Re: [PATCH] acpi: Fix possible recursive locking in hwregs.c

From: Rakib Mullick
Date: Wed Sep 21 2011 - 23:35:28 EST


On Thu, Sep 22, 2011 at 6:59 AM, Lin Ming <ming.m.lin@xxxxxxxxx> wrote:
> On Thu, Sep 22, 2011 at 2:09 AM, Rakib Mullick <rakib.mullick@xxxxxxxxx> wrote:
>> Calling pm-suspend might trigger a recursive lock in it's code path. In function acpi_hw_clear_acpi_status,
>> acpi_os_release_lock holds the lock acpi_gbl_hardware_lock before calling acpi_hw_register_write(), then
>> without releasing acpi_gbl_hardware_lock, this function calls acpi_ev_walk_gpe_list, which also tries to
>> hold acpi_gbl_hardware_lock and thus causes possible recursive lock.
>
> No, acpi_ev_walk_gpe_list holds acpi_gbl_gpe_lock.
>
Yes, right. Actually, acpi_os_release_lock() tries to hold
acpi_gbl_gpe_lock without releasing acpi_gbl_hardware_lock. Right?

Thanks,
Rakib
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