Commit 366475b9 authored by Vikram Mulukutla's avatar Vikram Mulukutla Committed by Luis Henriques

tracing: Fix unmapping loop in tracing_mark_write

commit 7215853e upstream.

Commit 6edb2a8a introduced
an array map_pages that contains the addresses returned by
kmap_atomic. However, when unmapping those pages, map_pages[0]
is unmapped before map_pages[1], breaking the nesting requirement
as specified in the documentation for kmap_atomic/kunmap_atomic.

This was caught by the highmem debug code present in kunmap_atomic.
Fix the loop to do the unmapping properly.

Link: http://lkml.kernel.org/r/1418871056-6614-1-git-send-email-markivx@codeaurora.orgReviewed-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Reported-by: default avatarLime Yang <limey@codeaurora.org>
Signed-off-by: default avatarVikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 3b3c7a2a
...@@ -4894,7 +4894,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, ...@@ -4894,7 +4894,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
*fpos += written; *fpos += written;
out_unlock: out_unlock:
for (i = 0; i < nr_pages; i++){ for (i = nr_pages - 1; i >= 0; i--) {
kunmap_atomic(map_page[i]); kunmap_atomic(map_page[i]);
put_page(pages[i]); put_page(pages[i]);
} }
......
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