The intention of commit aae8679b0ebcaa92f99c1c3cb0cd651594a43915 was to
force reads of /proc/pid/pagemap to be a multiple of 8 bytes, but now it
allows to read 0 bytes, which actually puts some data to user's buffer.
According to POSIX, if count is zero, read() should return zero and has
no other results.
Signed-off-by: Vitaly Mayatskikh <[email protected]>
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 39e4ad4..6f61b7c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -665,6 +665,10 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
goto out_task;
ret = 0;
+
+ if (!count)
+ goto out_task;
+
mm = get_task_mm(task);
if (!mm)
goto out_task;
--
wbr, Vitaly