Re: [PATCH] mm/mremap: fix regression in vrm->new_addr check

[Vlastimil Babka <vbabka@suse.cz>]

On 8/28/25 16:29, Carlos Llamas wrote:
> On Thu, Aug 28, 2025 at 03:22:54PM +0100, Lorenzo Stoakes wrote:
>> On Thu, Aug 28, 2025 at 04:21:05PM +0200, Vlastimil Babka wrote:
>> > On 8/28/25 07:38, Lorenzo Stoakes wrote:
>> > > On Thu, Aug 28, 2025 at 03:26:52AM +0000, Carlos Llamas wrote:
>> > >> Commit 3215eaceca87 ("mm/mremap: refactor initial parameter sanity
>> > >> checks") moved the sanity check for vrm->new_addr from mremap_to() to
>> > >> check_mremap_params().
>> > >>
>> > >> However, this caused a regression as vrm->new_addr is now checked even
>> > >> when MREMAP_FIXED and MREMAP_DONTUNMAP flags are not specified. In this
>> > >> case, vrm->new_addr can be garbage and create unexpected failures.
>> > >
>> > > Yikes, sorry my mistake.
>> > >
>> > >>
>> > >> Fix this by moving the new_addr check after the vrm_implies_new_addr()
>> > >> guard. This ensures that the new_addr is only checked when the user has
>> > >> specified one explicitly.
>> > >>
>> > >> Fixes: 3215eaceca87 ("mm/mremap: refactor initial parameter sanity checks")
>> > >> Signed-off-by: Carlos Llamas <cmllamas@google.com>
>> > >
>> > > You need a Cc: Stable.
>> >
>> > No need as the commit being fixed is from 6.17-rc1?
>> > But it's better to use "[PATCH mm-hotfixes]" to make sure it goes to 6.17
>> > and not the next merge window.
>> >
>> 
>> Ah haha really? I'm losing track of my patches.
>> 
>> Yeah sure as per Vlasta then Carlos :)
> 
> Oops, sorry my v2 raced with this.

Nevermind, Andrew can fixup locally. Thanks :)