Re: [PATCH v4 1/5] ACPICA: Namespace: Fix a regression that MLC support triggers dead lock in dynamic table loading

From: Mika Westerberg
Date: Tue Jun 21 2016 - 04:06:03 EST


On Tue, Jun 21, 2016 at 12:34:15PM +0800, Lv Zheng wrote:
> The new MLC approach invokes MLC per-table basis. But the dynamic loading
> support of this is incorrect because of the lock order:
> acpi_ns_evaluate
> acpi_ex_enter_intperter
> acpi_ns_load_table (triggered by Load opcode)
> acpi_ns_exec_module_code_list
> acpi_ex_enter_intperter
> The regression is introduced by the following commit:
> Commit: 2785ce8d0da1cac9d8f78615e116cf929e9a9123
> ACPICA Commit: 071eff738c59eda1792ac24b3b688b61691d7e7c
> Subject: ACPICA: Add per-table execution of module-level code
> This patch fixes this regression by unlocking the interpreter lock before
> invoking MLC. However the unlocking is done to the acpi_ns_load_table(), in
> which, the interpreter lock should be locked by acpi_ns_parse_table() but
> wasn't. Reported by Mika Westerberg. Fixed by Lv Zheng.
>
> Fixes: 2785ce8d0da1 ("ACPICA: Add per-table execution of module-level code")
> Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> Reported-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>

Now builds fine and fixes the hang, thanks :)

Tested-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>