linux/kernel/trace/ring_buffer.c, branch v3.8

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-12-12T02:18:58Z

Pull perf fixes from Ingo Molnar: "These are late-v3.7 pending fixes for tracing." Fix up trivial conflict in kernel/trace/ring_buffer.c: the NULL pointer fix clashed with the change of type of the 'ret' variable. * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ring-buffer: Fix race between integrity check and readers ring-buffer: Fix NULL pointer if rb_set_head_page() fails ftrace: Clear bits properly in reset_iter_read()

ring-buffer: Fix race between integrity check and readers

2012-11-30T16:09:57Z

The function rb_check_pages() was added to make sure the ring buffer's pages were sane. This check is done when the ring buffer size is modified as well as when the iterator is released (closing the "trace" file), as that was considered a non fast path and a good place to do a sanity check. The problem is that the check does not have any locks around it. If one process were to read the trace file, and another were to read the raw binary file, the check could happen while the reader is reading the file. The issues with this is that the check requires to clear the HEAD page before doing the full check and it restores it afterward. But readers require the HEAD page to exist before it can read the buffer, otherwise it gives a nasty warning and disables the buffer. By adding the reader lock around the check, this keeps the race from happening. Cc: stable@vger.kernel.org # 3.6 Signed-off-by: Steven Rostedt

ring-buffer: Fix NULL pointer if rb_set_head_page() fails

2012-11-30T16:09:28Z

The function rb_set_head_page() searches the list of ring buffer pages for a the page that has the HEAD page flag set. If it does not find it, it will do a WARN_ON(), disable the ring buffer and return NULL, as this should never happen. But if this bug happens to happen, not all callers of this function can handle a NULL pointer being returned from it. That needs to be fixed. Cc: stable@vger.kernel.org # 3.0+ Signed-off-by: Steven Rostedt

ring-buffer: Change unsigned long type of ring_buffer_oldest_event_ts() to u64

2012-11-02T14:21:48Z

ring_buffer_oldest_event_ts() should return a value of u64 type, because ring_buffer_per_cpu->buffer_page->buffer_data_page->time_stamp is u64 type. Link: http://lkml.kernel.org/r/1349998076-15495-5-git-send-email-dhsharp@google.com Cc: Frederic Weisbecker Cc: Vaibhav Nagarnaik Signed-off-by: Yoshihiro YUNOMAE Signed-off-by: David Sharp Signed-off-by: Steven Rostedt

tracing: Trivial cleanup

2012-10-31T20:45:33Z

Remove ftrace_format_syscall() declaration; it is neither defined nor used. Also update a comment and formatting. Link: http://lkml.kernel.org/r/1339112785-21806-1-git-send-email-vnagarnaik@google.com Signed-off-by: David Sharp Signed-off-by: Vaibhav Nagarnaik Signed-off-by: Steven Rostedt

ring-buffer: Add a 'dropped events' counter

2012-10-31T20:45:27Z

The existing 'overrun' counter is incremented when the ring buffer wraps around, with overflow on (the default). We wanted a way to count requests lost from the buffer filling up with overflow off, too. I decided to add a new counter instead of retro-fitting the existing one because it seems like a different statistic to count conceptually, and also because of how the code was structured. Link: http://lkml.kernel.org/r/1310765038-26399-1-git-send-email-slavapestov@google.com Signed-off-by: Slava Pestov Signed-off-by: Steven Rostedt

ring-buffer: Check for uninitialized cpu buffer before resizing

2012-10-11T16:21:48Z

With a system where, num_present_cpus < num_possible_cpus, even if all CPUs are online, non-present CPUs don't have per_cpu buffers allocated. If per_cpu//buffer_size_kb is modified for such a CPU, it can cause a panic due to NULL dereference in ring_buffer_resize(). To fix this, resize operation is allowed only if the per-cpu buffer has been initialized. Link: http://lkml.kernel.org/r/1349912427-6486-1-git-send-email-vnagarnaik@google.com Cc: stable@vger.kernel.org # 3.5+ Signed-off-by: Vaibhav Nagarnaik Signed-off-by: Steven Rostedt

tracing/trivial: Fix some typos in kernel/trace

2012-08-07T13:43:32Z

Fix some typos in kernel/trace. Link: http://lkml.kernel.org/r/1343887320.2228.9.camel@louis-ThinkPad-T410 Signed-off-by: Wang Tianhong Signed-off-by: Steven Rostedt

Merge branch 'linus' into perf/core

2012-07-18T09:17:17Z

Pick up the latest ring-buffer fixes, before applying a new fix. Signed-off-by: Ingo Molnar

ring-buffer: Fix accounting of entries when removing pages

2012-06-29T20:17:17Z

When removing pages from the ring buffer, its state is not reset. This means that the counters need to be correctly updated to account for the pages removed. Update the overrun counter to reflect the removed events from the pages. Link: http://lkml.kernel.org/r/1340998301-1715-1-git-send-email-vnagarnaik@google.com Cc: Justin Teravest Cc: David Sharp Signed-off-by: Vaibhav Nagarnaik Signed-off-by: Steven Rostedt