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23:31:00.8007 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: D1JpflfxICo8FoVeuFDcbylbFFsM5rl8y6s3A9UwQwS7CkHAJ1z4WmwQiFSaBG7GUbL7kvKfCJUp8VczLkr+xA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR11MB8658 X-OriginatorOrg: intel.com On Mon, Apr 13, 2026 at 06:39:23PM +0530, Sunny Patel wrote: > Fix two bugs in device migration paths: > > 1) migrate_vma_collect_huge_pmd() calls spin_unlock after > softleaf_entry_wait_on_locked(), which already releases the ptl. > > 2) migrate_vma_insert_huge_pmd_page() has a dead else-if branch and this > branch is always unreachable. > > Signed-off-by: Sunny Patel > --- > mm/migrate_device.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/mm/migrate_device.c b/mm/migrate_device.c > index 8079676c8f1f..0e005c26ee88 100644 > --- a/mm/migrate_device.c > +++ b/mm/migrate_device.c > @@ -177,7 +177,6 @@ static int migrate_vma_collect_huge_pmd(pmd_t *pmdp, unsigned long start, > > if (softleaf_is_migration(entry)) { > softleaf_entry_wait_on_locked(entry, ptl); > - spin_unlock(ptl); > return -EAGAIN; > } This entire if statement is dead code, since we bail out and collect a skip on !softleaf_is_device_private immediately above. I thought we already had a patch from Davidlohr Bueso 'mm/migrate_device: remove dead migration entry check in migrate_vma_collect_huge_pmd()' that removed this whole if statement. I even have an email from Andrew pulling this patch, but it looks like the code is still present in 7.0. I found this link via a google search which contains the above patch too: https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/25-new/+/f405e7bc5d93a541cf11663b2424baf0a03b496f%5E%21/ Look like this change got lost somehow? Matt > > @@ -869,8 +868,7 @@ static int migrate_vma_insert_huge_pmd_page(struct migrate_vma *migrate, > if (!is_huge_zero_pmd(*pmdp)) > goto unlock_abort; > flush = true; > - } else if (!pmd_none(*pmdp)) > - goto unlock_abort; > + } > > add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); > folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE); > -- > 2.43.0 >