This is a note to let you know that I've just added the patch titled
NOMMU: Lock i_mmap_mutex for access to the VMA prio list
to the 3.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nommu-lock-i_mmap_mutex-for-access-to-the-vma-prio-list.patch
and it can be found in the queue-3.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 918e556ec214ed2f584e4cac56d7b29e4bb6bf27 Mon Sep 17 00:00:00 2001
From: David Howells <[email protected]>
Date: Thu, 23 Feb 2012 13:50:35 +0000
Subject: NOMMU: Lock i_mmap_mutex for access to the VMA prio list
From: David Howells <[email protected]>
commit 918e556ec214ed2f584e4cac56d7b29e4bb6bf27 upstream.
Lock i_mmap_mutex for access to the VMA prio list to prevent concurrent
access. Currently, certain parts of the mmap handling are protected by
the region mutex, but not all.
Reported-by: Al Viro <[email protected]>
Signed-off-by: David Howells <[email protected]>
Acked-by: Al Viro <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
mm/nommu.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -696,9 +696,11 @@ static void add_vma_to_mm(struct mm_stru
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
+ mutex_lock(&mapping->i_mmap_mutex);
flush_dcache_mmap_lock(mapping);
vma_prio_tree_insert(vma, &mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
+ mutex_unlock(&mapping->i_mmap_mutex);
}
/* add the VMA to the tree */
@@ -760,9 +762,11 @@ static void delete_vma_from_mm(struct vm
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
+ mutex_lock(&mapping->i_mmap_mutex);
flush_dcache_mmap_lock(mapping);
vma_prio_tree_remove(vma, &mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
+ mutex_unlock(&mapping->i_mmap_mutex);
}
/* remove from the MM's tree and list */
@@ -2052,6 +2056,7 @@ int nommu_shrink_inode_mappings(struct i
high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
down_write(&nommu_region_sem);
+ mutex_lock(&inode->i_mapping->i_mmap_mutex);
/* search for VMAs that fall within the dead zone */
vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
@@ -2059,6 +2064,7 @@ int nommu_shrink_inode_mappings(struct i
/* found one - only interested if it's shared out of the page
* cache */
if (vma->vm_flags & VM_SHARED) {
+ mutex_unlock(&inode->i_mapping->i_mmap_mutex);
up_write(&nommu_region_sem);
return -ETXTBSY; /* not quite true, but near enough */
}
@@ -2086,6 +2092,7 @@ int nommu_shrink_inode_mappings(struct i
}
}
+ mutex_unlock(&inode->i_mapping->i_mmap_mutex);
up_write(&nommu_region_sem);
return 0;
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.2/nommu-lock-i_mmap_mutex-for-access-to-the-vma-prio-list.patch
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