This is a note to let you know that I've just added the patch titled
tracing: Fix fields of struct trace_iterator that are zeroed by mistake
to the 3.4-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:
tracing-fix-fields-of-struct-trace_iterator-that-are-zeroed-by-mistake.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From ed5467da0e369e65b247b99eb6403cb79172bcda Mon Sep 17 00:00:00 2001
From: Andrew Vagin <[email protected]>
Date: Fri, 2 Aug 2013 21:16:43 +0400
Subject: tracing: Fix fields of struct trace_iterator that are zeroed by mistake
From: Andrew Vagin <[email protected]>
commit ed5467da0e369e65b247b99eb6403cb79172bcda upstream.
tracing_read_pipe zeros all fields bellow "seq". The declaration contains
a comment about that, but it doesn't help.
The first field is "snapshot", it's true when current open file is
snapshot. Looks obvious, that it should not be zeroed.
The second field is "started". It was converted from cpumask_t to
cpumask_var_t (v2.6.28-4983-g4462344), in other words it was
converted from cpumask to pointer on cpumask.
Currently the reference on "started" memory is lost after the first read
from tracing_read_pipe and a proper object will never be freed.
The "started" is never dereferenced for trace_pipe, because trace_pipe
can't have the TRACE_FILE_ANNOTATE options.
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Andrew Vagin <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/ftrace_event.h | 4 +++-
kernel/trace/trace.c | 1 +
2 files changed, 4 insertions(+), 1 deletion(-)
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -71,6 +71,8 @@ struct trace_iterator {
/* trace_seq for __print_flags() and __print_symbolic() etc. */
struct trace_seq tmp_seq;
+ cpumask_var_t started;
+
/* The below is zeroed out in pipe_read */
struct trace_seq seq;
struct trace_entry *ent;
@@ -83,7 +85,7 @@ struct trace_iterator {
loff_t pos;
long idx;
- cpumask_var_t started;
+ /* All new field here will be zeroed out in pipe_read */
};
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3478,6 +3478,7 @@ waitagain:
memset(&iter->seq, 0,
sizeof(struct trace_iterator) -
offsetof(struct trace_iterator, seq));
+ cpumask_clear(iter->started);
iter->pos = -1;
trace_event_read_lock();
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/tracing-fix-fields-of-struct-trace_iterator-that-are-zeroed-by-mistake.patch
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