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authorJann Horn <jannh@google.com>2020-10-15 20:13:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-16 11:11:22 -0700
commit4d45e75a9955ade5c2f49bd96fc4173b2cec9a72 (patch)
tree71b16b0e22ee630e2956a3285990fb49df84685e /mm
parent7f3bfab52cab96c510fd60dd757a32db7bc52d3c (diff)
mm: remove the now-unnecessary mmget_still_valid() hack
The preceding patches have ensured that core dumping properly takes the mmap_lock. Thanks to that, we can now remove mmget_still_valid() and all its users. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Link: http://lkml.kernel.org/r/20200827114932.3572699-8-jannh@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/khugepaged.c2
-rw-r--r--mm/madvise.c17
-rw-r--r--mm/mmap.c5
3 files changed, 2 insertions, 22 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 58b0d9c502a1..4e3dff13eb70 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -434,7 +434,7 @@ static void insert_to_mm_slots_hash(struct mm_struct *mm,
static inline int khugepaged_test_exit(struct mm_struct *mm)
{
- return atomic_read(&mm->mm_users) == 0 || !mmget_still_valid(mm);
+ return atomic_read(&mm->mm_users) == 0;
}
static bool hugepage_vma_check(struct vm_area_struct *vma,
diff --git a/mm/madvise.c b/mm/madvise.c
index 68b761c359d0..fd1f448b4e1d 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1085,23 +1085,6 @@ int do_madvise(unsigned long start, size_t len_in, int behavior)
if (write) {
if (mmap_write_lock_killable(current->mm))
return -EINTR;
-
- /*
- * We may have stolen the mm from another process
- * that is undergoing core dumping.
- *
- * Right now that's io_ring, in the future it may
- * be remote process management and not "current"
- * at all.
- *
- * We need to fix core dumping to not do this,
- * but for now we have the mmget_still_valid()
- * model.
- */
- if (!mmget_still_valid(current->mm)) {
- mmap_write_unlock(current->mm);
- return -EINTR;
- }
} else {
mmap_read_lock(current->mm);
}
diff --git a/mm/mmap.c b/mm/mmap.c
index 9fb9f8a233c7..ebb92f5515a1 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2562,7 +2562,7 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr)
if (vma && (vma->vm_start <= addr))
return vma;
/* don't alter vm_end if the coredump is running */
- if (!prev || !mmget_still_valid(mm) || expand_stack(prev, addr))
+ if (!prev || expand_stack(prev, addr))
return NULL;
if (prev->vm_flags & VM_LOCKED)
populate_vma_page_range(prev, addr, prev->vm_end, NULL);
@@ -2588,9 +2588,6 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr)
return vma;
if (!(vma->vm_flags & VM_GROWSDOWN))
return NULL;
- /* don't alter vm_start if the coredump is running */
- if (!mmget_still_valid(mm))
- return NULL;
start = vma->vm_start;
if (expand_stack(vma, addr))
return NULL;