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authorChristopher Yeoh <cyeoh@au1.ibm.com>2012-02-02 02:04:09 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2012-02-02 21:55:17 +0100
commit8cdb878dcb359fd1137e9abdee9322f5e9bcfdf8 (patch)
tree146afc01f3c1d7cbc944328484d077032bc53bfd /include
parentMerge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux (diff)
downloadlinux-8cdb878dcb359fd1137e9abdee9322f5e9bcfdf8.tar.xz
linux-8cdb878dcb359fd1137e9abdee9322f5e9bcfdf8.zip
Fix race in process_vm_rw_core
This fixes the race in process_vm_core found by Oleg (see http://article.gmane.org/gmane.linux.kernel/1235667/ for details). This has been updated since I last sent it as the creation of the new mm_access() function did almost exactly the same thing as parts of the previous version of this patch did. In order to use mm_access() even when /proc isn't enabled, we move it to kernel/fork.c where other related process mm access functions already are. Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/sched.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2234985a5e65..7d379a6bfd88 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2259,6 +2259,12 @@ static inline void mmdrop(struct mm_struct * mm)
extern void mmput(struct mm_struct *);
/* Grab a reference to a task's mm, if it is not already going away */
extern struct mm_struct *get_task_mm(struct task_struct *task);
+/*
+ * Grab a reference to a task's mm, if it is not already going away
+ * and ptrace_may_access with the mode parameter passed to it
+ * succeeds.
+ */
+extern struct mm_struct *mm_access(struct task_struct *task, unsigned int mode);
/* Remove the current tasks stale references to the old mm_struct */
extern void mm_release(struct task_struct *, struct mm_struct *);
/* Allocate a new mm structure and copy contents from tsk->mm */