From: Steven Rostedt Date: Fri, 11 Dec 2009 04:20:52 +0000 (-0500) Subject: ring-buffer: Move resize integrity check under reader lock X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=dd7f59435782a02ceb6d16b9ce823dd3345d75ec;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git ring-buffer: Move resize integrity check under reader lock While using an application that does splice on the ftrace ring buffer at start up, I triggered an integrity check failure. Looking into this, I discovered that resizing the buffer performs an integrity check after the buffer is resized. This check unfortunately is preformed after it releases the reader lock. If a reader is reading the buffer it may cause the integrity check to trigger a false failure. This patch simply moves the integrity checker under the protection of the ring buffer reader lock. Signed-off-by: Steven Rostedt --- diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 0d64c51ab4df..eccb4cf1e998 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1208,9 +1208,9 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages) return; rb_reset_cpu(cpu_buffer); - spin_unlock_irq(&cpu_buffer->reader_lock); - rb_check_pages(cpu_buffer); + + spin_unlock_irq(&cpu_buffer->reader_lock); } static void @@ -1233,9 +1233,9 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer, list_add_tail(&bpage->list, cpu_buffer->pages); } rb_reset_cpu(cpu_buffer); - spin_unlock_irq(&cpu_buffer->reader_lock); - rb_check_pages(cpu_buffer); + + spin_unlock_irq(&cpu_buffer->reader_lock); } /**