On Thu, Mar 19, 2020 at 08:07:55PM -0400, Waiman Long wrote:

On 3/19/20 3:46 PM, Jarkko Sakkinen wrote:

quoted

On Wed, Mar 18, 2020 at 06:14:57PM -0400, Waiman Long wrote:

quoted

+			 * It is possible, though unlikely, that the key
+			 * changes in between the up_read->down_read period.
+			 * If the key becomes longer, we will have to
+			 * allocate a larger buffer and redo the key read
+			 * again.
+			 */
+			if (!tmpbuf || unlikely(ret > tmpbuflen)) {

Shouldn't you check that tmpbuflen stays below buflen (why else
you had made copy of buflen otherwise)?

The check above this thunk:

if ((ret > 0) && (ret <= buflen)) {

will make sure that ret will not be larger than buflen. So tmpbuflen
will never be bigger than buflen.

Ah right, of course, thanks.

What would go wrong if the condition was instead
((ret > 0) && (ret <= tmpbuflen))?

/Jarkko