On 29.11.2012 17:54, Alan Cox wrote:
>> diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
>> index 6c9b7cd..4f02f9c 100644
>> --- a/drivers/tty/tty_buffer.c
>> +++ b/drivers/tty/tty_buffer.c
>> @@ -114,11 +114,14 @@ static void __tty_buffer_flush(struct tty_struct *tty)
>> {
>> struct tty_buffer *thead;
>>
>> - while ((thead = tty->buf.head) != NULL) {
>> - tty->buf.head = thead->next;
>> - tty_buffer_free(tty, thead);
>> + if (tty->buf.head == NULL)
>> + return;
>> + while ((thead = tty->buf.head->next) != NULL) {
>> + tty_buffer_free(tty, tty->buf.head);
>> + tty->buf.head = thead;
>
> This part of the change seems to have no effect at all. There are no
> locks held so there is nothing guaranteeing how the other processors
> views of the order of operations will be affected.
>
> Alan
>
/**
* __tty_buffer_flush - flush full tty buffers
* @tty: tty to flush
*
* flush all the buffers containing receive data. Caller must
* hold the buffer lock and must have ensured no parallel flush to
* ldisc is running.
*
* Locking: Caller must hold tty->buf.lock
*/
Please, don't ignore my patch.
Please, Look at it one more time thoroughly.
Before REVERT [PATCH] tty: hold lock across tty buffer finding and buffer
filling.
Thank you.
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