This is a note to let you know that I've just added the patch titled
ftrace/x86: One more missing sync after fixup of function modification
failure
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ftrace-x86-one-more-missing-sync-after-fixup-of-function-modification-failure.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From 12729f14d8357fb845d75155228b21e76360272d Mon Sep 17 00:00:00 2001
From: Petr Mladek <pmla...@suse.cz>
Date: Mon, 24 Feb 2014 17:12:20 +0100
Subject: ftrace/x86: One more missing sync after fixup of function modification
failure
From: Petr Mladek <pmla...@suse.cz>
commit 12729f14d8357fb845d75155228b21e76360272d upstream.
If a failure occurs while modifying ftrace function, it bails out and will
remove the tracepoints to be back to what the code originally was.
There is missing the final sync run across the CPUs after the fix up is done
and before the ftrace int3 handler flag is reset.
Here's the description of the problem:
CPU0 CPU1
---- ----
remove_breakpoint();
modifying_ftrace_code = 0;
[still sees breakpoint]
<takes trap>
[sees modifying_ftrace_code as zero]
[no breakpoint handler]
[goto failed case]
[trap exception - kernel breakpoint, no
handler]
BUG()
Link: http://lkml.kernel.org/r/1393258342-29978-2-git-send-email-pmla...@suse.cz
Fixes: 8a4d0a687a5 "ftrace: Use breakpoint method to update ftrace caller"
Acked-by: Frederic Weisbecker <fweis...@gmail.com>
Acked-by: H. Peter Anvin <h...@linux.intel.com>
Signed-off-by: Petr Mladek <pmla...@suse.cz>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/x86/kernel/ftrace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -659,8 +659,8 @@ ftrace_modify_code(unsigned long ip, uns
ret = -EPERM;
goto out;
}
- run_sync();
out:
+ run_sync();
return ret;
fail_update:
Patches currently in stable-queue which might be from pmla...@suse.cz are
queue-3.14/ftrace-x86-one-more-missing-sync-after-fixup-of-function-modification-failure.patch
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