commit ca6b0bf0e086513b9ee5efc0aa5770ecb57778af
author Al Viro <viro@zeniv.linux.org.uk> Tue Feb 15 22:04:37 2011 -0500
committer Al Viro <viro@zeniv.linux.org.uk> Wed Mar 23 16:36:50 2011 -0400
tree 4fec50b38253288746ac4b4ea6d4bf5216b0c53b
parent 26ec3c646e75ce7a69fda429d68fcbdcd5eacc62

pagemap: close races with suid execve

just use mm_for_maps()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/proc/task_mmu.c

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 60b9148..c966413 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -729,7 +729,8 @@
 		goto out;
 
 	ret = -EACCES;
-	if (!ptrace_may_access(task, PTRACE_MODE_READ))
+	mm = mm_for_maps(task);
+	if (!mm)
 		goto out_task;
 
 	ret = -EINVAL;
@@ -742,10 +743,6 @@
 	if (!count)
 		goto out_task;
 
-	mm = get_task_mm(task);
-	if (!mm)
-		goto out_task;
-
 	pm.len = PM_ENTRY_BYTES * (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
 	pm.buffer = kmalloc(pm.len, GFP_TEMPORARY);
 	ret = -ENOMEM;