In the IRQ handler, the GPIO's state is read to verify the direction of
the edge that triggered the interruption before generating the PPS event.
If a pulse is too short, the GPIO line can reach back its original state
before this verification and the PPS event is lost.
This check is needed when info->capture_clear is set because it needs
interruptions on both rising and falling edges. When info->capture_clear
is not set, interruption is triggered by one edge only so this check can
be omitted.
Add a warning if irq_handler is left without triggering any PPS event.
Bypass the edge's direction verification when info->capture_clear is not
set.
Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/20250108153012.514925-1-bastien.curutchet@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Sometimes one needs to be able not only to catch PPS signals but to
produce them also. For example, running a distributed simulation,
which requires computers' clock to be synchronized very tightly.
This patch adds PPS generators class in order to have a well-defined
interface for these devices.
Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/20241108073115.759039-2-giometti@enneenne.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On a board running ntpd and gpsd, I'm seeing a consistent use-after-free
in sys_exit() from gpsd when rebooting:
pps pps1: removed
------------[ cut here ]------------
kobject: '(null)' (00000000db4bec24): is not initialized, yet kobject_put() is being called.
WARNING: CPU: 2 PID: 440 at lib/kobject.c:734 kobject_put+0x120/0x150
CPU: 2 UID: 299 PID: 440 Comm: gpsd Not tainted 6.11.0-rc6-00308-gb31c44928842 #1
Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : kobject_put+0x120/0x150
lr : kobject_put+0x120/0x150
sp : ffffffc0803d3ae0
x29: ffffffc0803d3ae0 x28: ffffff8042dc9738 x27: 0000000000000001
x26: 0000000000000000 x25: ffffff8042dc9040 x24: ffffff8042dc9440
x23: ffffff80402a4620 x22: ffffff8042ef4bd0 x21: ffffff80405cb600
x20: 000000000008001b x19: ffffff8040b3b6e0 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 696e6920746f6e20
x14: 7369203a29343263 x13: 205d303434542020 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
kobject_put+0x120/0x150
cdev_put+0x20/0x3c
__fput+0x2c4/0x2d8
____fput+0x1c/0x38
task_work_run+0x70/0xfc
do_exit+0x2a0/0x924
do_group_exit+0x34/0x90
get_signal+0x7fc/0x8c0
do_signal+0x128/0x13b4
do_notify_resume+0xdc/0x160
el0_svc+0xd4/0xf8
el0t_64_sync_handler+0x140/0x14c
el0t_64_sync+0x190/0x194
---[ end trace 0000000000000000 ]---
...followed by more symptoms of corruption, with similar stacks:
refcount_t: underflow; use-after-free.
kernel BUG at lib/list_debug.c:62!
Kernel panic - not syncing: Oops - BUG: Fatal exception
This happens because pps_device_destruct() frees the pps_device with the
embedded cdev immediately after calling cdev_del(), but, as the comment
above cdev_del() notes, fops for previously opened cdevs are still
callable even after cdev_del() returns. I think this bug has always
been there: I can't explain why it suddenly started happening every time
I reboot this particular board.
In commit d953e0e837 ("pps: Fix a use-after free bug when
unregistering a source."), George Spelvin suggested removing the
embedded cdev. That seems like the simplest way to fix this, so I've
implemented his suggestion, using __register_chrdev() with pps_idr
becoming the source of truth for which minor corresponds to which
device.
But now that pps_idr defines userspace visibility instead of cdev_add(),
we need to be sure the pps->dev refcount can't reach zero while
userspace can still find it again. So, the idr_remove() call moves to
pps_unregister_cdev(), and pps_idr now holds a reference to pps->dev.
pps_core: source serial1 got cdev (251:1)
<...>
pps pps1: removed
pps_core: unregistering pps1
pps_core: deallocating pps1
Fixes: d953e0e837 ("pps: Fix a use-after free bug when unregistering a source.")
Cc: stable@vger.kernel.org
Signed-off-by: Calvin Owens <calvin@wbinvd.org>
Reviewed-by: Michal Schmidt <mschmidt@redhat.com>
Link: https://lore.kernel.org/r/a17975fd5ae99385791929e563f72564edbcf28f.1731383727.git.calvin@wbinvd.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The continual trickle of small conversion patches is grating on me, and
is really not helping. Just get rid of the 'remove_new' member
function, which is just an alias for the plain 'remove', and had a
comment to that effect:
/*
* .remove_new() is a relic from a prototype conversion of .remove().
* New drivers are supposed to implement .remove(). Once all drivers are
* converted to not use .remove_new any more, it will be dropped.
*/
This was just a tree-wide 'sed' script that replaced '.remove_new' with
'.remove', with some care taken to turn a subsequent tab into two tabs
to make things line up.
I did do some minimal manual whitespace adjustment for places that used
spaces to line things up.
Then I just removed the old (sic) .remove_new member function, and this
is the end result. No more unnecessary conversion noise.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
no_llseek had been defined to NULL two years ago, in commit 868941b144
("fs: remove no_llseek")
To quote that commit,
At -rc1 we'll need do a mechanical removal of no_llseek -
git grep -l -w no_llseek | grep -v porting.rst | while read i; do
sed -i '/\<no_llseek\>/d' $i
done
would do it.
Unfortunately, that hadn't been done. Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
.llseek = no_llseek,
so it's obviously safe.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull driver core updates from Greg KH:
"Here is the big set of driver core changes for 6.11-rc1.
Lots of stuff in here, with not a huge diffstat, but apis are evolving
which required lots of files to be touched. Highlights of the changes
in here are:
- platform remove callback api final fixups (Uwe took many releases
to get here, finally!)
- Rust bindings for basic firmware apis and initial driver-core
interactions.
It's not all that useful for a "write a whole driver in rust" type
of thing, but the firmware bindings do help out the phy rust
drivers, and the driver core bindings give a solid base on which
others can start their work.
There is still a long way to go here before we have a multitude of
rust drivers being added, but it's a great first step.
- driver core const api changes.
This reached across all bus types, and there are some fix-ups for
some not-common bus types that linux-next and 0-day testing shook
out.
This work is being done to help make the rust bindings more safe,
as well as the C code, moving toward the end-goal of allowing us to
put driver structures into read-only memory. We aren't there yet,
but are getting closer.
- minor devres cleanups and fixes found by code inspection
- arch_topology minor changes
- other minor driver core cleanups
All of these have been in linux-next for a very long time with no
reported problems"
* tag 'driver-core-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits)
ARM: sa1100: make match function take a const pointer
sysfs/cpu: Make crash_hotplug attribute world-readable
dio: Have dio_bus_match() callback take a const *
zorro: make match function take a const pointer
driver core: module: make module_[add|remove]_driver take a const *
driver core: make driver_find_device() take a const *
driver core: make driver_[create|remove]_file take a const *
firmware_loader: fix soundness issue in `request_internal`
firmware_loader: annotate doctests as `no_run`
devres: Correct code style for functions that return a pointer type
devres: Initialize an uninitialized struct member
devres: Fix memory leakage caused by driver API devm_free_percpu()
devres: Fix devm_krealloc() wasting memory
driver core: platform: Switch to use kmemdup_array()
driver core: have match() callback in struct bus_type take a const *
MAINTAINERS: add Rust device abstractions to DRIVER CORE
device: rust: improve safety comments
MAINTAINERS: add Danilo as FIRMWARE LOADER maintainer
MAINTAINERS: add Rust FW abstractions to FIRMWARE LOADER
firmware: rust: improve safety comments
...
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/f4b9402af72e5f285c8b0f068076a76418f653f5.1709886922.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Pull tty and serial driver updates from Greg KH:
"Here is the big set of tty and serial driver updates for 5.13-rc1.
Actually busy this release, with a number of cleanups happening:
- much needed core tty cleanups by Jiri Slaby
- removal of unused and orphaned old-style serial drivers. If anyone
shows up with this hardware, it is trivial to restore these but we
really do not think they are in use anymore.
- fixes and cleanups from Johan Hovold on a number of termios setting
corner cases that loads of drivers got wrong as well as removing
unneeded code due to tty core changes from long ago that were never
propagated out to the drivers
- loads of platform-specific serial port driver updates and fixes
- coding style cleanups and other small fixes and updates all over
the tty/serial tree.
All of these have been in linux-next for a while now with no reported
issues"
* tag 'tty-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (186 commits)
serial: extend compile-test coverage
serial: stm32: add FIFO threshold configuration
dt-bindings: serial: 8250: update TX FIFO trigger level
dt-bindings: serial: stm32: override FIFO threshold properties
dt-bindings: serial: add RX and TX FIFO properties
serial: xilinx_uartps: drop low-latency workaround
serial: vt8500: drop low-latency workaround
serial: timbuart: drop low-latency workaround
serial: sunsu: drop low-latency workaround
serial: sifive: drop low-latency workaround
serial: txx9: drop low-latency workaround
serial: sa1100: drop low-latency workaround
serial: rp2: drop low-latency workaround
serial: rda: drop low-latency workaround
serial: owl: drop low-latency workaround
serial: msm_serial: drop low-latency workaround
serial: mpc52xx_uart: drop low-latency workaround
serial: meson: drop low-latency workaround
serial: mcf: drop low-latency workaround
serial: lpc32xx_hs: drop low-latency workaround
...
