On Friday, November 15, 2013 11:41:29 AM Olof Johansson wrote:
> From: Puneet Kumar <puneetster@xxxxxxxxxxxx>
>
> A bug was introduced by commit b76b51ba0cef ('ACPI / EC: Add more debug
> info and trivial code cleanup') that erroneously caused the struct member
> to be accessed before acquiring the required lock. This change fixes
> it by ensuring the lock acquisition is done first.
>
> Found by Aaron Durbin <adurbin@xxxxxxxxxxxx>
>
> Fixes: b76b51ba0cef ('ACPI / EC: Add more debug info and trivial code cleanup')
> References: http://crbug.com/319019
> Signed-off-by: Puneet Kumar <puneetster@xxxxxxxxxxxx>
> Reviewed-by: Aaron Durbin <adurbin@xxxxxxxxxxxx>
> [olof: Commit message reworded a bit]
> Signed-off-by: Olof Johansson <olof@xxxxxxxxx>
> Cc: Feng Tang <feng.tang@xxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # 3.8+
Queued up for the next ACPI pull request, thanks guys!
> ---
> drivers/acpi/ec.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
> index d5309fd..ba5b56d 100644
> --- a/drivers/acpi/ec.c
> +++ b/drivers/acpi/ec.c
> @@ -173,9 +173,10 @@ static void start_transaction(struct acpi_ec *ec)
> static void advance_transaction(struct acpi_ec *ec, u8 status)
> {
> unsigned long flags;
> - struct transaction *t = ec->curr;
> + struct transaction *t;
>
> spin_lock_irqsave(&ec->lock, flags);
> + t = ec->curr;
> if (!t)
> goto unlock;
> if (t->wlen > t->wi) {
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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