On 9/21/26 6:35 PM, Yeoreum Yun wrote:
Although the child process in collapse_fork*() or collapse_max_ptes_shared()
reports `KSFT_FAIL`, the result is ignored because the test only checks
whether the parent’s page was collapsed into a huge page.

As a result, the test is considered successful whenever the parent’s page
is a huge page, even if the child test fails, as shown below:

   #
   # Run test: collapse_max_ptes_shared (khugepaged:anon)
   # Allocate huge page... OK
   # Share huge page over fork()... OK
   # Trigger CoW on page 1023 of 2048... OK
   # Maybe collapse with max_ptes_shared exceeded.... OK
   # Trigger CoW on page 1024 of 2048... Fail
   Bail out! Unexpected huge page
   # Planned tests != run tests (26 != 23)
   # Totals: pass:23 fail:0 xfail:0 xpass:0 skip:0 error:0  // child failed.
   # Check if parent still has huge page... OK              // parent hpage 
success
   ok 24 collapse_max_ptes_shared                           // considered as 
success
   ...
   # Totals: pass:26 fail:0 xfail:0 xpass:0 skip:0 error:0

To address this, propagate the child’s failure and skip the subsequent
check in the parent.

Signed-off-by: Yeoreum Yun <[email protected]>
---

Make sense to me.
Reviewed-by: Baolin Wang <[email protected]>

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