CVE-2026-43311: soc/tegra: pmc: Fix unsafe generic_handle_irq() call

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

soc/tegra: pmc: Fix unsafe generic_handle_irq() call

Currently, when resuming from system suspend on Tegra platforms,
the following warning is observed:

WARNING: CPU: 0 PID: 14459 at kernel/irq/irqdesc.c:666
Call trace:
 handle_irq_desc+0x20/0x58 (P)
 tegra186_pmc_wake_syscore_resume+0xe4/0x15c
 syscore_resume+0x3c/0xb8
 suspend_devices_and_enter+0x510/0x540
 pm_suspend+0x16c/0x1d8

The warning occurs because generic_handle_irq() is being called from
a non-interrupt context which is considered as unsafe.

Fix this warning by deferring generic_handle_irq() call to an IRQ work
which gets executed in hard IRQ context where generic_handle_irq()
can be called safely.

When PREEMPT_RT kernels are used, regular IRQ work (initialized with
init_irq_work) is deferred to run in per-CPU kthreads in preemptible
context rather than hard IRQ context. Hence, use the IRQ_WORK_INIT_HARD
variant so that with PREEMPT_RT kernels, the IRQ work is processed in
hardirq context instead of being deferred to a thread which is required
for calling generic_handle_irq().

On non-PREEMPT_RT kernels, both init_irq_work() and IRQ_WORK_INIT_HARD()
execute in IRQ context, so this change has no functional impact for
standard kernel configurations.

[treding@nvidia.com: miscellaneous cleanups]

The Linux kernel CVE team has assigned CVE-2026-43311 to this issue.


Affected and fixed versions
===========================

	Fixed in 6.19.6 with commit 64016227dcdb968b7030eda04304f3d0df5d209d
	Fixed in 7.0 with commit e6d96073af681780820c94079b978474a8a44413

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-43311
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/soc/tegra/pmc.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/64016227dcdb968b7030eda04304f3d0df5d209d
	https://git.kernel.org/stable/c/e6d96073af681780820c94079b978474a8a44413