CVE-2025-21803

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

LoongArch: Fix warnings during S3 suspend

The enable_gpe_wakeup() function calls acpi_enable_all_wakeup_gpes(), and the later one may call the preempt_schedule_common() function, resulting in a thread switch and causing the CPU to be in an interrupt enabled state after the enable_gpe_wakeup() function returns, leading to the warnings as follow.

[ C0] WARNING: ... at kernel/time/timekeeping.c:845 ktime_get+0xbc/0xc8 [ C0] ... [ C0] Call Trace: [ C0] [<90000000002243b4>] show_stack+0x64/0x188 [ C0] [<900000000164673c>] dump_stack_lvl+0x60/0x88 [ C0] [<90000000002687e4>] __warn+0x8c/0x148 [ C0] [<90000000015e9978>] report_bug+0x1c0/0x2b0 [ C0] [<90000000016478e4>] do_bp+0x204/0x3b8 [ C0] [<90000000025b1924>] exception_handlers+0x1924/0x10000 [ C0] [<9000000000343bbc>] ktime_get+0xbc/0xc8 [ C0] [<9000000000354c08>] tick_sched_timer+0x30/0xb0 [ C0] [<90000000003408e0>] __hrtimer_run_queues+0x160/0x378 [ C0] [<9000000000341f14>] hrtimer_interrupt+0x144/0x388 [ C0] [<9000000000228348>] constant_timer_interrupt+0x38/0x48 [ C0] [<90000000002feba4>] __handle_irq_event_percpu+0x64/0x1e8 [ C0] [<90000000002fed48>] handle_irq_event_percpu+0x20/0x80 [ C0] [<9000000000306b9c>] handle_percpu_irq+0x5c/0x98 [ C0] [<90000000002fd4a0>] generic_handle_domain_irq+0x30/0x48 [ C0] [<9000000000d0c7b0>] handle_cpu_irq+0x70/0xa8 [ C0] [<9000000001646b30>] handle_loongarch_irq+0x30/0x48 [ C0] [<9000000001646bc8>] do_vint+0x80/0xe0 [ C0] [<90000000002aea1c>] finish_task_switch.isra.0+0x8c/0x2a8 [ C0] [<900000000164e34c>] __schedule+0x314/0xa48 [ C0] [<900000000164ead8>] schedule+0x58/0xf0 [ C0] [<9000000000294a2c>] worker_thread+0x224/0x498 [ C0] [<900000000029d2f0>] kthread+0xf8/0x108 [ C0] [<9000000000221f28>] ret_from_kernel_thread+0xc/0xa4 [ C0] [ C0] ---[ end trace 0000000000000000 ]---

The root cause is acpi_enable_all_wakeup_gpes() uses a mutex to protect acpi_hw_enable_all_wakeup_gpes(), and acpi_ut_acquire_mutex() may cause a thread switch. Since there is no longer concurrent execution during loongarch_acpi_suspend(), we can call acpi_hw_enable_all_wakeup_gpes() directly in enable_gpe_wakeup().

The solution is similar to commit 22db06337f590d01 ("ACPI: sleep: Avoid breaking S3 wakeup due to might_sleep()").