Re: [PATCH] mm/migrate_device: fix spinlock leak in migrate_vma_insert_huge_pmd_page

[Balbir Singh <balbirs@nvidia.com>]

On 4/25/26 23:54, Andrew Morton wrote:
> On Sat, 25 Apr 2026 19:05:27 +0530 Sunny Patel <nueralspacetech@gmail.com> wrote:
> 
>> When check_stable_address_space() fails after the PMD spinlock has
>> been acquired via pmd_lock(), the code jumps directly to the abort
>> label, bypassing the spin_unlock() call in unlock_abort. This causes
>> the PMD spinlock to be permanently held, leading to a deadlock.
>>
>> Change the goto target from abort to unlock_abort to ensure the
>> spinlock is always released on this error path.
>>
>> ...
>>
>> --- a/mm/migrate_device.c
>> +++ b/mm/migrate_device.c
>> @@ -850,7 +850,7 @@ static int migrate_vma_insert_huge_pmd_page(struct migrate_vma *migrate,
>>  	ptl = pmd_lock(vma->vm_mm, pmdp);
>>  	csa_ret = check_stable_address_space(vma->vm_mm);
>>  	if (csa_ret)
>> -		goto abort;
>> +		goto unlock_abort;
>>  
>>  	/*
>>  	 * Check for userfaultfd but do not deliver the fault. Instead,
> 
> whoops.
> 
> Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages")
> Cc: <stable@vger.kernel.org>


Thanks

Acked-by: Balbir Singh <balbirs@nvidia.com>