Commit 07906da7 authored by Rabin Vincent's avatar Rabin Vincent Committed by Steven Rostedt

tracing: Do not risk busy looping in buffer splice

If the read loop in trace_buffers_splice_read() keeps failing due to
memory allocation failures without reading even a single page then this
function will keep busy looping.

Remove the risk for that by exiting the function if memory allocation
failures are seen.

Link: http://lkml.kernel.org/r/1415309167-2373-2-git-send-email-rabin@rab.inSigned-off-by: default avatarRabin Vincent <rabin@rab.in>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent e30f53aa
......@@ -5494,7 +5494,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
};
struct buffer_ref *ref;
int entries, size, i;
ssize_t ret;
ssize_t ret = 0;
mutex_lock(&trace_types_lock);
......@@ -5532,13 +5532,16 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
int r;
ref = kzalloc(sizeof(*ref), GFP_KERNEL);
if (!ref)
if (!ref) {
ret = -ENOMEM;
break;
}
ref->ref = 1;
ref->buffer = iter->trace_buffer->buffer;
ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
if (!ref->page) {
ret = -ENOMEM;
kfree(ref);
break;
}
......@@ -5576,6 +5579,9 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
/* did we read anything? */
if (!spd.nr_pages) {
if (ret)
goto out;
if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) {
ret = -EAGAIN;
goto out;
......
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