From 973b645673b626beed3b20aedddf2ff51b8fcab8 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Fri, 22 Dec 2017 20:38:57 -0500 Subject: [PATCH] tracing: Remove extra zeroing out of the ring buffer page commit 6b7e633fe9c24682df550e5311f47fb524701586 upstream. The ring_buffer_read_page() takes care of zeroing out any extra data in the page that it returns. There's no need to zero it out again from the consumer. It was removed from one consumer of this function, but read_buffers_splice_read() did not remove it, and worse, it contained a nasty bug because of it. Fixes: 2711ca237a084 ("ring-buffer: Move zeroing out excess in page to ring buffer code") Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e61b862309af..10286ffd9112 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5502,7 +5502,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, .spd_release = buffer_spd_release, }; struct buffer_ref *ref; - int entries, size, i; + int entries, i; ssize_t ret = 0; mutex_lock(&trace_types_lock); @@ -5563,14 +5563,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, break; } - /* - * zero out any left over data, this is going to - * user land. - */ - size = ring_buffer_page_len(ref->page); - if (size < PAGE_SIZE) - memset(ref->page + size, 0, PAGE_SIZE - size); - page = virt_to_page(ref->page); spd.pages[i] = page; -- 2.43.0