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-rw-r--r--fs/proc/task_mmu.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 92a91e7816d8..95ca1fe7283c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1143,6 +1143,24 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
count = -EINTR;
goto out_mm;
}
+ /*
+ * Avoid to modify vma->vm_flags
+ * without locked ops while the
+ * coredump reads the vm_flags.
+ */
+ if (!mmget_still_valid(mm)) {
+ /*
+ * Silently return "count"
+ * like if get_task_mm()
+ * failed. FIXME: should this
+ * function have returned
+ * -ESRCH if get_task_mm()
+ * failed like if
+ * get_proc_task() fails?
+ */
+ up_write(&mm->mmap_sem);
+ goto out_mm;
+ }
for (vma = mm->mmap; vma; vma = vma->vm_next) {
vma->vm_flags &= ~VM_SOFTDIRTY;
vma_set_page_prot(vma);