On Mon, Mar 10, 2025 at 10:19:17AM +0000, Lorenzo Stoakes wrote: > On Thu, Mar 06, 2025 at 10:33:59AM +0000, Lorenzo Stoakes wrote: > > A number of mremap() calls both pass around and modify a large number of > > parameters, making the code less readable and often repeatedly having to > > determine things such as VMA, size delta, and more. > > [snip] > > Hi Andrew, > > I have a small fixpatch to address a corner case below, please apply! Actually, will respin so I can address Vlastimil's comments to make life easier! > > I have checked locally and this applies cleanly at this patch and causes no > merge conflicts when subsequent patches are applied on top. > > Thanks, Lorenzo > > ----8<---- > From 14a22fa872e19b468b6d06c15205efe77e460ce4 Mon Sep 17 00:00:00 2001 > From: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> > Date: Mon, 10 Mar 2025 10:13:17 +0000 > Subject: [PATCH] always check if !vma > > We perform VMA lookup in a couple more places which, in theory, can > unexpectedly fail to find a VMA. > > In these cases, correctly indicate failure. > > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> > Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> > Closes: https://lore.kernel.org/oe-lkp/202503101328.442cc724-lkp@xxxxxxxxx > --- > mm/mremap.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/mm/mremap.c b/mm/mremap.c > index 0ab0c88072a0..af022e3b89e2 100644 > --- a/mm/mremap.c > +++ b/mm/mremap.c > @@ -1066,10 +1066,13 @@ static unsigned long shrink_vma(struct vma_remap_struct *vrm, > * replace the invalidated VMA with the one that may have now been > * split. > */ > - if (drop_lock) > + if (drop_lock) { > vrm->mmap_locked = false; > - else > + } else { > vrm->vma = vma_lookup(mm, vrm->addr); > + if (!vrm->vma) > + return -EFAULT; > + } > > return 0; > } > @@ -1108,6 +1111,8 @@ static unsigned long mremap_to(struct vma_remap_struct *vrm) > * this can invalidate the old VMA. Reset. > */ > vrm->vma = vma_lookup(mm, vrm->addr); > + if (!vrm->vma) > + return -EFAULT; > } > > if (vrm->remap_type == MREMAP_SHRINK) { > -- > 2.48.1
