3.18-stable patches

added patches:
	ring_buffer-tracing-inherit-the-tracing-setting-to-next-ring-buffer.patch

diff --git a/queue-3.18/ring_buffer-tracing-inherit-the-tracing-setting-to-next-ring-buffer.patch b/queue-3.18/ring_buffer-tracing-inherit-the-tracing-setting-to-next-ring-buffer.patch
new file mode 100644 (file)
index 0000000..e70bc8c
--- /dev/null
+++ b/queue-3.18/ring_buffer-tracing-inherit-the-tracing-setting-to-next-ring-buffer.patch
@@ -0,0 +1,103 @@
+From 73c8d8945505acdcbae137c2e00a1232e0be709f Mon Sep 17 00:00:00 2001
+From: Masami Hiramatsu <mhiramat@kernel.org>
+Date: Sat, 14 Jul 2018 01:28:15 +0900
+Subject: ring_buffer: tracing: Inherit the tracing setting to next ring buffer
+
+From: Masami Hiramatsu <mhiramat@kernel.org>
+
+commit 73c8d8945505acdcbae137c2e00a1232e0be709f upstream.
+
+Maintain the tracing on/off setting of the ring_buffer when switching
+to the trace buffer snapshot.
+
+Taking a snapshot is done by swapping the backup ring buffer
+(max_tr_buffer). But since the tracing on/off setting is defined
+by the ring buffer, when swapping it, the tracing on/off setting
+can also be changed. This causes a strange result like below:
+
+  /sys/kernel/debug/tracing # cat tracing_on
+  1
+  /sys/kernel/debug/tracing # echo 0 > tracing_on
+  /sys/kernel/debug/tracing # cat tracing_on
+  0
+  /sys/kernel/debug/tracing # echo 1 > snapshot
+  /sys/kernel/debug/tracing # cat tracing_on
+  1
+  /sys/kernel/debug/tracing # echo 1 > snapshot
+  /sys/kernel/debug/tracing # cat tracing_on
+  0
+
+We don't touch tracing_on, but snapshot changes tracing_on
+setting each time. This is an anomaly, because user doesn't know
+that each "ring_buffer" stores its own tracing-enable state and
+the snapshot is done by swapping ring buffers.
+
+Link: http://lkml.kernel.org/r/153149929558.11274.11730609978254724394.stgit@devbox
+
+Cc: Ingo Molnar <mingo@redhat.com>
+Cc: Shuah Khan <shuah@kernel.org>
+Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
+Cc: Hiraku Toyooka <hiraku.toyooka@cybertrust.co.jp>
+Cc: stable@vger.kernel.org
+Fixes: debdd57f5145 ("tracing: Make a snapshot feature available from userspace")
+Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
+[ Updated commit log and comment in the code ]
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/linux/ring_buffer.h |    1 +
+ kernel/trace/ring_buffer.c  |   16 ++++++++++++++++
+ kernel/trace/trace.c        |    6 ++++++
+ 3 files changed, 23 insertions(+)
+
+--- a/include/linux/ring_buffer.h
++++ b/include/linux/ring_buffer.h
+@@ -162,6 +162,7 @@ void ring_buffer_record_enable(struct ri
+ void ring_buffer_record_off(struct ring_buffer *buffer);
+ void ring_buffer_record_on(struct ring_buffer *buffer);
+ int ring_buffer_record_is_on(struct ring_buffer *buffer);
++int ring_buffer_record_is_set_on(struct ring_buffer *buffer);
+ void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
+ void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
+ 
+--- a/kernel/trace/ring_buffer.c
++++ b/kernel/trace/ring_buffer.c
+@@ -3153,6 +3153,22 @@ int ring_buffer_record_is_on(struct ring
+ }
+ 
+ /**
++ * ring_buffer_record_is_set_on - return true if the ring buffer is set writable
++ * @buffer: The ring buffer to see if write is set enabled
++ *
++ * Returns true if the ring buffer is set writable by ring_buffer_record_on().
++ * Note that this does NOT mean it is in a writable state.
++ *
++ * It may return true when the ring buffer has been disabled by
++ * ring_buffer_record_disable(), as that is a temporary disabling of
++ * the ring buffer.
++ */
++int ring_buffer_record_is_set_on(struct ring_buffer *buffer)
++{
++      return !(atomic_read(&buffer->record_disabled) & RB_BUFFER_OFF);
++}
++
++/**
+  * ring_buffer_record_disable_cpu - stop all writes into the cpu_buffer
+  * @buffer: The ring buffer to stop writes to.
+  * @cpu: The CPU buffer to stop
+--- a/kernel/trace/trace.c
++++ b/kernel/trace/trace.c
+@@ -1023,6 +1023,12 @@ update_max_tr(struct trace_array *tr, st
+ 
+       arch_spin_lock(&tr->max_lock);
+ 
++      /* Inherit the recordable setting from trace_buffer */
++      if (ring_buffer_record_is_set_on(tr->trace_buffer.buffer))
++              ring_buffer_record_on(tr->max_buffer.buffer);
++      else
++              ring_buffer_record_off(tr->max_buffer.buffer);
++
+       buf = tr->trace_buffer.buffer;
+       tr->trace_buffer.buffer = tr->max_buffer.buffer;
+       tr->max_buffer.buffer = buf;

diff --git a/queue-3.18/series b/queue-3.18/series
index d84200e911684a802f44a28a8b599a5b8526e028..856978630aeed1f7df8c61efa22bc6d07636e9e4 100644 (file)
--- a/queue-3.18/series
+++ b/queue-3.18/series
@@ -81,3 +81,4 @@ crypto-padlock-aes-fix-nano-workaround-data-corruption.patch
 scsi-sg-fix-minor-memory-leak-in-error-path.patch
 scsi-qla2xxx-fix-isp-recovery-on-unload.patch
 scsi-qla2xxx-return-error-when-tmf-returns.patch
+ring_buffer-tracing-inherit-the-tracing-setting-to-next-ring-buffer.patch