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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-02-01 10:43:01 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-02-01 10:43:01 -0800 |
commit | 935cc9323ac33bb9b6cb853815e5c86f77e50607 (patch) | |
tree | 6b48024b35b2d166de592ab3238e80c3e763f46a /kernel | |
parent | 4ca5ded2bdc09259ad89915bac2d218e72cda351 (diff) | |
parent | 03688970347bfea32823953a7ce5886d1713205f (diff) | |
download | op-kernel-dev-935cc9323ac33bb9b6cb853815e5c86f77e50607.zip op-kernel-dev-935cc9323ac33bb9b6cb853815e5c86f77e50607.tar.gz |
Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tracing/documentation: Cover new frame pointer semantics
tracing/documentation: Fix a typo in ftrace.txt
ring-buffer: Check for end of page in iterator
ring-buffer: Check if ring buffer iterator has stale data
tracing: Prevent kernel oops with corrupted buffer
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/Kconfig | 4 | ||||
-rw-r--r-- | kernel/trace/ring_buffer.c | 24 | ||||
-rw-r--r-- | kernel/trace/trace.c | 5 |
3 files changed, 27 insertions, 6 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 6c22d8a..60e2ce0 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -27,9 +27,7 @@ config HAVE_FUNCTION_GRAPH_TRACER config HAVE_FUNCTION_GRAPH_FP_TEST bool help - An arch may pass in a unique value (frame pointer) to both the - entering and exiting of a function. On exit, the value is compared - and if it does not match, then it will panic the kernel. + See Documentation/trace/ftrace-design.txt config HAVE_FUNCTION_TRACE_MCOUNT_TEST bool diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index edefe3b..8c1b2d2 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -464,6 +464,8 @@ struct ring_buffer_iter { struct ring_buffer_per_cpu *cpu_buffer; unsigned long head; struct buffer_page *head_page; + struct buffer_page *cache_reader_page; + unsigned long cache_read; u64 read_stamp; }; @@ -2716,6 +2718,8 @@ static void rb_iter_reset(struct ring_buffer_iter *iter) iter->read_stamp = cpu_buffer->read_stamp; else iter->read_stamp = iter->head_page->page->time_stamp; + iter->cache_reader_page = cpu_buffer->reader_page; + iter->cache_read = cpu_buffer->read; } /** @@ -3060,13 +3064,22 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) struct ring_buffer_event *event; int nr_loops = 0; - if (ring_buffer_iter_empty(iter)) - return NULL; - cpu_buffer = iter->cpu_buffer; buffer = cpu_buffer->buffer; + /* + * Check if someone performed a consuming read to + * the buffer. A consuming read invalidates the iterator + * and we need to reset the iterator in this case. + */ + if (unlikely(iter->cache_read != cpu_buffer->read || + iter->cache_reader_page != cpu_buffer->reader_page)) + rb_iter_reset(iter); + again: + if (ring_buffer_iter_empty(iter)) + return NULL; + /* * We repeat when a timestamp is encountered. * We can get multiple timestamps by nested interrupts or also @@ -3081,6 +3094,11 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) if (rb_per_cpu_empty(cpu_buffer)) return NULL; + if (iter->head >= local_read(&iter->head_page->page->commit)) { + rb_inc_iter(iter); + goto again; + } + event = rb_iter_head_event(iter); switch (event->type_len) { diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0df1b0f..eac6875 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -951,6 +951,11 @@ void trace_find_cmdline(int pid, char comm[]) return; } + if (WARN_ON_ONCE(pid < 0)) { + strcpy(comm, "<XXX>"); + return; + } + if (pid > PID_MAX_DEFAULT) { strcpy(comm, "<...>"); return; |