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A timer sigqueue may find itself already pending when it is tried to
be enqueued. This situation can happen if the timer sigqueue is enqueued
but then the timer is reset afterwards and fires before the pending
signal managed to be delivered.
However when such a double enqueue occurs while the corresponding signal
is ignored, the sigqueue is expected to be found either on the dedicated
ignored list if the timer was periodic or dropped if the timer was
one-shot. In any case it is not supposed to be queued on the real signal
queue.
An assertion verifies the latter expectation on top of the return value
of prepare_signal(), assuming "false" means that the signal is being
ignored. But prepare_signal() may also fail if the target is exiting as
the last task of its group. In this case the double enqueue observes the
sigqueue queued, as in such a situation:
TASK A (same group as B) TASK B (same group as A)
------------------------ ------------------------
// timer event
// queue signal to TASK B
posix_timer_queue_signal()
// reset timer through syscall
do_timer_settime()
// exit, leaving task B alone
do_exit()
do_exit()
synchronize_group_exit()
signal->flags = SIGNAL_GROUP_EXIT
// ========> <IRQ> timer event
posix_timer_queue_signal()
// return false due to SIGNAL_GROUP_EXIT
if (!prepare_signal())
WARN_ON_ONCE(!list_empty(&q->list))
And this spuriously triggers this warning:
WARNING: CPU: 0 PID: 5854 at kernel/signal.c:2008 posixtimer_send_sigqueue
CPU: 0 UID: 0 PID: 5854 Comm: syz-executor139 Not tainted 6.12.0-rc6-next-20241108-syzkaller #0
RIP: 0010:posixtimer_send_sigqueue+0x9da/0xbc0 kernel/signal.c:2008
Call Trace:
<IRQ>
alarm_handle_timer
alarmtimer_fired
__run_hrtimer
__hrtimer_run_queues
hrtimer_interrupt
local_apic_timer_interrupt
__sysvec_apic_timer_interrupt
instr_sysvec_apic_timer_interrupt
sysvec_apic_timer_interrupt
</IRQ>
Fortunately the recovery code in that case already does the right thing:
just exit from posixtimer_send_sigqueue() and wait for __exit_signal()
to flush the pending signal. Just make sure to warn only the case when
the sigqueue is queued and the signal is really ignored.
Fixes: df7a996b4dab ("signal: Queue ignored posixtimers on ignore list")
Reported-by: syzbot+852e935b899bde73626e@syzkaller.appspotmail.com
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: syzbot+852e935b899bde73626e@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/20241116234823.28497-1-frederic@kernel.org
Closes: https://lore.kernel.org/all/673549c6.050a0220.1324f8.008c.GAE@google.com
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https://git.linaro.org/people/daniel.lezcano/linux into timers/core
Pull clocksource/event updates from Daniel Lezcano:
- Remove unused dw_apb_clockevent_[pause|resume|stop] functions as
they are unused since 2021 (David Alan Gilbert)
- Make the sp804 driver user selectable as they may be unused on some
platforms (Mark Brown)
- Don't fail if the ti-dm does not describe an interrupt in the DT as
this could be a normal situation if the PWM is used (Judith Mendez)
- Always use cluster 0 counter as a clocksource on a multi-cluster
system to prevent problems related to the time shifting between
clusters if multiple per cluster clocksource is used (Paul Burton)
- Move the RaLink system tick counter from the arch directory to the
clocksource directory (Sergio Paracuellos)
- Convert the owl-timer bindings into yaml schema (Ivaylo Ivanov)
- Fix child node refcount handling on the TI DM by relying on the
__free annotation to automatically release the refcount on the node
(Javier Carrasco)
- Remove pointless cast in the GPX driver as PTR_ERR already does that
(Tang Bin)
- Use of_property_present() for non-boolean properties where it is
possible in the different drivers (Rob Herring)
Link: https://lore.kernel.org/lkml/8d402321-96f1-47f7-9347-a850350d60de@linaro.org
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non-boolean properties
The use of of_property_read_bool() for non-boolean properties is
deprecated in favor of of_property_present() when testing for property
presence.
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20241104190505.272805-2-robh@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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In the function gxp_timer_init, the 'int' type cast in front of the
PTR_ERR() macro is redundant, thus remove it.
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20241107074619.2714-1-tangbin@cmss.chinamobile.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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of_find_compatible_node() increments the node's refcount, and it must be
decremented again with a call to of_node_put() when the pointer is no
longer required to avoid leaking the resource.
Instead of adding the missing calls to of_node_put() in all execution
paths, use the cleanup attribute for 'arm_timer' by means of the
__free() macro, which automatically calls of_node_put() when the
variable goes out of scope.
Fixes: 25de4ce5ed02 ("clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20241031-timer-ti-dm-systimer-of_node_put-v3-1-063ee822b73a@gmail.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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Convert the Actions Semi Owl timer bindings to DT schema.
Changes during conversion:
- Add a description
- Add "clocks" as a required property, since the driver searches for it
- Correct the given example according to owl-s500.dtsi
Signed-off-by: Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20241103123513.2890107-1-ivo.ivanov.ivanov1@gmail.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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System Tick Counter is present on Ralink SoCs RT3352 and MT7620. This
driver has been in 'arch/mips/ralink' directory since the beggining of
Ralink architecture support. However, it can be moved into a more proper
place in 'drivers/clocksource'. Hence add it here adding also support for
compile test targets and reducing LOC in architecture code folder.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20241028203643.191268-2-sergio.paracuellos@gmail.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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In a multi-cluster MIPS system, there are multiple GICs - one in each
cluster - each of which has its independent counter. The counters in
each GIC are not synchronized in any way, so they can drift relative
to one another through the lifetime of the system. This is problematic
for a clock source which ought to be global.
Avoid problems by always accessing cluster 0's counter, using
cross-cluster register access. This adds overhead so it is applied only
on multi-cluster systems.
Signed-off-by: Paul Burton <paulburton@kernel.org>
Signed-off-by: Chao-ying Fu <cfu@wavecomp.com>
Signed-off-by: Dragan Mladjenovic <dragan.mladjenovic@syrmia.com>
Signed-off-by: Aleksandar Rikalo <arikalo@gmail.com>
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Tested-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20241019071037.145314-6-arikalo@gmail.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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Some timers may not have an interrupt routed to the A53 GIC, but the
timer PWM functionality can still be used by Linux Kernel. Therefore,
do not fail probe if interrupt is not found and ti,timer-pwm exists.
Signed-off-by: Judith Mendez <jm@ti.com>
Link: https://lore.kernel.org/r/20241011175203.1040568-1-jm@ti.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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The sp804 is currently only user selectable if COMPILE_TEST, this was
done by commit dfc82faad725 ("clocksource/drivers/sp804: Add
COMPILE_TEST to CONFIG_ARM_TIMER_SP804") in order to avoid it being
spuriously offered on platforms that won't have the hardware since it's
generally only seen on Arm based platforms. This config is overly
restrictive, while platforms that rely on the SP804 do select it in
their Kconfig there are others such as the Arm fast models which have a
SP804 available but currently unused by Linux. Relax the dependency to
allow it to be user selectable on arm and arm64 to avoid surprises and
in case someone comes up with a use for extra timer hardware.
Fixes: dfc82faad725 ("clocksource/drivers/sp804: Add COMPILE_TEST to CONFIG_ARM_TIMER_SP804")
Reported-by: Ross Burton <ross.burton@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241001-arm64-vexpress-sp804-v3-1-0a2d3f7883e4@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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dw_apb_clockevent_pause(), dw_apb_clockevent_resume() and
dw_apb_clockevent_stop() have been unused since 2021's
commit 1b79fc4f2bfd ("x86/apb_timer: Remove driver for deprecated
platform")
Remove them.
(Some of the other clockevent functions are still called by
dw_apb_timer_of.c so I guess it is still in use?)
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20241025203101.241709-1-linux@treblig.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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hrtimer_init_on_stack() is now unused. Delete it.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/510ce0d2944c4a382ea51e51d03dcfb73ba0f4f7.1730386209.git.namcao@linutronix.de
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hrtimer_setup() and hrtimer_setup_on_stack() take the callback function
pointer as argument and initialize the timer completely.
Replace the hrtimer_init*() variants and the open coded initialization of
hrtimer::function with the new setup mechanism.
Switch to use the new functions.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/2bae912336103405adcdab96b88d3ea0353b4228.1730386209.git.namcao@linutronix.de
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hrtimer_setup_on_stack() takes the callback function pointer as argument
and initializes the timer completely.
Replace hrtimer_init_on_stack() and the open coded initialization of
hrtimer::function with the new setup mechanism.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/f0d4ac32ec4050710a656cee8385fa4427be33aa.1730386209.git.namcao@linutronix.de
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hrtimer_setup_on_stack() takes the callback function pointer as argument
and initializes the timer completely.
Replace hrtimer_init_on_stack() and the open coded initialization of
hrtimer::function with the new setup mechanism.
The conversion was done with Coccinelle.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/17f9421fed6061df4ad26a4cc91873d2c078cb0f.1730386209.git.namcao@linutronix.de
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hrtimer_init_sleeper_on_stack() is now unused. Delete it.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/52549846635c0b3a2abf82101f539efdabcd9778.1730386209.git.namcao@linutronix.de
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hrtimer_setup_sleeper_on_stack() replaces hrtimer_init_sleeper_on_stack()
to keep the naming convention consistent.
Convert the usage site over to it.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/fc91182375df81120a88dbe0263267e24d1bf19e.1730386209.git.namcao@linutronix.de
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hrtimer_setup_sleeper_on_stack() replaces hrtimer_init_sleeper_on_stack()
to keep the naming convention consistent.
Convert the usage sites over to it. The conversion was done with
Coccinelle.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/299c07f0f96af8ab3a7631b47b6ca22b06b20577.1730386209.git.namcao@linutronix.de
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hrtimer_setup_sleeper_on_stack() replaces hrtimer_init_sleeper_on_stack()
to keep the naming convention consistent.
Convert the usage site over to it. The conversion was done with Coccinelle.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/c4b40b8fef250b6a325e1b8bd6057005fb3cb660.1730386209.git.namcao@linutronix.de
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hrtimer_setup_sleeper_on_stack() replaces hrtimer_init_sleeper_on_stack()
to keep the naming convention consistent.
Convert the usage site over to it. The conversion was done with Coccinelle.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/d92116a17313dee283ebc959869bea80fbf94cdb.1730386209.git.namcao@linutronix.de
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hrtimer_setup_sleeper_on_stack() replaces hrtimer_init_sleeper_on_stack()
to keep the naming convention consistent.
Convert the usage site over to it. The conversion was done with Coccinelle.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/5f10c259fa43ba2fe774de5b2cedc22f5e9cfd2d.1730386209.git.namcao@linutronix.de
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Some users of hrtimer need to change the callback function after the
initial setup. They write to hrtimer::function directly.
That's not safe under all circumstances as the write is lockless and a
concurrent timer expiry might end up using the wrong function pointer.
Introduce hrtimer_update_function(), which also performs runtime checks
whether it is safe to modify the callback.
This allows to make hrtimer::function private once all users are converted.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20a937b0ae09ad54b5b6d86eabead7c570f1b72e.1730386209.git.namcao@linutronix.de
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The hrtimer_init*() API is replaced by hrtimer_setup*() variants to
initialize the timer including the callback function at once.
hrtimer_init_sleeper_on_stack() does not need user to setup the callback
function separately, so a new variant would not be strictly necessary.
Nonetheless, to keep the naming convention consistent, introduce
hrtimer_setup_sleeper_on_stack(). hrtimer_init_on_stack() will be removed
once all users are converted.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/7b5e18e6dd0ace9eaa211201528cb9dc23752454.1730386209.git.namcao@linutronix.de
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To initialize hrtimer on stack, hrtimer_init_on_stack() needs to be called
and also hrtimer::function must be set. This is error-prone and awkward to
use.
Introduce hrtimer_setup_on_stack() which does both of these things, so that
users of hrtimer can be simplified.
The new setup function also has a sanity check for the provided function
pointer. If NULL, a warning is emitted and a dummy callback installed.
hrtimer_init_on_stack() will be removed as soon as all of its users have
been converted to the new function.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/4b05e2ab3a82c517adf67fabc0f0cd8fe118b97c.1730386209.git.namcao@linutronix.de
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To initialize hrtimer, hrtimer_init() needs to be called and also
hrtimer::function must be set. This is error-prone and awkward to use.
Introduce hrtimer_setup() which does both of these things, so that users of
hrtimer can be simplified.
The new setup function also has a sanity check for the provided function
pointer. If NULL, a warning is emitted and a dummy callback installed.
hrtimer_init() will be removed as soon as all of its users have been
converted to the new function.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/5057c1ddbfd4b92033cd93d37fe38e6b069d5ba6.1730386209.git.namcao@linutronix.de
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The IORING_OP_TIMEOUT command uses hrtimer underneath. The timer's callback
function is setup in io_timeout(), and then the callback function is setup
again when the timer is rearmed.
Since the callback function is the same for both cases, the latter setup is
redundant, therefore remove it.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk:
Link: https://lore.kernel.org/all/07b28dfd5691478a2d250f379c8b90dd37f9bb9a.1730386209.git.namcao@linutronix.de
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rt2x00usb_probe() executes a hrtimer_init() for txstatus_timer. Afterwards,
rt2x00lib_probe_dev() is called which also initializes this txstatus_timer
with the same settings.
Remove the redundant hrtimer_init() call in rt2x00usb_probe().
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/all/66116057f788e18a6603d50a554417eee459e02c.1730386209.git.namcao@linutronix.de
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The hrtimer is initialized in the KVM_XEN_VCPU_SET_ATTR ioctl. That caused
problem in the past, because the hrtimer can be initialized multiple times,
which was fixed by commit af735db31285 ("KVM: x86/xen: Initialize Xen timer
only once"). This commit avoids initializing the timer multiple times by
checking the field 'function' of struct hrtimer to determine if it has
already been initialized.
This is not required and in the way to make the function field private.
Move the hrtimer initialization into kvm_xen_init_vcpu() so that it will
only be initialized once.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/all/9c33c7224d97d08f4fa30d3cc8687981c1d3e953.1730386209.git.namcao@linutronix.de
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When a request is created, the hrtimer is not initialized and only its
'function' field is set to NULL. The hrtimer is only initialized when the
request is enqueued. The point of setting 'function' to NULL is that, it
can be used to check whether hrtimer_try_to_cancel() should be called while
retiring the request.
This "trick" is unnecessary, because hrtimer_try_to_cancel() already does
its own check whether the timer is armed. If the timer is not armed,
hrtimer_try_to_cancel() returns 0.
Fully initialize the timer when the request is created, which allows to
make the hrtimer::function field private once all users of hrtimer_init()
are converted to hrtimer_setup(), which requires a valid callback function
to be set.
Because hrtimer_try_to_cancel() returns 0 if the timer is not armed, the
logic to check whether to call i915_request_put() remains equivalent.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/50f865045aa672a9730343ad131543da332b1d8d.1730386209.git.namcao@linutronix.de
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hrtimer_init*_on_stack() is not covered by tracing when
CONFIG_DEBUG_OBJECTS_TIMERS=y.
Rework the functions similar to hrtimer_init() and hrtimer_init_sleeper()
so that the hrtimer_init() tracepoint is unconditionally available.
The rework makes hrtimer_init_sleeper() unused. Delete it.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/74528e8abf2bb96e8bee85ffacbf14e15cf89f0d.1730386209.git.namcao@linutronix.de
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Now that the SIG_IGN problem is solved in the core code, the alarmtimer
callbacks do not require a return value anymore.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241105064214.318837272@linutronix.de
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Now that ignored posix timer signals are requeued and the timers are
rearmed on signal delivery the workaround to keep such timers alive and
self rearm them is not longer required.
Remove the unused alarm timer parts.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064214.252443020@linutronix.de
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Now that ignored posix timer signals are requeued and the timers are
rearmed on signal delivery the workaround to keep such timers alive and
self rearm them is not longer required.
Remove the relevant hacks and the not longer required return values from
the related functions. The alarm timer workarounds will be cleaned up in a
separate step.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064214.187239060@linutronix.de
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Queue posixtimers which have their signal ignored on the ignored list:
1) When the timer fires and the signal has SIG_IGN set
2) When SIG_IGN is installed via sigaction() and a timer signal
is already queued
This only happens when the signal is for a valid timer, which delivered the
signal in periodic mode. One-shot timer signals are correctly dropped.
Due to the lock order constraints (sighand::siglock nests inside
timer::lock) the signal code cannot access any of the timer fields which
are relevant to make this decision, e.g. timer::it_status.
This is addressed by establishing a protection scheme which requires to
lock both locks on the timer side for modifying decision fields in the
timer struct and therefore makes it possible for the signal delivery to
evaluate with only sighand:siglock being held:
1) Move the NULLification of timer->it_signal into the sighand::siglock
protected section of timer_delete() and check timer::it_signal in the
code path which determines whether the signal is dropped or queued on
the ignore list.
This ensures that a deleted timer cannot be moved onto the ignore
list, which would prevent it from being freed on exit() as it is not
longer in the process' posix timer list.
If the timer got moved to the ignored list before deletion then it is
removed from the ignored list under sighand lock in timer_delete().
2) Provide a new timer::it_sig_periodic flag, which gets set in the
signal queue path with both timer and sighand locks held if the timer
is actually in periodic mode at expiry time.
The ignore list code checks this flag under sighand::siglock and drops
the signal when it is not set.
If it is set, then the signal is moved to the ignored list independent
of the actual state of the timer.
When the signal is un-ignored later then the signal is moved back to
the signal queue. On signal delivery the posix timer side decides
about dropping the signal if the timer was re-armed, dis-armed or
deleted based on the signal sequence counter check.
If the thread/process exits then not yet delivered signals are
discarded which means the reference of the timer containing the
sigqueue is dropped and frees the timer.
This is way cheaper than requiring all code paths to lock
sighand::siglock of the target thread/process on any modification of
timer::it_status or going all the way and removing pending signals
from the signal queues on every rearm, disarm or delete operation.
So the protection scheme here is that on the timer side both timer::lock
and sighand::siglock have to be held for modifying
timer::it_signal
timer::it_sig_periodic
which means that on the signal side holding sighand::siglock is enough to
evaluate these fields.
In posixtimer_deliver_signal() holding timer::lock is sufficient to do the
sequence validation against timer::it_signal_seq because a concurrent
expiry is waiting on timer::lock to be released.
This completes the SIG_IGN handling and such timers are not longer self
rearmed which avoids pointless wakeups.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064214.120756416@linutronix.de
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When a real handler (including SIG_DFL) is installed for a signal, which
had previously SIG_IGN set, then the list of ignored posix timers has to be
checked for timers which are affected by this change.
Add a list walk function which checks for the matching signal number and if
found requeues the timers signal, so the timer is rearmed on signal
delivery.
Rearming the timer right away is not possible because that requires to drop
sighand lock.
No functional change as the counter part which queues the timers on the
ignored list is still missing.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064214.054091076@linutronix.de
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To handle posix timer signals on sigaction(SIG_IGN) properly, the timers
will be queued on a separate ignored list.
Add the necessary cleanup code for timer_delete() and exit_itimers().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.987530588@linutronix.de
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To prepare for handling posix timer signals on sigaction(SIG_IGN) properly,
add a list to task::signal.
This list will be used to queue posix timers so their signal can be
requeued when SIG_IGN is lifted later.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.920101900@linutronix.de
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The posix timer signal handling uses siginfo::si_sys_private for handling
the sequence counter check. That indirection is not longer required and the
sequence count value at signal queueing time can be stored in struct
k_itimer itself.
This removes the requirement of treating siginfo::si_sys_private special as
it's now always zero as the kernel does not touch it anymore.
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/all/20241105064213.852619866@linutronix.de
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Remove the leftovers of sigqueue preallocation as it's not longer used.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.786506636@linutronix.de
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To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
Now that the prerequisites are in place, embed the sigqueue into struct
k_itimer and fixup the relevant usage sites.
Aside of preparing for proper SIG_IGN handling, this spares an extra
allocation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.719695194@linutronix.de
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In preparation for handling ignored posix timer signals correctly and
embedding the sigqueue struct into struct k_itimer, hand down a pointer to
the sigqueue struct into posix_timer_deliver_signal() instead of just
having a boolean flag.
No functional change.
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/all/20241105064213.652658158@linutronix.de
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To handle posix timers which have their signal ignored via SIG_IGN properly
it is required to requeue a ignored signal for delivery when SIG_IGN is
lifted so the timer gets rearmed.
Split the required code out of send_sigqueue() so it can be reused in
context of sigaction().
While at it rename send_sigqueue() to posixtimer_send_sigqueue() so its
clear what this is about.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.586453412@linutronix.de
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instead of re-evaluating the signal delivery mode everywhere.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.519086500@linutronix.de
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To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
Provide a new function to initialize the embedded sigqueue to prepare for
that.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.450427515@linutronix.de
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To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
Reorganize __sigqueue_alloc() so the ucounts retrieval and the
initialization can be used independently.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.371410037@linutronix.de
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To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
To make that work correctly it needs reference counting so that timer
deletion does not free the timer prematuraly when there is a signal queued
or delivered concurrently.
Add a rcuref to the posix timer part.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.304756440@linutronix.de
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POSIX CPU timer nanosleep creates a k_itimer on stack and uses the sigq
pointer to detect the nanosleep case in the expiry function.
Prepare for embedding sigqueue into struct k_itimer by using a dedicated
flag for nanosleep.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.238550394@linutronix.de
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The firing flag of a posix CPU timer is tristate:
0: when the timer is not about to deliver a signal
1: when the timer has expired, but the signal has not been delivered yet
-1: when the timer was queued for signal delivery and a rearm operation
raced against it and supressed the signal delivery.
This is a pointless exercise as this can be simply expressed with a
boolean. Only if set, the signal is delivered. This makes delete and rearm
consistent with the rest of the posix timers.
Convert firing to bool and fixup the usage sites accordingly and add
comments why the timer cannot be dequeued right away.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241105064213.172848618@linutronix.de
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The handling of the timer overrun in the signal code is inconsistent as it
takes previous overruns into account. This is just wrong as after the
reprogramming of a timer the overrun count starts over from a clean state,
i.e. 0.
Don't touch info::si_overrun in send_sigqueue() and only store the overrun
value at signal delivery time, which is computed from the timer itself
relative to the expiry time.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.106738193@linutronix.de
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Signals of timers which are reprogammed, disarmed or deleted can deliver
signals related to the past. The POSIX spec is blury about this:
- "The effect of disarming or resetting a timer with pending expiration
notifications is unspecified."
- "The disposition of pending signals for the deleted timer is
unspecified."
In both cases it is reasonable to expect that pending signals are
discarded. Especially in the reprogramming case it does not make sense to
account for previous overruns or to deliver a signal for a timer which has
been disarmed. This makes the behaviour consistent and understandable.
Remove the si_sys_private check from the signal delivery code and invoke
posix_timer_deliver_signal() unconditionally for posix timer related
signals.
Change posix_timer_deliver_signal() so it controls the actual signal
delivery via the return value. It now instructs the signal code to drop the
signal when:
1) The timer does not longer exist in the hash table
2) The timer signal_seq value is not the same as the si_sys_private value
which was set when the signal was queued.
This is also a preparatory change to embed the sigqueue into the k_itimer
structure, which in turn allows to remove the si_sys_private magic.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241105064213.040348644@linutronix.de
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