On 10/30/19 9:31 PM, Andrew Morton wrote:
On Wed, 30 Oct 2019 11:14:58 -0700 Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> wrote:
On 10/30/19 9:58 AM, Yang Shi wrote:
The commit d883544515aa ("mm: mempolicy: make the behavior consistent
when MPOL_MF_MOVE* and MPOL_MF_STRICT were specified") fixed the return
value of mbind() for a couple of corner cases. But, it altered the
errno for some other cases, for example, mbind() should return -EFAULT
when part or all of the memory range specified by nodemask and maxnode
points outside your accessible address space, or there was an unmapped
hole in the specified memory range specified by addr and len.
Fixed this by preserving the errno returned by queue_pages_range().
And, the pagelist may be not empty even though queue_pages_range()
returns error, put the pages back to LRU since mbind_range() is not called
to really apply the policy so those pages should not be migrated, this
is also the old behavior before the problematic commit.
Forgot fixes tag.
Fixes: d883544515aa ("mm: mempolicy: make the behavior consistent when
MPOL_MF_MOVE* and MPOL_MF_STRICT were specified")
What's the relationship between this patch and
http://lkml.kernel.org/r/201910291756045288126@xxxxxxxxx?
They are irrelevant. The commit d883544515aa ("mm: mempolicy: make the
behavior consistent
when MPOL_MF_MOVE* and MPOL_MF_STRICT were specified") override the
-EFAULT return value of queue_pages_range() by -EIO mistakenly and
missed putting non-empty pagelist back, this patch is aimed to fix the
two issues.
I think Li Xinhai found the return value override problem during
debugging his patch.
