aboutsummaryrefslogtreecommitdiff
path: root/arch/arc
diff options
context:
space:
mode:
authorDavidlohr Bueso <davidlohr@hp.com>2014-06-04 16:07:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-04 16:54:00 -0700
commit5040573e49cc8f0e016a83544a0e552f2f44c897 (patch)
tree5c7db141f650f8d427d9e8984d2b4ead9e266635 /arch/arc
parent2ee06468702e0742114823a537510cd6f038cacc (diff)
downloadlinux-5040573e49cc8f0e016a83544a0e552f2f44c897.tar.gz
arc: 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. [akpm@linux-foundation.org: CSE current->active_mm, per Vineet] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arc')
-rw-r--r--arch/arc/kernel/troubleshoot.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/arc/kernel/troubleshoot.c b/arch/arc/kernel/troubleshoot.c
index 73a7450ee62..1badf9b84b5 100644
--- a/arch/arc/kernel/troubleshoot.c
+++ b/arch/arc/kernel/troubleshoot.c
@@ -86,12 +86,13 @@ static void show_faulting_vma(unsigned long address, char *buf)
unsigned long ino = 0;
dev_t dev = 0;
char *nm = buf;
+ struct mm_struct *active_mm = current->active_mm;
/* can't use print_vma_addr() yet as it doesn't check for
* non-inclusive vma
*/
-
- vma = find_vma(current->active_mm, address);
+ down_read(&active_mm->mmap_sem);
+ vma = find_vma(active_mm, address);
/* check against the find_vma( ) behaviour which returns the next VMA
* if the container VMA is not found
@@ -110,9 +111,10 @@ static void show_faulting_vma(unsigned long address, char *buf)
vma->vm_start < TASK_UNMAPPED_BASE ?
address : address - vma->vm_start,
nm, vma->vm_start, vma->vm_end);
- } else {
+ } else
pr_info(" @No matching VMA found\n");
- }
+
+ up_read(&active_mm->mmap_sem);
}
static void show_ecr_verbose(struct pt_regs *regs)