redonkable
/
remarkable-linux
1
0
Fork 0
Code Releases Activity

blackfin/ptrace: call find_vma with the mmap_sem held 

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@hp.com>
Cc: Steven Miao <realmz6@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
wifi-calibration
Davidlohr Bueso 2014-06-06 14:38:10 -07:00 committed by Linus Torvalds
parent cccad5b983
commit b951242a4f
1 changed files with 6 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/blackfin/kernel/ptrace.c
View File

@ -117,6 +117,7 @@ put_reg(struct task_struct *task, unsigned long regno, unsigned long data)
int
is_user_addr_valid(struct task_struct *child, unsigned long start, unsigned long len)
{
bool valid;
struct vm_area_struct *vma;
struct sram_list_struct *sraml;
@ -124,9 +125,12 @@ is_user_addr_valid(struct task_struct *child, unsigned long start, unsigned long
if (start + len < start)
return -EIO;
down_read(&child->mm->mmap_sem);
vma = find_vma(child->mm, start);
if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
return 0;
valid = vma && start >= vma->vm_start && start + len <= vma->vm_end;
up_read(&child->mm->mmap_sem);
if (valid)
return 0;
for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
if (start >= (unsigned long)sraml->addr