[3.16.y-ckt stable] Patch "tracing: Fix unmapping loop in tracing_mark_write" has been added to staging queue
Luis Henriques
luis.henriques at canonical.com
Mon Mar 2 13:35:41 UTC 2015
This is a note to let you know that I have just added a patch titled
tracing: Fix unmapping loop in tracing_mark_write
to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue
This patch is scheduled to be released in version 3.16.7-ckt8.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From 366475b9c8ab44a17695c051c21c01bc47a9d925 Mon Sep 17 00:00:00 2001
From: Vikram Mulukutla <markivx at codeaurora.org>
Date: Wed, 17 Dec 2014 18:50:56 -0800
Subject: tracing: Fix unmapping loop in tracing_mark_write
commit 7215853e985a4bef1a6c14e00e89dfec84f1e457 upstream.
Commit 6edb2a8a385f0cdef51dae37ff23e74d76d8a6ce 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.org
Reviewed-by: Stephen Boyd <sboyd at codeaurora.org>
Reported-by: Lime Yang <limey at codeaurora.org>
Signed-off-by: Vikram Mulukutla <markivx at codeaurora.org>
Signed-off-by: Steven Rostedt <rostedt at goodmis.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
kernel/trace/trace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 01603e48742e..8b924fb7f915 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4894,7 +4894,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
*fpos += written;
out_unlock:
- for (i = 0; i < nr_pages; i++){
+ for (i = nr_pages - 1; i >= 0; i--) {
kunmap_atomic(map_page[i]);
put_page(pages[i]);
}
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