From 1ea18fa8a3ab961ea43610e22dda3c87e8f2a67a Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Wed, 3 Apr 2024 09:25:43 +0200 Subject: [PATCH] BUG/MAJOR: applet: fix a MIN vs MAX usage in appctx_raw_rcv_buf() The MAX() macro was used to limit the count of bytes to be transferred in appctx_raw_rcv_buf() by commit ee53d8421f ("MEDIUM: applet: Simplify a bit API to exchange data with applets") instead of MIN(). It didn't seem to have any consequences until commit f37ddbeb4b ("MAJOR: cli: Update the CLI applet to handle its own buffers") that triggers a BUG_ON() in __b_putblk() when the other side is slow to read, because we're trying to append a full buffer on top of a non-empty one. A way to reproduce it is to dump a heavy stick table on the CLI with a screen scrolling. No backport is needed since this was introduced in 3.0-dev3 and revealed after dev5 only. --- src/applet.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/applet.c b/src/applet.c index 8e7ac445b..d1526ef89 100644 --- a/src/applet.c +++ b/src/applet.c @@ -516,7 +516,7 @@ size_t appctx_htx_rcv_buf(struct appctx *appctx, struct buffer *buf, size_t coun size_t appctx_raw_rcv_buf(struct appctx *appctx, struct buffer *buf, size_t count, unsigned int flags) { - return b_xfer(buf, &appctx->outbuf, MAX(count, b_data(&appctx->outbuf))); + return b_xfer(buf, &appctx->outbuf, MIN(count, b_data(&appctx->outbuf))); } size_t appctx_rcv_buf(struct stconn *sc, struct buffer *buf, size_t count, unsigned int flags)