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I got some resource leak reports while doing fault injection test:
OF: ERROR: memory leak, expected refcount 1 instead of 100,
of_node_get()/of_node_put() unbalanced - destroy cset entry:
attach overlay node /i2c/pmic@64/regulators/buck1
unreferenced object 0xffff88810deea000 (size 512):
comm "490-i2c-rt5190a", pid 253, jiffies 4294859840 (age 5061.046s)
hex dump (first 32 bytes):
00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N..........
ff ff ff ff ff ff ff ff a0 1e 00 a1 ff ff ff ff ................
backtrace:
[<00000000d78541e2>] kmalloc_trace+0x21/0x110
[<00000000b343d153>] device_private_init+0x32/0xd0
[<00000000be1f0c70>] device_add+0xb2d/0x1030
[<00000000e3e6344d>] regulator_register+0xaf2/0x12a0
[<00000000e2f5e754>] devm_regulator_register+0x57/0xb0
[<000000008b898197>] rt5190a_probe+0x52a/0x861 [rt5190a_regulator]
unreferenced object 0xffff88810b617b80 (size 32):
comm "490-i2c-rt5190a", pid 253, jiffies 4294859904 (age 5060.983s)
hex dump (first 32 bytes):
72 65 67 75 6c 61 74 6f 72 2e 32 38 36 38 2d 53 regulator.2868-S
55 50 50 4c 59 00 ff ff 29 00 00 00 2b 00 00 00 UPPLY...)...+...
backtrace:
[<000000009da9280d>] __kmalloc_node_track_caller+0x44/0x1b0
[<0000000025c6a4e5>] kstrdup+0x3a/0x70
[<00000000790efb69>] create_regulator+0xc0/0x4e0
[<0000000005ed203a>] regulator_resolve_supply+0x2d4/0x440
[<0000000045796214>] regulator_register+0x10b3/0x12a0
[<00000000e2f5e754>] devm_regulator_register+0x57/0xb0
[<000000008b898197>] rt5190a_probe+0x52a/0x861 [rt5190a_regulator]
After calling regulator_resolve_supply(), the 'rdev->supply' is set
by set_supply(), after this set, in the error path, the resources
need be released, so call regulator_put() to avoid the leaks.
Fixes: aea6cb99703e ("regulator: resolve supply after creating regulator")
Fixes: 8a866d527ac0 ("regulator: core: Resolve supply name earlier to prevent double-init")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221202025111.496402-1-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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Due to the explicit 'noinline' GCC-7.3 is not able to optimize away the
argument setup of:
apply_ibt_endbr(__ibt_endbr_seal, __ibt_enbr_seal_end);
even when X86_KERNEL_IBT=n and the function is an empty stub, which leads
to link errors due to missing __ibt_endbr_seal* symbols:
ld: arch/x86/kernel/alternative.o: in function `alternative_instructions':
alternative.c:(.init.text+0x15d): undefined reference to `__ibt_endbr_seal_end'
ld: alternative.c:(.init.text+0x164): undefined reference to `__ibt_endbr_seal'
Remove the explicit 'noinline' to help gcc optimize them away.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221011113803.956808-1-linmiaohe@huawei.com
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The TVAL register is 32 bit signed. Thus only the lower 31 bits are
available to specify when an interrupt is to occur at some time in the
near future. Attempting to specify a larger interval with TVAL results
in a negative time delta which means the timer fires immediately upon
being programmed, rather than firing at that expected future time.
The solution is for Linux to declare that TVAL is a 31 bit register rather
than give its true size of 32 bits. This prevents Linux from programming
TVAL with a too-large value. Note that, prior to 5.16, this little trick
was the standard way to handle TVAL in Linux, so there is nothing new
happening here on that front.
The softlockup detector hides the issue, because it keeps generating
short timer deadlines that are within the scope of the broken timer.
Disable it, and you start using NO_HZ with much longer timer deadlines,
which turns into an interrupt flood:
11: 1124855130 949168462 758009394 76417474 104782230 30210281
310890 1734323687 GICv2 29 Level arch_timer
And "much longer" isn't that long: it takes less than 43s to underflow
TVAL at 50MHz (the frequency of the counter on XGene-1).
Some comments on the v1 version of this patch by Marc Zyngier:
XGene implements CVAL (a 64bit comparator) in terms of TVAL (a countdown
register) instead of the other way around. TVAL being a 32bit register,
the width of the counter should equally be 32. However, TVAL is a
*signed* value, and keeps counting down in the negative range once the
timer fires.
It means that any TVAL value with bit 31 set will fire immediately,
as it cannot be distinguished from an already expired timer. Reducing
the timer range back to a paltry 31 bits papers over the issue.
Another problem cannot be fixed though, which is that the timer interrupt
*must* be handled within the negative countdown period, or the interrupt
will be lost (TVAL will rollover to a positive value, indicative of a
new timer deadline).
Cc: stable@vger.kernel.org # 5.16+
Fixes: 012f18850452 ("clocksource/drivers/arm_arch_timer: Work around broken CVAL implementations")
Signed-off-by: Joe Korty <joe.korty@concurrent-rt.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
[maz: revamped the commit message]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221024165422.GA51107@zipoli.concurrent-rt.com
Link: https://lore.kernel.org/r/20221121145343.896018-1-maz@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org>
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In the WPCM450 SoC, the clocks for each timer can be gated individually.
To prevent the timer 1 clock from being gated, enable it explicitly.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20221104161850.2889894-3-j.neuschaefer@gmx.net
Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org>
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The timer module contains multiple timers. In the WPCM450 SoC, each timer
runs off a clock can be gated individually. To model this correctly, the
timer node in the devicetree needs to take multiple clock inputs.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20221104161850.2889894-2-j.neuschaefer@gmx.net
Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org>
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Add rockchip,rk3128-timer compatible string.
Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org>
Link: https://lore.kernel.org/r/0e57f38f-bace-8556-7258-aa0b3c0ac103@gmail.com
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The DYING/STARTING callbacks are not expected to fail. However, as reported
by Derek, buggy drivers such as tboot are still free to return errors
within those sections, which halts the hot(un)plug and leaves the CPU in an
unrecoverable state.
As there is no rollback possible, only log the failures and proceed with
the following steps.
This restores the hotplug behaviour prior to commit 453e41085183
("cpu/hotplug: Add cpuhp_invoke_callback_range()")
Fixes: 453e41085183 ("cpu/hotplug: Add cpuhp_invoke_callback_range()")
Reported-by: Derek Dolney <z23@posteo.net>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Derek Dolney <z23@posteo.net>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215867
Link: https://lore.kernel.org/r/20220927101259.1149636-1-vdonnefort@google.com
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Since the boot cpu does not go through the hotplug process it ends
up with state == CPUHP_ONLINE but target == CPUHP_OFFLINE.
So set the target to match in boot_cpu_hotplug_init().
Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/20221117162329.3164999-3-pauld@redhat.com
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Writing the current state back in hotplug/target calls cpu_down()
which will set cpu dying even when it isn't and then nothing will
ever clear it. A stress test that reads values and writes them back
for all cpu device files in sysfs will trigger the BUG() in
select_fallback_rq once all cpus are marked as dying.
kernel/cpu.c::target_store()
...
if (st->state < target)
ret = cpu_up(dev->id, target);
else
ret = cpu_down(dev->id, target);
cpu_down() -> cpu_set_state()
bool bringup = st->state < target;
...
if (cpu_dying(cpu) != !bringup)
set_cpu_dying(cpu, !bringup);
Fix this by letting state==target fall through in the target_store()
conditional. Also make sure st->target == target in that case.
Fixes: 757c989b9994 ("cpu/hotplug: Make target state writeable")
Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/20221117162329.3164999-2-pauld@redhat.com
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Delayed kobject debugging (CONFIG_DEBUG_KOBJECT_RELEASE) prints the kobject
pointer that's being released in kobject_release() before scheduling a
randomly delayed work to do the actual release work.
If the caller of kobject_put() frees the kobject upon return then this will
typically emit a debugobject warning about freeing an active timer.
Usually the release function is the function that does the kfree() of the
struct containing the kobject.
For example the following print is seen
kobject: 'queue' (ffff888114236190): kobject_release, parent 0000000000000000 (delayed 1000)
------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: timer_list hint: kobject_delayed_cleanup+0x0/0x390
but the kobject printk cannot be matched with the debug object printk
because it could be any number of kobjects that was released around that
time. The random delay for the work doesn't help either.
Print the address of the object being tracked to help to figure out which
kobject is the problem here. Note that this does not use %px here to match
the other %p usage in debugobject debugging. Due to %p usage it is required
to disable pointer hashing to correlate the two pointer printks.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220519202201.2348343-1-swboyd@chromium.org
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Commit ca16d5bee598 ("futex: Prevent robust futex exit race") addressed
two cases when tasks waiting on a robust non-PI futex remained blocked
despite the futex not being owned anymore:
* if the owner died after writing zero to the futex word, but before
waking up a waiter
* if a task waiting on the futex was woken up, but died before updating
the futex word (effectively swallowing the notification without acting
on it)
In the second case, the task could be woken up either by the previous
owner (after the futex word was reset to zero) or by the kernel (after
the OWNER_DIED bit was set and the TID part of the futex word was reset
to zero) if the previous owner died without the resetting the futex.
Because the referenced commit wakes up a potential waiter only if the
whole futex word is zero, the latter subcase remains unaddressed.
Fix this by looking only at the TID part of the futex when deciding
whether a wake up is needed.
Fixes: ca16d5bee598 ("futex: Prevent robust futex exit race")
Signed-off-by: Alexey Izbyshev <izbyshev@ispras.ru>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221111215439.248185-1-izbyshev@ispras.ru
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for_each_pci_dev() is implemented by pci_get_device(). The comment of
pci_get_device() says that it will increase the reference count for the
returned pci_dev and also decrease the reference count for the input
pci_dev @from if it is not NULL.
If we break for_each_pci_dev() loop with pdev not NULL, we need to call
pci_dev_put() to decrease the reference count. Add the missing
pci_dev_put() for the error path to avoid reference count leak.
Fixes: 2e4552893038 ("iommu/vt-d: Unify the way to process DMAR device scope array")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Link: https://lore.kernel.org/r/20221121113649.190393-3-wangxiongfeng2@huawei.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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for_each_pci_dev() is implemented by pci_get_device(). The comment of
pci_get_device() says that it will increase the reference count for the
returned pci_dev and also decrease the reference count for the input
pci_dev @from if it is not NULL.
If we break for_each_pci_dev() loop with pdev not NULL, we need to call
pci_dev_put() to decrease the reference count. Add the missing
pci_dev_put() before 'return true' to avoid reference count leak.
Fixes: 89a6079df791 ("iommu/vt-d: Force IOMMU on for platform opt in hint")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Link: https://lore.kernel.org/r/20221121113649.190393-2-wangxiongfeng2@huawei.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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As comment of pci_get_domain_bus_and_slot() says, it returns a pci device
with refcount increment, when finish using it, the caller must decrease
the reference count by calling pci_dev_put(). So call pci_dev_put() after
using the 'pdev' to avoid refcount leak.
Besides, if the 'pdev' is null or intel_svm_prq_report() returns error,
there is no need to trace this fault.
Fixes: 06f4b8d09dba ("iommu/vt-d: Remove unnecessary SVA data accesses in page fault path")
Suggested-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221119144028.2452731-1-yangyingliang@huawei.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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QAT devices on Intel Sapphire Rapids and Emerald Rapids have a defect in
address translation service (ATS). These devices may inadvertently issue
ATS invalidation completion before posted writes initiated with
translated address that utilized translations matching the invalidation
address range, violating the invalidation completion ordering.
This patch adds an extra device TLB invalidation for the affected devices,
it is needed to ensure no more posted writes with translated address
following the invalidation completion. Therefore, the ordering is
preserved and data-corruption is prevented.
Device TLBs are invalidated under the following six conditions:
1. Device driver does DMA API unmap IOVA
2. Device driver unbind a PASID from a process, sva_unbind_device()
3. PASID is torn down, after PASID cache is flushed. e.g. process
exit_mmap() due to crash
4. Under SVA usage, called by mmu_notifier.invalidate_range() where
VM has to free pages that were unmapped
5. userspace driver unmaps a DMA buffer
6. Cache invalidation in vSVA usage (upcoming)
For #1 and #2, device drivers are responsible for stopping DMA traffic
before unmap/unbind. For #3, iommu driver gets mmu_notifier to
invalidate TLB the same way as normal user unmap which will do an extra
invalidation. The dTLB invalidation after PASID cache flush does not
need an extra invalidation.
Therefore, we only need to deal with #4 and #5 in this patch. #1 is also
covered by this patch due to common code path with #5.
Tested-by: Yuzhang Luo <yuzhang.luo@intel.com>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Link: https://lore.kernel.org/r/20221130062449.1360063-1-jacob.jun.pan@linux.intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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Ronak Doshi says:
====================
vmxnet3: couple of fixes
This series fixes following issues:
Patch 1:
This patch provides a fix to correctly report encapsulated LRO'ed
packet.
Patch 2:
This patch provides a fix to use correct intrConf reference.
Changes in v2:
- declare generic descriptor to be used
- remove white spaces
- remove single quote around commit reference in patch 2
- remove if check for encap_lro
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Commit 39f9895a00f4 ("vmxnet3: add support for 32 Tx/Rx queues")
added support for 32Tx/Rx queues. As a part of this patch, intrConf
structure was extended to incorporate increased queues.
This patch fixes the issue where incorrect reference is being used.
Fixes: 39f9895a00f4 ("vmxnet3: add support for 32 Tx/Rx queues")
Signed-off-by: Ronak Doshi <doshir@vmware.com>
Acked-by: Guolin Yang <gyang@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Commit dacce2be3312 ("vmxnet3: add geneve and vxlan tunnel offload
support") added support for encapsulation offload. However, the
pathc did not report correctly the encapsulated packet which is
LRO'ed by the hypervisor.
This patch fixes this issue by using correct callback for the LRO'ed
encapsulated packet.
Fixes: dacce2be3312 ("vmxnet3: add geneve and vxlan tunnel offload support")
Signed-off-by: Ronak Doshi <doshir@vmware.com>
Acked-by: Guolin Yang <gyang@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Variable and return descriptions were missing from the SRCU read
lock functions. Add them.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/87zgcjpdvo.fsf@jogness.linutronix.de
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When setting up the early console, the setup() callback of the
regular console is used. It is called manually before registering
the early console instead of providing a setup() callback for the
early console. This is probably because the early setup needs a
different @options during the early stage.
The issue here is that the setup() callback is called without the
console_list_lock held and functions such as uart_set_options()
expect that.
Rather than manually calling the setup() function before registering,
provide an early console setup() callback that will use the different
early options. This ensures that the error checking, ordering, and
locking context when setting up the early console are correct.
Since this early console can only be registered via the earlyprintk=
parameter, the @options argument of the setup() callback will always
be NULL. Rather than simply ignoring the argument, add a WARN_ON()
to get our attention in case the setup() callback semantics should
change in the future.
Note that technically the current implementation works because it is
only used in early boot. And since the early console setup is
performed before registering, it cannot race with anything and thus
does not need any locking. However, longterm maintenance is easier
when drivers rely on the subsystem API rather than manually
implementing steps that could cause breakage in the future.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-41-john.ogness@linutronix.de
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The console_list_lock provides synchronization for console list and
console->flags updates. All call sites that were using the console_lock
for this synchronization have either switched to use the
console_list_lock or the SRCU list iterator.
Remove console_lock usage for console list updates and console->flags
updates.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-40-john.ogness@linutronix.de
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kgdboc_earlycon_init() uses the console_lock to ensure that no consoles
are unregistered until the kgdboc_earlycon is setup. The console_list_lock
should be used instead because list synchronization responsibility will
be removed from the console_lock in a later change.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-39-john.ogness@linutronix.de
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register_console()
Calling tty_find_polling_driver() can lead to uart_set_options() being
called (via the poll_init() callback of tty_operations) to configure the
uart. But uart_set_options() can also be called by register_console()
(via the setup() callback of console).
Take the console_list_lock to synchronize against register_console() and
also use it for console list traversal. This also ensures the console list
cannot change until the polling console has been chosen.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-38-john.ogness@linutronix.de
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configure_kgdboc() uses the console_lock for console list iteration. Use
the console_list_lock instead because list synchronization responsibility
will be removed from the console_lock in a later change.
The SRCU iterator could have been used here, but a later change will
relocate the locking of the console_list_lock to also provide
synchronization against register_console().
Note, the console_lock is still needed to serialize the device()
callback with other console operations.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-37-john.ogness@linutronix.de
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Use srcu console list iteration for safe console list traversal.
Note that this is a preparatory change for when console_lock no
longer provides synchronization for the console list.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-36-john.ogness@linutronix.de
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The console_lock is used in part to guarantee safe list iteration.
The console_list_lock should be used because list synchronization
responsibility will be removed from the console_lock in a later
change.
Note, the console_lock is still needed to serialize the device()
callback with other console operations.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-35-john.ogness@linutronix.de
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show_cons_active() uses the console_lock to gather information
on registered consoles. It requires that no consoles are unregistered
until it is finished. The console_list_lock should be used because
list synchronization responsibility will be removed from the
console_lock in a later change.
Note, the console_lock is still needed to serialize the device()
callback with other console operations.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-34-john.ogness@linutronix.de
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With commit 9e124fe16ff2("xen: Enable console tty by default in domU
if it's not a dummy") a hack was implemented to make sure that the
tty console remains the console behind the /dev/console device. The
main problem with the hack is that, after getting the console pointer
to the tty console, it is assumed the pointer is still valid after
releasing the console_sem. This assumption is incorrect and unsafe.
Make the hack safe by introducing a new function
console_force_preferred_locked() and perform the full operation
under the console_list_lock.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-33-john.ogness@linutronix.de
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The CON_ENABLED flag is being misused to track whether or not the
extended console should be or has been registered. Instead use
a local variable to decide if the extended console should be
registered and console_is_registered() to determine if it has
been registered.
Also add a check in cleanup_netconsole() to only unregister the
extended console if it has been registered.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-32-john.ogness@linutronix.de
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It is not reliable to check for CON_ENABLED in order to identify if a
console is registered. Use console_is_registered() instead.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-31-john.ogness@linutronix.de
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It is not reliable to check for CON_ENABLED in order to identify if a
console is registered. Use console_is_registered() instead.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-30-john.ogness@linutronix.de
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It is not reliable to check for CON_ENABLED in order to identify if a
console is registered. Use console_is_registered() instead.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-29-john.ogness@linutronix.de
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It is not reliable to check for CON_ENABLED in order to identify if a
console is registered. Use console_is_registered() instead.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-28-john.ogness@linutronix.de
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It is not reliable to check for CON_ENABLED in order to identify if a
console is registered. Use console_is_registered() instead.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-27-john.ogness@linutronix.de
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It is not reliable to check for CON_ENABLED in order to identify if a
console is registered. Use console_is_registered() instead.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-26-john.ogness@linutronix.de
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The CON_ENABLED status of a console is a runtime setting that does not
involve the console driver. Drivers must not assume that if the console
is disabled then proper hardware management is not needed. For the EFI
earlycon case, it is about remapping/unmapping memory for the
framebuffer.
Use console_is_registered() instead of checking CON_ENABLED.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-25-john.ogness@linutronix.de
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Currently CON_ENABLED is being (mis)used to identify if the console
has been registered. This is not reliable because it can be set even
though registration failed or it can be unset, even though the console
is registered. Use console_is_registered() instead.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-24-john.ogness@linutronix.de
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All users of uart_console_enabled() really want to know if a console
is registered. It is not reliable to check for CON_ENABLED in order
to identify if a console is registered. Use console_is_registered()
instead.
A _locked() variant is provided because uart_set_options() is always
called with the console_list_lock held and must check if a console
is registered in order to synchronize with kgdboc.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-23-john.ogness@linutronix.de
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Currently it is not possible for drivers to detect if they have
already successfully registered their console. Several drivers
have multiple paths that lead to console registration. To avoid
attempting a 2nd registration (which leads to a WARN), drivers
are implementing their own solution.
Introduce console_is_registered() so drivers can easily identify
if their console is currently registered. A _locked() variant
is also provided if the caller is already holding the
console_list_lock.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-22-john.ogness@linutronix.de
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Use srcu console list iteration for console list traversal. It is
acceptable because the consoles might come and go at any time.
Strict synchronizing with console registration code would not bring
any advantage over srcu.
Document why the console_lock is still necessary. Note that this
is a preparatory change for when console_lock no longer provides
synchronization for the console list.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-21-john.ogness@linutronix.de
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With SRCU it is now safe to traverse the console list, even if
the console_trylock() failed. However, overwriting console->seq
when console_trylock() failed is still an issue.
Switch to SRCU iteration and document remaining issue with
console->seq.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-20-john.ogness@linutronix.de
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Use srcu console list iteration for console list traversal.
Document why the console_lock is still necessary. Note that this
is a preparatory change for when console_lock no longer provides
synchronization for the console list.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-19-john.ogness@linutronix.de
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All users of console_is_usable() are SRCU iterators. Use the
appropriate wrapper function to locklessly read the flags.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-18-john.ogness@linutronix.de
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Use srcu console list iteration for console list traversal.
Document why the console_lock is still necessary. Note that this
is a preparatory change for when console_lock no longer provides
synchronization for the console list.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-17-john.ogness@linutronix.de
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Guarantee safe iteration of the console list by using SRCU.
Note that in the case of a handover, the SRCU read lock is also
released. This is documented in the function description and as
comments in the code. It is a bit tricky, but this preserves the
lockdep lock ordering for the context handing over the
console_lock:
console_lock()
| mutex_acquire(&console_lock_dep_map) <-- console lock
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console_unlock()
| console_flush_all()
| | srcu_read_lock(&console_srcu) <-- srcu lock
| | console_emit_next_record()
| | | console_lock_spinning_disable_and_check()
| | | | srcu_read_unlock(&console_srcu) <-- srcu unlock
| | | | mutex_release(&console_lock_dep_map) <-- console unlock
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-16-john.ogness@linutronix.de
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Guarantee safe iteration of the console list by using SRCU.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-15-john.ogness@linutronix.de
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Rather than using the console_lock to guarantee safe console list
traversal, use srcu console list iteration.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-14-john.ogness@linutronix.de
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After switching to SRCU for console list iteration, some readers
will begin readings console->flags as a data race. Locklessly
reading console->flags provides a consistent value because there
is at most one CPU modifying console->flags and that CPU is
using only read-modify-write operations.
Introduce a wrapper for SRCU iterators to read console flags.
Introduce a matching wrapper to write to flags of registered
consoles. Writing to flags of registered consoles is synchronized
by the console_list_lock.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-13-john.ogness@linutronix.de
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Currently there exist races in register_console(), where the types
of registered consoles are checked (without holding the console_lock)
and then after acquiring the console_lock, it is assumed that the list
has not changed. Also, some code that performs console_unregister()
make similar assumptions.
It might be possible to fix these races using the console_lock. But
it would require a complex analysis of all console drivers to make
sure that the console_lock is not taken in match() and setup()
callbacks. And we really prefer to split up and reduce the
responsibilities of console_lock rather than expand its complexity.
Therefore, introduce a new console_list_lock to provide full
synchronization for any console list changes.
In addition, also use console_list_lock for synchronization of
console->flags updates. All flags are either static or modified only
during the console registration. There are only two exceptions.
The first exception is CON_ENABLED, which is also modified by
console_start()/console_stop(). Therefore, these functions must
also take the console_list_lock.
The second exception is when the flags are modified by the console
driver init code before the console is registered. These will be
ignored because they are not visible to the rest of the system
via the console_drivers list.
Note that one of the various responsibilities of the console_lock is
also intended to provide console list and console->flags
synchronization. Later changes will update call sites relying on the
console_lock for these purposes. Once all call sites have been
updated, the console_lock will be relieved of synchronizing
console_list and console->flags updates.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/87sficwokr.fsf@jogness.linutronix.de
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The console_lock is held throughout the start/show/stop procedure
to print out device/driver information about all registered
consoles. Since the console_lock is being used for multiple reasons,
explicitly document these reasons. This will be useful when the
console_lock is split into fine-grained locking.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-11-john.ogness@linutronix.de
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