Re: [syzbot] [syzbot] [fs?] general protection fault in iter_file_splice_write

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Subject: [syzbot] [fs?] general protection fault in iter_file_splice_write
Author: lizhi.xu@xxxxxxxxxxxxx

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 33e02dc69afb

diff --git a/fs/splice.c b/fs/splice.c
index 60aed8de21f8..35a99fdabe9c 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -751,8 +751,18 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 
 		/* dismiss the fully eaten buffers, adjust the partial one */
 		tail = pipe->tail;
-		while (ret) {
+		while (ret > 0) {
 			struct pipe_buffer *buf = &pipe->bufs[tail & mask];
+			printk("ret: %d, nbufs: %d,  buf len: %u, m: %u, t: %u,ring size: %u, bufs len: %d, %s\n", ret, nbufs, buf->len, mask, tail, pipe->ring_size, ARRAY_SIZE(pipe->bufs), __func__);
+			if (ARRAY_SIZE(pipe->bufs) <= mask) {
+				ret = -EPIPE;
+				printk("oooh, %s\n", __func__);
+				break;
+			}
+			if (!buf->len) {
+				tail++;
+				continue;
+			}
 			if (ret >= buf->len) {
 				ret -= buf->len;
 				buf->len = 0;