| Message ID | 20240717200709.1552558-20-Liam.Howlett@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Avoid MAP_FIXED gap exposure | expand |
On Wed, Jul 17, 2024 at 04:07:07PM GMT, Liam R. Howlett wrote: > From: "Liam R. Howlett" <Liam.Howlett@Oracle.com> > > The do_vma_munmap() wrapper existed for callers that didn't have a vma > iterator and needed to check the vma mseal status prior to calling the > underlying munmap(). All callers now use a vma iterator and since the > mseal check of can_modify_mm() has been moved to do_vmi_align_munmap() > and the vmas are aligned, this function can just be called instead. > > do_vmi_align_munmap() can no longer be static as ipc/shm is using it and > it is exported via the mm.h header. > > Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> > --- > include/linux/mm.h | 6 +++--- > ipc/shm.c | 8 ++++---- > mm/mmap.c | 33 +++++---------------------------- > 3 files changed, 12 insertions(+), 35 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 5f1075d19600..49a24c023153 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -3406,14 +3406,14 @@ extern unsigned long do_mmap(struct file *file, unsigned long addr, > extern int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, > unsigned long start, size_t len, struct list_head *uf, > bool unlock); > +extern int do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, > + struct mm_struct *mm, unsigned long start, > + unsigned long end, struct list_head *uf, bool unlock); Going to give the same nit as Vlasta gave to me ;) which is that I believe there's an unwritten rule that we drop the superfluous extern as we go here. Obviously this is not very important! :) > extern int do_munmap(struct mm_struct *, unsigned long, size_t, > struct list_head *uf); > extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior); > > #ifdef CONFIG_MMU > -extern int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, > - unsigned long start, unsigned long end, > - struct list_head *uf, bool unlock); > extern int __mm_populate(unsigned long addr, unsigned long len, > int ignore_errors); > static inline void mm_populate(unsigned long addr, unsigned long len) > diff --git a/ipc/shm.c b/ipc/shm.c > index 3e3071252dac..99564c870084 100644 > --- a/ipc/shm.c > +++ b/ipc/shm.c > @@ -1778,8 +1778,8 @@ long ksys_shmdt(char __user *shmaddr) > */ > file = vma->vm_file; > size = i_size_read(file_inode(vma->vm_file)); > - do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end, > - NULL, false); > + do_vmi_align_munmap(&vmi, vma, mm, vma->vm_start, > + vma->vm_end, NULL, false); > /* > * We discovered the size of the shm segment, so > * break out of here and fall through to the next > @@ -1803,8 +1803,8 @@ long ksys_shmdt(char __user *shmaddr) > if ((vma->vm_ops == &shm_vm_ops) && > ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) && > (vma->vm_file == file)) { > - do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end, > - NULL, false); > + do_vmi_align_munmap(&vmi, vma, mm, vma->vm_start, > + vma->vm_end, NULL, false); > } > > vma = vma_next(&vmi); > diff --git a/mm/mmap.c b/mm/mmap.c > index a32f545d3987..ca752317adef 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -269,11 +269,12 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) > goto out; /* mapping intersects with an existing non-brk vma. */ > /* > * mm->brk must be protected by write mmap_lock. > - * do_vma_munmap() will drop the lock on success, so update it > - * before calling do_vma_munmap(). > + * do_vmi_align_munmap() will drop the lock on success, so > + * update it before calling do_vma_munmap(). > */ > mm->brk = brk; > - if (do_vma_munmap(&vmi, brkvma, newbrk, oldbrk, &uf, true)) > + if (do_vmi_align_munmap(&vmi, brkvma, mm, newbrk, oldbrk, &uf, > + /* unlock = */ true)) > goto out; > > goto success_unlocked; > @@ -2865,7 +2866,7 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms, > * Return: 0 on success and drops the lock if so directed, error and leaves the > * lock held otherwise. > */ > -static int > +int > do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, > struct mm_struct *mm, unsigned long start, > unsigned long end, struct list_head *uf, bool unlock) > @@ -3348,30 +3349,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, > return ret; > } > > -/* > - * do_vma_munmap() - Unmap a full or partial vma. > - * @vmi: The vma iterator pointing at the vma > - * @vma: The first vma to be munmapped > - * @start: the start of the address to unmap > - * @end: The end of the address to unmap > - * @uf: The userfaultfd list_head > - * @unlock: Drop the lock on success > - * > - * unmaps a VMA mapping when the vma iterator is already in position. > - * Does not handle alignment. > - * > - * Return: 0 on success drops the lock of so directed, error on failure and will > - * still hold the lock. > - */ > -int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, > - unsigned long start, unsigned long end, struct list_head *uf, > - bool unlock) > -{ > - struct mm_struct *mm = vma->vm_mm; > - > - return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, unlock); > -} > - > /* > * do_brk_flags() - Increase the brk vma if the flags match. > * @vmi: The vma iterator > -- > 2.43.0 > This is a nice cleanup. LGTM, Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
diff --git a/include/linux/mm.h b/include/linux/mm.h index 5f1075d19600..49a24c023153 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3406,14 +3406,14 @@ extern unsigned long do_mmap(struct file *file, unsigned long addr, extern int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf, bool unlock); +extern int do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, + struct mm_struct *mm, unsigned long start, + unsigned long end, struct list_head *uf, bool unlock); extern int do_munmap(struct mm_struct *, unsigned long, size_t, struct list_head *uf); extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior); #ifdef CONFIG_MMU -extern int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, - unsigned long start, unsigned long end, - struct list_head *uf, bool unlock); extern int __mm_populate(unsigned long addr, unsigned long len, int ignore_errors); static inline void mm_populate(unsigned long addr, unsigned long len) diff --git a/ipc/shm.c b/ipc/shm.c index 3e3071252dac..99564c870084 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -1778,8 +1778,8 @@ long ksys_shmdt(char __user *shmaddr) */ file = vma->vm_file; size = i_size_read(file_inode(vma->vm_file)); - do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end, - NULL, false); + do_vmi_align_munmap(&vmi, vma, mm, vma->vm_start, + vma->vm_end, NULL, false); /* * We discovered the size of the shm segment, so * break out of here and fall through to the next @@ -1803,8 +1803,8 @@ long ksys_shmdt(char __user *shmaddr) if ((vma->vm_ops == &shm_vm_ops) && ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) && (vma->vm_file == file)) { - do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end, - NULL, false); + do_vmi_align_munmap(&vmi, vma, mm, vma->vm_start, + vma->vm_end, NULL, false); } vma = vma_next(&vmi); diff --git a/mm/mmap.c b/mm/mmap.c index a32f545d3987..ca752317adef 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -269,11 +269,12 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) goto out; /* mapping intersects with an existing non-brk vma. */ /* * mm->brk must be protected by write mmap_lock. - * do_vma_munmap() will drop the lock on success, so update it - * before calling do_vma_munmap(). + * do_vmi_align_munmap() will drop the lock on success, so + * update it before calling do_vma_munmap(). */ mm->brk = brk; - if (do_vma_munmap(&vmi, brkvma, newbrk, oldbrk, &uf, true)) + if (do_vmi_align_munmap(&vmi, brkvma, mm, newbrk, oldbrk, &uf, + /* unlock = */ true)) goto out; goto success_unlocked; @@ -2865,7 +2866,7 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms, * Return: 0 on success and drops the lock if so directed, error and leaves the * lock held otherwise. */ -static int +int do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, struct mm_struct *mm, unsigned long start, unsigned long end, struct list_head *uf, bool unlock) @@ -3348,30 +3349,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, return ret; } -/* - * do_vma_munmap() - Unmap a full or partial vma. - * @vmi: The vma iterator pointing at the vma - * @vma: The first vma to be munmapped - * @start: the start of the address to unmap - * @end: The end of the address to unmap - * @uf: The userfaultfd list_head - * @unlock: Drop the lock on success - * - * unmaps a VMA mapping when the vma iterator is already in position. - * Does not handle alignment. - * - * Return: 0 on success drops the lock of so directed, error on failure and will - * still hold the lock. - */ -int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, - unsigned long start, unsigned long end, struct list_head *uf, - bool unlock) -{ - struct mm_struct *mm = vma->vm_mm; - - return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, unlock); -} - /* * do_brk_flags() - Increase the brk vma if the flags match. * @vmi: The vma iterator