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-rw-r--r--kernel/trace/trace.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 9462976..1ce5dc6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3428,7 +3428,19 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
int size, i;
size_t ret;
- for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) {
+ if (*ppos & (PAGE_SIZE - 1)) {
+ WARN_ONCE(1, "Ftrace: previous read must page-align\n");
+ return -EINVAL;
+ }
+
+ if (len & (PAGE_SIZE - 1)) {
+ WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
+ if (len < PAGE_SIZE)
+ return -EINVAL;
+ len &= PAGE_MASK;
+ }
+
+ for (i = 0; i < PIPE_BUFFERS && len; i++, len -= PAGE_SIZE) {
struct page *page;
int r;
@@ -3467,7 +3479,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
spd.partial[i].offset = 0;
spd.partial[i].private = (unsigned long)ref;
spd.nr_pages++;
- *ppos += size;
+ *ppos += PAGE_SIZE;
}
spd.nr_pages = i;
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