This is a note to let you know that I've just added the patch titled
tracing: Fix ent_size in trace output
to the 3.2-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-ent_size-in-trace-output.patch
and it can be found in the queue-3.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 12b5da349a8b94c9dbc3430a6bc42eabd9eaf50b Mon Sep 17 00:00:00 2001
From: Steven Rostedt <[email protected]>
Date: Tue, 27 Mar 2012 10:43:28 -0400
Subject: tracing: Fix ent_size in trace output
From: Steven Rostedt <[email protected]>
commit 12b5da349a8b94c9dbc3430a6bc42eabd9eaf50b upstream.
When reading the trace file, the records of each of the per_cpu buffers
are examined to find the next event to print out. At the point of looking
at the event, the size of the event is recorded. But if the first event is
chosen, the other events in the other CPU buffers will reset the event size
that is stored in the iterator descriptor, causing the event size passed to
the output functions to be incorrect.
In most cases this is not a problem, but for the case of stack traces, it
is. With the change to the stack tracing to record a dynamic number of
back traces, the output depends on the size of the entry instead of the
fixed 8 back traces. When the entry size is not correct, the back traces
would not be fully printed.
Note, reading from the per-cpu trace files were not affected.
Reported-by: Thomas Gleixner <[email protected]>
Tested-by: Thomas Gleixner <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/trace/trace.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1642,6 +1642,7 @@ __find_next_entry(struct trace_iterator
int cpu_file = iter->cpu_file;
u64 next_ts = 0, ts;
int next_cpu = -1;
+ int next_size = 0;
int cpu;
/*
@@ -1673,9 +1674,12 @@ __find_next_entry(struct trace_iterator
next_cpu = cpu;
next_ts = ts;
next_lost = lost_events;
+ next_size = iter->ent_size;
}
}
+ iter->ent_size = next_size;
+
if (ent_cpu)
*ent_cpu = next_cpu;
Patches currently in stable-queue which might be from [email protected] are
queue-3.2/tracing-fix-ent_size-in-trace-output.patch
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