Subject: + m68k-call-find_vma-with-the-mmap_sem-held-in-sys_cacheflush.patch added to -mm tree
To: davidlohr@xxxxxx,geert@xxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 21 Apr 2014 14:20:42 -0700
The patch titled
Subject: m68k: call find_vma with the mmap_sem held in sys_cacheflush()
has been added to the -mm tree. Its filename is
m68k-call-find_vma-with-the-mmap_sem-held-in-sys_cacheflush.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/m68k-call-find_vma-with-the-mmap_sem-held-in-sys_cacheflush.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/m68k-call-find_vma-with-the-mmap_sem-held-in-sys_cacheflush.patch
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------------------------------------------------------
From: Davidlohr Bueso <davidlohr@xxxxxx>
Subject: m68k: call find_vma with the mmap_sem held in sys_cacheflush()
Performing vma lookups without taking the mm->mmap_sem is asking for
trouble. While doing the search, the vma in question can be modified or
even removed before returning to the caller. Take the lock (shared) in
order to avoid races while iterating through the vmacache and/or rbtree.
Signed-off-by: Davidlohr Bueso <davidlohr@xxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/m68k/kernel/sys_m68k.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff -puN arch/m68k/kernel/sys_m68k.c~m68k-call-find_vma-with-the-mmap_sem-held-in-sys_cacheflush arch/m68k/kernel/sys_m68k.c
--- a/arch/m68k/kernel/sys_m68k.c~m68k-call-find_vma-with-the-mmap_sem-held-in-sys_cacheflush
+++ a/arch/m68k/kernel/sys_m68k.c
@@ -376,7 +376,6 @@ cache_flush_060 (unsigned long addr, int
asmlinkage int
sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len)
{
- struct vm_area_struct *vma;
int ret = -EINVAL;
if (scope < FLUSH_SCOPE_LINE || scope > FLUSH_SCOPE_ALL ||
@@ -389,16 +388,23 @@ sys_cacheflush (unsigned long addr, int
if (!capable(CAP_SYS_ADMIN))
goto out;
} else {
+ struct vm_area_struct *vma;
+ bool invalid;
+
+ /* Check for overflow. */
+ if (addr + len < addr)
+ goto out;
+
/*
* Verify that the specified address region actually belongs
* to this process.
*/
- vma = find_vma (current->mm, addr);
ret = -EINVAL;
- /* Check for overflow. */
- if (addr + len < addr)
- goto out;
- if (vma == NULL || addr < vma->vm_start || addr + len > vma->vm_end)
+ down_read(¤t->mm->mmap_sem);
+ vma = find_vma(current->mm, addr);
+ invalid = !vma || addr < vma->vm_start || addr + len > vma->vm_end;
+ up_read(¤t->mm->mmap_sem);
+ if (invalid)
goto out;
}
_
Patches currently in -mm which might be from davidlohr@xxxxxx are
mmvmacache-add-debug-data.patch
mmvmacache-optimize-overflow-system-wide-flushing.patch
mm-pass-vm_bug_on-reason-to-dump_page.patch
mm-pass-vm_bug_on-reason-to-dump_page-fix.patch
hugetlb-prep_compound_gigantic_page-drop-__init-marker.patch
hugetlb-add-hstate_is_gigantic.patch
hugetlb-update_and_free_page-dont-clear-pg_reserved-bit.patch
hugetlb-move-helpers-up-in-the-file.patch
hugetlb-add-support-for-gigantic-page-allocation-at-runtime.patch
blackfin-ptrace-call-find_vma-with-the-mmap_sem-held.patch
m68k-call-find_vma-with-the-mmap_sem-held-in-sys_cacheflush.patch
mips-call-find_vma-with-the-mmap_sem-held.patch
arc-call-find_vma-with-the-mmap_sem-held.patch
driverssgi-gru-grufaultc-call-find_vma-with-the-mmap_sem-held.patch
drm-exynos-call-find_vma-with-the-mmap_sem-held.patch
ipc-constify-ipc_ops.patch
linux-next.patch
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