add some code between the
error check and the function return, making the author essentially revert
that patch before adding new lines, while it would have been a trivial
addition otherwise for the rewiever.
Therefore, since that script is only about cosmetic in the first place,
let's remove it since it's not worth it.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Julia Lawall <julia.lawall@inria.fr>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Check that alloc and free types of functions match each other.
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Print memset() call position in addition to the kfree() position to
ease issues identification.
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Commit dfd32cad14 ("dma-mapping: remove dma_zalloc_coherent()")
removed the definition of dma_zalloc_coherent() and also removed the
corresponding patch rule for replacing instances of dma_alloc_coherent +
memset in zalloc-simple.cocci (though left the report rule).
Add a new patch rule to remove unnecessary calls to memset after
allocating with dma_alloc_coherent. While we're at it, fix a couple of
typos.
Fixes: dfd32cad14 ("dma-mapping: remove dma_zalloc_coherent()")
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Add vmemdup_user() transformations to the memdup_user.cocci rule.
Commit 50fd2f298b ("new primitive: vmemdup_user()") introduced
vmemdup_user(). The function uses kvmalloc with GPF_USER flag.
Signed-off-by: Denis Efremov <efremov@linux.com>
Match GFP_USER and optional __GFP_NOWARN allocations with
memdup_user.cocci rule.
Commit 6c2c97a24f ("memdup_user(): switch to GFP_USER") switched
memdup_user() from GFP_KERNEL to GFP_USER. In almost all cases it
is still a good idea to recommend memdup_user() for GFP_KERNEL
allocations. The motivation behind altering memdup_user() to GFP_USER:
https://lkml.org/lkml/2018/1/6/333
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Check for memset()/memzero_explicit() followed by kfree()/vfree()/kvfree().
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
There is a typo in rule r2. Position p1 should be attached to kzalloc()
call.
Fixes: 29a36d4dec ("scripts/coccinelle: improve the coverage of some semantic patches")
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
According to the documentation[1] show() methods of device attributes
should return the number of bytes printed into the buffer. This is
the return value of scnprintf(). show() must not use snprintf()
when formatting the value to be returned to user space. snprintf()
returns the length the resulting string would be, assuming it all
fit into the destination array[2]. scnprintf() return the length of
the string actually created in buf. If one can guarantee that an
overflow will never happen sprintf() can be used otherwise scnprintf().
[1] Documentation/filesystems/sysfs.txt
[2] "snprintf() confusion" https://lwn.net/Articles/69419/
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
While it is useful for new drivers to use devm_platform_ioremap_resource,
this script is currently used to spam maintainers, often updating very
old drivers. The net benefit is the removal of 2 lines of code in the
driver but the review load for the maintainers is huge. As of now, more
that 560 patches have been sent, some of them obviously broken, as in:
https://lore.kernel.org/lkml/9bbcce19c777583815c92ce3c2ff2586@www.loen.fr/
Remove the script to reduce the spam.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here is the big driver core update for 5.4-rc1.
There was a bit of a churn in here, with a number of core and OF
platform patches being added to the tree, and then after much discussion
and review and a day-long in-person meeting, they were decided to be
reverted and a new set of patches is currently being reviewed on the
mailing list.
Other than that churn, there are two "persistent" branches in here that
other trees will be pulling in as well during the merge window. One
branch to add support for drivers to have the driver core automatically
add sysfs attribute files when a driver is bound to a device so that the
driver doesn't have to manually do it (and then clean it up, as it
always gets it wrong).
There's another branch in here for generic lookup helpers for the driver
core that lots of busses are starting to use. That's the majority of
the non-driver-core changes in this patch series.
There's also some on-going debugfs file creation cleanup that has been
slowly happening over the past few releases, with the goal to hopefully
get that done sometime next year.
All of these have been in linux-next for a while now with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg Kroah-Hartman:
"Here is the big driver core update for 5.4-rc1.
There was a bit of a churn in here, with a number of core and OF
platform patches being added to the tree, and then after much
discussion and review and a day-long in-person meeting, they were
decided to be reverted and a new set of patches is currently being
reviewed on the mailing list.
Other than that churn, there are two "persistent" branches in here
that other trees will be pulling in as well during the merge window.
One branch to add support for drivers to have the driver core
automatically add sysfs attribute files when a driver is bound to a
device so that the driver doesn't have to manually do it (and then
clean it up, as it always gets it wrong).
There's another branch in here for generic lookup helpers for the
driver core that lots of busses are starting to use. That's the
majority of the non-driver-core changes in this patch series.
There's also some on-going debugfs file creation cleanup that has been
slowly happening over the past few releases, with the goal to
hopefully get that done sometime next year.
All of these have been in linux-next for a while now with no reported
issues"
[ Note that the above-mentioned generic lookup helpers branch was
already brought in by the LED merge (commit 4feaab05dc) that had
shared it.
Also note that that common branch introduced an i2c bug due to a bad
conversion, which got fixed here. - Linus ]
* tag 'driver-core-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (49 commits)
coccinelle: platform_get_irq: Fix parse error
driver-core: add include guard to linux/container.h
sysfs: add BIN_ATTR_WO() macro
driver core: platform: Export platform_get_irq_optional()
hwmon: pwm-fan: Use platform_get_irq_optional()
driver core: platform: Introduce platform_get_irq_optional()
Revert "driver core: Add support for linking devices during device addition"
Revert "driver core: Add edit_links() callback for drivers"
Revert "of/platform: Add functional dependency link from DT bindings"
Revert "driver core: Add sync_state driver/bus callback"
Revert "of/platform: Pause/resume sync state during init and of_platform_populate()"
Revert "of/platform: Create device links for all child-supplier depencencies"
Revert "of/platform: Don't create device links for default busses"
Revert "of/platform: Fix fn definitons for of_link_is_valid() and of_link_property()"
Revert "of/platform: Fix device_links_supplier_sync_state_resume() warning"
Revert "of/platform: Disable generic device linking code for PowerPC"
devcoredump: fix typo in comment
devcoredump: use memory_read_from_buffer
of/platform: Disable generic device linking code for PowerPC
device.h: Fix warnings for mismatched parameter names in comments
...
Add the missing GPLv2 SPDX license identifier.
It appears this single file was missing from 7f904d7e1f ("treewide:
Replace GPLv2 boilerplate/reference with SPDX - rule 505"), which
addressed all other files in scripts/coccinelle. Hence I added
GPL-2.0-only consitently with the mentioned patch.
Cc: linux-spdx@vger.kernel.org
Cc: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a coccinelle script to check for the usage of dev_err() after a call
to platform_get_irq{,_byname}() as it's redundant now that the function
already prints an error when it fails.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Markus Elfring <Markus.Elfring@web.de>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730053845.126834-4-swboyd@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use recently introduced devm_platform_ioremap_resource
helper which wraps platform_get_resource() and
devm_ioremap_resource() together. This helps produce much
cleaner code and remove local `struct resource` declaration.
Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
- the first one converts stream_open.cocci to treat all functions that
start with wait_.* as blocking. Previously it was only wait_event_.*
functions that were considered as blocking, but this was falsely
reporting several deadlock cases as only warning. The patch was
picked by linux-kbuild and entered mainline as 0c4ab18fc3.
It is thus omitted from hereby pull-request.
- the second one teaches stream_open.cocci to consider files as being
stream-like even if they use noop_llseek. I posted this patch for
review 3 weeks ago[1], but got neither feedback nor complaints.
[1] https://lore.kernel.org/lkml/20190623072838.31234-2-kirr@nexedi.com/
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Merge tag 'stream_open-5.3' of https://lab.nexedi.com/kirr/linux
Pull stream_open() updates from Kirill Smelkov:
"This time on stream_open front it is only two small changes:
- the first one converts stream_open.cocci to treat all functions
that start with wait_.* as blocking. Previously it was only
wait_event_.* functions that were considered as blocking, but this
was falsely reporting several deadlock cases as only warning.
This was picked by linux-kbuild and entered mainline as commit
0c4ab18fc3 ("coccinelle: api/stream_open: treat all wait_.*()
calls as blocking"), and already merged earlier.
- the second one teaches stream_open.cocci to consider files as being
stream-like even if they use noop_llseek. It results in two more
drivers being converted to stream_open() (mousedev.c and
hid-sensor-custom.c)"
* tag 'stream_open-5.3' of https://lab.nexedi.com/kirr/linux:
*: convert stream-like files -> stream_open, even if they use noop_llseek
This patch continues 10dce8af34 (fs: stream_open - opener for
stream-like files so that read and write can run simultaneously without
deadlock) and c5bf68fe0c (*: convert stream-like files from
nonseekable_open -> stream_open) and teaches steam_open.cocci to
consider files as being stream-like not only if they have
.llseek=no_llseek, but also if they have .llseek=noop_llseek.
This is safe to do: the comment about noop_llseek says
This is an implementation of ->llseek useable for the rare special case when
userspace expects the seek to succeed but the (device) file is actually not
able to perform the seek. In this case you use noop_llseek() instead of
falling back to the default implementation of ->llseek.
and in general noop_llseek was massively added to drivers in 6038f373a3
(llseek: automatically add .llseek fop) when changing default for NULL .llseek
from NOP to no_llseek with the idea to avoid breaking compatibility, if
maybe some user-space program was using lseek on a device without caring
about the result, but caring if it was an error or not.
Amended semantic patch produces two changes when applied tree-wide:
drivers/hid/hid-sensor-custom.c:690:8-24: WARNING: hid_sensor_custom_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
drivers/input/mousedev.c:564:1-17: ERROR: mousedev_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Jan Blunck <jblunck@suse.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
- remove headers_{install,check}_all targets
- remove unreasonable 'depends on !UML' from CONFIG_SAMPLES
- re-implement 'make headers_install' more cleanly
- add new header-test-y syntax to compile-test headers
- compile-test exported headers to ensure they are compilable in
user-space
- compile-test headers under include/ to ensure they are self-contained
- remove -Waggregate-return, -Wno-uninitialized, -Wno-unused-value flags
- add -Werror=unknown-warning-option for Clang
- add 128-bit built-in types support to genksyms
- fix missed rebuild of modules.builtin
- propagate 'No space left on device' error in fixdep to Make
- allow Clang to use its integrated assembler
- improve some coccinelle scripts
- add a new flag KBUILD_ABS_SRCTREE to request Kbuild to use absolute
path for $(srctree).
- do not ignore errors when compression utility is missing
- misc cleanups
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Merge tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- remove headers_{install,check}_all targets
- remove unreasonable 'depends on !UML' from CONFIG_SAMPLES
- re-implement 'make headers_install' more cleanly
- add new header-test-y syntax to compile-test headers
- compile-test exported headers to ensure they are compilable in
user-space
- compile-test headers under include/ to ensure they are self-contained
- remove -Waggregate-return, -Wno-uninitialized, -Wno-unused-value
flags
- add -Werror=unknown-warning-option for Clang
- add 128-bit built-in types support to genksyms
- fix missed rebuild of modules.builtin
- propagate 'No space left on device' error in fixdep to Make
- allow Clang to use its integrated assembler
- improve some coccinelle scripts
- add a new flag KBUILD_ABS_SRCTREE to request Kbuild to use absolute
path for $(srctree).
- do not ignore errors when compression utility is missing
- misc cleanups
* tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (49 commits)
kbuild: use -- separater intead of $(filter-out ...) for cc-cross-prefix
kbuild: Inform user to pass ARCH= for make mrproper
kbuild: fix compression errors getting ignored
kbuild: add a flag to force absolute path for srctree
kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctree
kbuild: remove src and obj from the top Makefile
scripts/tags.sh: remove unused environment variables from comments
scripts/tags.sh: drop SUBARCH support for ARM
kbuild: compile-test kernel headers to ensure they are self-contained
kheaders: include only headers into kheaders_data.tar.xz
kheaders: remove meaningless -R option of 'ls'
kbuild: support header-test-pattern-y
kbuild: do not create wrappers for header-test-y
kbuild: compile-test exported headers to ensure they are self-contained
init/Kconfig: add CONFIG_CC_CAN_LINK
kallsyms: exclude kasan local symbols on s390
kbuild: add more hints about SUBDIRS replacement
coccinelle: api/stream_open: treat all wait_.*() calls as blocking
coccinelle: put_device: Add a cast to an expression for an assignment
coccinelle: put_device: Adjust a message construction
...
Previously steam_open.cocci was treating only wait_event_.* - e.g.
wait_event_interruptible - as a blocking operation. However e.g.
wait_for_completion_interruptible is also blocking, and so from this
point of view it would be more logical to treat all wait_.* as a
blocking point.
The logic of this change actually came up for real when
drivers/pci/switch/switchtec.c changed from using
wait_event_interruptible to wait_for_completion_interruptible:
https://lore.kernel.org/linux-pci/20190413170056.GA11293@deco.navytux.spb.ru/https://lore.kernel.org/linux-pci/20190415145456.GA15280@deco.navytux.spb.ru/https://lore.kernel.org/linux-pci/20190415154102.GB17661@deco.navytux.spb.ru/
For a driver that uses nonseekable_open with read/write having stream
semantic and read also calling e.g. wait_for_completion_interruptible,
running stream_open.cocci before this patch would produce:
WARNING: <driver>_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
while after this patch it will report:
ERROR: <driver>_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Based on 1 normalized pattern(s):
gplv2
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 58 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081207.556988620@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Based on 1 normalized pattern(s):
gpl v2
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 19 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141333.108140152@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 9c225f2655 ("vfs: atomic f_pos accesses as per POSIX") added
locking for file.f_pos access and in particular made concurrent read and
write not possible - now both those functions take f_pos lock for the
whole run, and so if e.g. a read is blocked waiting for data, write will
deadlock waiting for that read to complete.
This caused regression for stream-like files where previously read and
write could run simultaneously, but after that patch could not do so
anymore. See e.g. commit 581d21a2d0 ("xenbus: fix deadlock on writes
to /proc/xen/xenbus") which fixes such regression for particular case of
/proc/xen/xenbus.
The patch that added f_pos lock in 2014 did so to guarantee POSIX thread
safety for read/write/lseek and added the locking to file descriptors of
all regular files. In 2014 that thread-safety problem was not new as it
was already discussed earlier in 2006.
However even though 2006'th version of Linus's patch was adding f_pos
locking "only for files that are marked seekable with FMODE_LSEEK (thus
avoiding the stream-like objects like pipes and sockets)", the 2014
version - the one that actually made it into the tree as 9c225f2655 -
is doing so irregardless of whether a file is seekable or not.
See
https://lore.kernel.org/lkml/53022DB1.4070805@gmail.com/https://lwn.net/Articles/180387https://lwn.net/Articles/180396
for historic context.
The reason that it did so is, probably, that there are many files that
are marked non-seekable, but e.g. their read implementation actually
depends on knowing current position to correctly handle the read. Some
examples:
kernel/power/user.c snapshot_read
fs/debugfs/file.c u32_array_read
fs/fuse/control.c fuse_conn_waiting_read + ...
drivers/hwmon/asus_atk0110.c atk_debugfs_ggrp_read
arch/s390/hypfs/inode.c hypfs_read_iter
...
Despite that, many nonseekable_open users implement read and write with
pure stream semantics - they don't depend on passed ppos at all. And for
those cases where read could wait for something inside, it creates a
situation similar to xenbus - the write could be never made to go until
read is done, and read is waiting for some, potentially external, event,
for potentially unbounded time -> deadlock.
Besides xenbus, there are 14 such places in the kernel that I've found
with semantic patch (see below):
drivers/xen/evtchn.c:667:8-24: ERROR: evtchn_fops: .read() can deadlock .write()
drivers/isdn/capi/capi.c:963:8-24: ERROR: capi_fops: .read() can deadlock .write()
drivers/input/evdev.c:527:1-17: ERROR: evdev_fops: .read() can deadlock .write()
drivers/char/pcmcia/cm4000_cs.c:1685:7-23: ERROR: cm4000_fops: .read() can deadlock .write()
net/rfkill/core.c:1146:8-24: ERROR: rfkill_fops: .read() can deadlock .write()
drivers/s390/char/fs3270.c:488:1-17: ERROR: fs3270_fops: .read() can deadlock .write()
drivers/usb/misc/ldusb.c:310:1-17: ERROR: ld_usb_fops: .read() can deadlock .write()
drivers/hid/uhid.c:635:1-17: ERROR: uhid_fops: .read() can deadlock .write()
net/batman-adv/icmp_socket.c:80:1-17: ERROR: batadv_fops: .read() can deadlock .write()
drivers/media/rc/lirc_dev.c:198:1-17: ERROR: lirc_fops: .read() can deadlock .write()
drivers/leds/uleds.c:77:1-17: ERROR: uleds_fops: .read() can deadlock .write()
drivers/input/misc/uinput.c:400:1-17: ERROR: uinput_fops: .read() can deadlock .write()
drivers/infiniband/core/user_mad.c:985:7-23: ERROR: umad_fops: .read() can deadlock .write()
drivers/gnss/core.c:45:1-17: ERROR: gnss_fops: .read() can deadlock .write()
In addition to the cases above another regression caused by f_pos
locking is that now FUSE filesystems that implement open with
FOPEN_NONSEEKABLE flag, can no longer implement bidirectional
stream-like files - for the same reason as above e.g. read can deadlock
write locking on file.f_pos in the kernel.
FUSE's FOPEN_NONSEEKABLE was added in 2008 in a7c1b990f7 ("fuse:
implement nonseekable open") to support OSSPD. OSSPD implements /dev/dsp
in userspace with FOPEN_NONSEEKABLE flag, with corresponding read and
write routines not depending on current position at all, and with both
read and write being potentially blocking operations:
See
https://github.com/libfuse/osspdhttps://lwn.net/Articles/308445https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1406https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1438-L1477https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1479-L1510
Corresponding libfuse example/test also describes FOPEN_NONSEEKABLE as
"somewhat pipe-like files ..." with read handler not using offset.
However that test implements only read without write and cannot exercise
the deadlock scenario:
https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L124-L131https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L146-L163https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L209-L216
I've actually hit the read vs write deadlock for real while implementing
my FUSE filesystem where there is /head/watch file, for which open
creates separate bidirectional socket-like stream in between filesystem
and its user with both read and write being later performed
simultaneously. And there it is semantically not easy to split the
stream into two separate read-only and write-only channels:
https://lab.nexedi.com/kirr/wendelin.core/blob/f13aa600/wcfs/wcfs.go#L88-169
Let's fix this regression. The plan is:
1. We can't change nonseekable_open to include &~FMODE_ATOMIC_POS -
doing so would break many in-kernel nonseekable_open users which
actually use ppos in read/write handlers.
2. Add stream_open() to kernel to open stream-like non-seekable file
descriptors. Read and write on such file descriptors would never use
nor change ppos. And with that property on stream-like files read and
write will be running without taking f_pos lock - i.e. read and write
could be running simultaneously.
3. With semantic patch search and convert to stream_open all in-kernel
nonseekable_open users for which read and write actually do not
depend on ppos and where there is no other methods in file_operations
which assume @offset access.
4. Add FOPEN_STREAM to fs/fuse/ and open in-kernel file-descriptors via
steam_open if that bit is present in filesystem open reply.
It was tempting to change fs/fuse/ open handler to use stream_open
instead of nonseekable_open on just FOPEN_NONSEEKABLE flags, but
grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE,
and in particular GVFS which actually uses offset in its read and
write handlers
https://codesearch.debian.net/search?q=-%3Enonseekable+%3Dhttps://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1080https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1247-1346https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1399-1481
so if we would do such a change it will break a real user.
5. Add stream_open and FOPEN_STREAM handling to stable kernels starting
from v3.14+ (the kernel where 9c225f2655 first appeared).
This will allow to patch OSSPD and other FUSE filesystems that
provide stream-like files to return FOPEN_STREAM | FOPEN_NONSEEKABLE
in their open handler and this way avoid the deadlock on all kernel
versions. This should work because fs/fuse/ ignores unknown open
flags returned from a filesystem and so passing FOPEN_STREAM to a
kernel that is not aware of this flag cannot hurt. In turn the kernel
that is not aware of FOPEN_STREAM will be < v3.14 where just
FOPEN_NONSEEKABLE is sufficient to implement streams without read vs
write deadlock.
This patch adds stream_open, converts /proc/xen/xenbus to it and adds
semantic patch to automatically locate in-kernel places that are either
required to be converted due to read vs write deadlock, or that are just
safe to be converted because read and write do not use ppos and there
are no other funky methods in file_operations.
Regarding semantic patch I've verified each generated change manually -
that it is correct to convert - and each other nonseekable_open instance
left - that it is either not correct to convert there, or that it is not
converted due to current stream_open.cocci limitations.
The script also does not convert files that should be valid to convert,
but that currently have .llseek = noop_llseek or generic_file_llseek for
unknown reason despite file being opened with nonseekable_open (e.g.
drivers/input/mousedev.c)
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yongzhi Pan <panyongzhi@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Nikolaus Rath <Nikolaus@rath.org>
Cc: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dma_zalloc_coherent() is no longer needed as it has no users because
dma_alloc_coherent() already zeroes out memory for us.
The Coccinelle grammar rule that used to check for dma_alloc_coherent()
+ memset() is modified so that it just tells the user that the memset is
not needed anymore.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The coccinelle script was used to rename some (deprecated) functions
which no longer exist now.
Signed-off-by: Fernando Ramos <greenfoo@gluegarage.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20181115221634.22715-9-greenfoo@gluegarage.com
Because pci_alloc_consistent has been deprecated. We prefer to use
dma_alloc_coherent directly. Therefore, we should remove pci_alloc_consistent
to increase the confidence.
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Acked-by: Himanshu Jha <himanshujha199640@gmail.com>
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
atomic_as_refcounter.cocci script allows detecting
cases when refcount_t type and API should be used
instead of atomic_t.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Backmerge tag 'v4.16-rc7' into drm-next
Linux 4.16-rc7
This was requested by Daniel, and things were getting
a bit hard to reconcile, most of the conflicts were
trivial though.
This patch remove the compatibility aliases
drm_property_{reference/unreference}_blob of
drm_property_blob_{get/put} since all callers have been converted to the
prefered _{get/put}.
Remove the helpers from the semantic patch drm-get-put-cocci.
Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180320133749.GA11695@haneen-VirtualBox
This patch remove the compatibility aliases
drm_mode_object_{reference/unreference} of drm_mode_object_{get/put}
since all callers have been converted to the prefered _{get/put}.
Remove the helpers from the semantic patch drm-get-put-cocci.
Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180319055820.GA17502@haneen-VirtualBox
The kmemdup line in the non-patch case was left over from the added kmemdup
line in the patch case.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Rename kzalloc-simple to zalloc-simple since now the rule is not
specific to kzalloc function only, but also to many other zero memory
allocating functions specified in the rule.
Suggested-by: SF Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Linus Torvalds