RE: [PATCH] ACPICA: cleanup method properly on error

From: Zheng, Lv
Date: Fri Jul 29 2016 - 00:47:22 EST

Hi, Vegard

> From: linux-acpi-owner@xxxxxxxxxxxxxxx [mailto:linux-acpi-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Vegard Nossum
> Subject: [PATCH] ACPICA: cleanup method properly on error
> If the call to acpi_ds_init_aml_walk() fails, then we have to undo the
> walk state push done by acpi_ds_create_walk_state(). Otherwise, the new
> walk state (which has just been freed) will remain on the thread's
> walk_state_list and be dereferenced in acpi_ps_parse_aml() when we try
> to get the new state.
[Lv Zheng]
I haven't looked into the detail.
Let me first ask simple questions and present simple concerns in order to move this discussion on.

> You can observe this when reading e.g.
> /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0F:01/status
[Lv Zheng]
Do you mean you have real issues related to this?
If so, could provide the .config and dmesg for us?

> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
> ---
> drivers/acpi/acpica/dsmethod.c | 2 ++
> 1 file changed, 2 insertions(+)
> diff --git a/drivers/acpi/acpica/dsmethod.c
> b/drivers/acpi/acpica/dsmethod.c
> index 47c7b52..44b50a6 100644
> --- a/drivers/acpi/acpica/dsmethod.c
> +++ b/drivers/acpi/acpica/dsmethod.c
> @@ -596,6 +596,8 @@ cleanup:
> /* On error, we must terminate the method properly */
> acpi_ds_terminate_control_method(obj_desc, next_walk_state);
> + if (thread)
> + acpi_ds_pop_walk_state(thread);
> acpi_ds_delete_walk_state(next_walk_state);
[Lv Zheng]
It seems, if acpi_ds_create_walk_state() fails, acpi_ds_delete_walk_state() will be invoked.
So they are paired. Fixing this in acpi_ds_delete_walk_state() could help to fix all of them.
Given the fix is useful, why don't you do this in acpi_ds_delete_walk_state()?

Thanks and best regards