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Rafael J. Wysocki
22db06337f
ACPI: sleep: Avoid breaking S3 wakeup due to might_sleep()
The addition of might_sleep() to down_timeout() caused the latter to enable interrupts unconditionally in some cases, which in turn broke the ACPI S3 wakeup path in acpi_suspend_enter(), where down_timeout() is called by acpi_disable_all_gpes() via acpi_ut_acquire_mutex(). Namely, if CONFIG_DEBUG_ATOMIC_SLEEP is set, might_sleep() causes might_resched() to be used and if CONFIG_PREEMPT_VOLUNTARY is set, this triggers __cond_resched() which may call preempt_schedule_common(), so __schedule() gets invoked and it ends up with enabled interrupts (in the prev == next case). Now, enabling interrupts early in the S3 wakeup path causes the kernel to crash. Address this by modifying acpi_suspend_enter() to disable GPEs without attempting to acquire the sleeping lock which is not needed in that code path anyway. Fixes: 99409b935c9a ("locking/semaphore: Add might_sleep() to down_*() family") Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: 5.15+ <stable@vger.kernel.org> # 5.15+
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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