diff --git a/include/haproxy/channel.h b/include/haproxy/channel.h
index 0c872dc31..af2989416 100644
--- a/include/haproxy/channel.h
+++ b/include/haproxy/channel.h
@@ -787,8 +787,12 @@ static inline int channel_recv_max(const struct channel *chn)
  */
 static inline size_t channel_data_limit(const struct channel *chn)
 {
-	size_t max = (global.tune.bufsize - global.tune.maxrewrite);
 
+	size_t max;
+
+	if (!c_size(chn))
+		return 0;
+	max = (c_size(chn) - global.tune.maxrewrite);
 	if (IS_HTX_STRM(chn_strm(chn)))
 		max -= HTX_BUF_OVERHEAD;
 	return max;
diff --git a/include/haproxy/proxy-t.h b/include/haproxy/proxy-t.h
index 20c359126..5f58bdb4c 100644
--- a/include/haproxy/proxy-t.h
+++ b/include/haproxy/proxy-t.h
@@ -293,7 +293,8 @@ struct error_snapshot {
 	struct server *srv;             /* server associated with the error (or NULL) */
 	/* @64 */
 	unsigned int ev_id;             /* event number (counter incremented for each capture) */
-	/* @68: 4 bytes hole here */
+	unsigned int buf_size;          /* buffer size */
+
 	struct sockaddr_storage src;    /* client's address */
 
 	/**** protocol-specific part ****/
diff --git a/include/haproxy/sc_strm.h b/include/haproxy/sc_strm.h
index 5d473f3b8..bac877dc1 100644
--- a/include/haproxy/sc_strm.h
+++ b/include/haproxy/sc_strm.h
@@ -133,7 +133,7 @@ static inline void sc_have_room(struct stconn *sc)
 static inline void sc_need_room(struct stconn *sc, ssize_t room_needed)
 {
 	sc->flags |= SC_FL_NEED_ROOM;
-	BUG_ON_HOT(room_needed > (ssize_t)global.tune.bufsize);
+	BUG_ON_HOT(room_needed > (ssize_t)c_size(sc_ic(sc)));
 	sc->room_needed = room_needed;
 }
 
diff --git a/src/hlua.c b/src/hlua.c
index b826e6ab8..34b93b036 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -3952,7 +3952,7 @@ __LJMP static int hlua_channel_get_data_yield(lua_State *L, int status, lua_KCon
 		if (!len)
 			goto dup;
 		if (len == -1)
-			len = global.tune.bufsize;
+			len = c_size(chn);
 		if (len < 0) {
 			lua_pushfstring(L, "length out of range.");
 			WILL_LJMP(lua_error(L));
@@ -4035,7 +4035,7 @@ __LJMP static int hlua_channel_get_line_yield(lua_State *L, int status, lua_KCon
 		if (!len)
 			goto dup;
 		if (len == -1)
-			len = global.tune.bufsize;
+			len = c_size(chn);
 		if (len < 0) {
 			lua_pushfstring(L, "length out of range.");
 			WILL_LJMP(lua_error(L));
@@ -7470,7 +7470,7 @@ __LJMP static int hlua_http_msg_get_body(lua_State *L)
 		if (!len)
 			goto dup;
 		if (len == -1)
-			len = global.tune.bufsize;
+			len = c_size(msg->chn);
 		if (len < 0) {
 			lua_pushfstring(L, "length out of range.");
 			WILL_LJMP(lua_error(L));
diff --git a/src/http_fetch.c b/src/http_fetch.c
index b8b6f616c..1f8ff8c99 100644
--- a/src/http_fetch.c
+++ b/src/http_fetch.c
@@ -138,7 +138,7 @@ static int get_http_auth(struct sample *smp, struct htx *htx)
 
 		len = base64dec(txn->auth.method_data.area,
 				txn->auth.method_data.data,
-				http_auth->area, global.tune.bufsize - 1);
+				http_auth->area, http_auth->size -1);
 
 		if (len < 0)
 			return 0;
diff --git a/src/mux_h1.c b/src/mux_h1.c
index 81bd071ba..045fd603a 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -4008,8 +4008,8 @@ static int h1_recv(struct h1c *h1c)
 		 * a pointer swap and the next read will be doable at once in
 		 * an empty buffer.
 		 */
-		if (max > global.tune.bufsize - global.tune.maxrewrite)
-			max = global.tune.bufsize - global.tune.maxrewrite;
+		if (max > b_size(&h1c->ibuf) - global.tune.maxrewrite)
+			max = b_size(&h1c->ibuf) - global.tune.maxrewrite;
 	}
 
 	if (max) {
diff --git a/src/mux_h2.c b/src/mux_h2.c
index a870426dc..41fbbc26d 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -4256,7 +4256,7 @@ static void h2_process_demux(struct h2c *h2c)
 				goto done;
 			}
 
-			if ((int)hdr.len < 0 || (int)hdr.len > global.tune.bufsize) {
+			if ((int)hdr.len < 0 || (int)hdr.len > b_size(&h2c->dbuf)) {
 				/* RFC7540#3.5: a GOAWAY frame MAY be omitted */
 				h2c_report_glitch(h2c, 1, "invalid settings frame length");
 				TRACE_ERROR("invalid settings frame length", H2_EV_RX_FRAME|H2_EV_RX_FHDR|H2_EV_RX_SETTINGS|H2_EV_PROTO_ERR, h2c->conn);
@@ -4303,7 +4303,7 @@ static void h2_process_demux(struct h2c *h2c)
 				break;
 			}
 
-			if ((int)hdr.len < 0 || (int)hdr.len > global.tune.bufsize) {
+			if ((int)hdr.len < 0 || (int)hdr.len > b_size(&h2c->dbuf)) {
 				h2c_report_glitch(h2c, 1, "invalid H2 frame length");
 				TRACE_ERROR("invalid H2 frame length", H2_EV_RX_FRAME|H2_EV_RX_FHDR|H2_EV_PROTO_ERR, h2c->conn);
 				h2c_error(h2c, H2_ERR_FRAME_SIZE_ERROR);
@@ -4384,7 +4384,7 @@ static void h2_process_demux(struct h2c *h2c)
 			h2c->st0 = H2_CS_FRAME_P;
 
 			/* check for minimum basic frame format validity */
-			ret = h2_frame_check(h2c->dft, 1, h2c->dsi, h2c->dfl, global.tune.bufsize);
+			ret = h2_frame_check(h2c->dft, 1, h2c->dsi, h2c->dfl, b_size(&h2c->dbuf));
 			if (ret != H2_ERR_NO_ERROR) {
 				h2c_report_glitch(h2c, 1, "received invalid H2 frame header");
 				TRACE_ERROR("received invalid H2 frame header", H2_EV_RX_FRAME|H2_EV_RX_FHDR|H2_EV_PROTO_ERR, h2c->conn);
@@ -6066,7 +6066,7 @@ next_frame:
 			goto fail;
 		}
 
-		if ((unsigned)hdr.len > (unsigned)global.tune.bufsize) {
+		if ((unsigned)hdr.len > (unsigned)b_size(&h2c->dbuf)) {
 			/* RFC7540#4.2: invalid frame length */
 			h2c_report_glitch(h2c, 1, "too large CONTINUATION frame");
 			TRACE_STATE("too large CONTINUATION frame", H2_EV_RX_FRAME|H2_EV_RX_FHDR|H2_EV_RX_HDR|H2_EV_RX_CONT|H2_EV_H2C_ERR|H2_EV_PROTO_ERR, h2c->conn);
diff --git a/src/payload.c b/src/payload.c
index 62071aca6..e1a158355 100644
--- a/src/payload.c
+++ b/src/payload.c
@@ -1205,7 +1205,6 @@ smp_fetch_payload_lv(const struct arg *arg_p, struct sample *smp, const char *kw
 	unsigned int len_size = arg_p[1].data.sint;
 	unsigned int buf_offset;
 	unsigned int buf_size = 0;
-	struct channel *chn = NULL;
 	char *head = NULL;
 	size_t max, data;
 	int i;
@@ -1215,12 +1214,15 @@ smp_fetch_payload_lv(const struct arg *arg_p, struct sample *smp, const char *kw
 	/* buf offset could be absolute or relative to len offset + len size if prefixed by + or - */
 
 	if (smp->strm) {
+		struct channel *chn = NULL;
+
 		/* meaningless for HTX buffers */
 		if (IS_HTX_STRM(smp->strm))
 			return 0;
 		chn = ((smp->opt & SMP_OPT_DIR) == SMP_OPT_DIR_RES) ? &smp->strm->res : &smp->strm->req;
 		head = ci_head(chn);
 		data = ci_data(chn);
+		max = c_size(chn);
 	}
 	else if (obj_type(smp->sess->origin) == OBJ_TYPE_CHECK) {
 		struct check *check = __objt_check(smp->sess->origin);
@@ -1230,8 +1232,9 @@ smp_fetch_payload_lv(const struct arg *arg_p, struct sample *smp, const char *kw
 			return 0;
 		head = b_head(&check->bi);
 		data = b_data(&check->bi);
+		max = b_size(&check->bi);
 	}
-	max = global.tune.bufsize;
+
 	if (!head)
 		goto too_short;
 
@@ -1290,6 +1293,7 @@ smp_fetch_payload(const struct arg *arg_p, struct sample *smp, const char *kw, v
 		chn = ((smp->opt & SMP_OPT_DIR) == SMP_OPT_DIR_RES) ? &smp->strm->res : &smp->strm->req;
 		head = ci_head(chn);
 		data = ci_data(chn);
+		max = c_size(chn);
 	}
 	else if (obj_type(smp->sess->origin) == OBJ_TYPE_CHECK) {
 		struct check *check = __objt_check(smp->sess->origin);
@@ -1299,8 +1303,8 @@ smp_fetch_payload(const struct arg *arg_p, struct sample *smp, const char *kw, v
 			return 0;
 		head = b_head(&check->bi);
 		data = b_data(&check->bi);
+		max =  b_size(&check->bi);
 	}
-	max = global.tune.bufsize;
 	if (!head)
 		goto too_short;
 
diff --git a/src/proxy.c b/src/proxy.c
index 06c3fb877..778c9d9e4 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -4173,6 +4173,7 @@ void proxy_capture_error(struct proxy *proxy, int is_back,
 	if (!es)
 		return;
 
+	es->buf_size = buf->size;
 	es->buf_len = buf_len;
 	es->ev_id   = ev_id;
 
@@ -5224,7 +5225,7 @@ static int cli_io_handler_show_errors(struct appctx *appctx)
 			              es->srv ? es->srv->puid : -1,
 			              es->ev_id, pn, port,
 			              es->buf_ofs, es->buf_out,
-			              global.tune.bufsize - es->buf_out - es->buf_len,
+			              es->buf_size - es->buf_out - es->buf_len,
 			              es->buf_len, es->buf_wrap, es->buf_err);
 
 			if (es->show)
@@ -5250,12 +5251,12 @@ static int cli_io_handler_show_errors(struct appctx *appctx)
 		}
 
 		/* OK, ptr >= 0, so we have to dump the current line */
-		while (ctx->ptr < es->buf_len && ctx->ptr < global.tune.bufsize) {
+		while (ctx->ptr < es->buf_len && ctx->ptr < es->buf_size) {
 			int newptr;
 			int newline;
 
 			newline = ctx->bol;
-			newptr = dump_text_line(&trash, es->buf, global.tune.bufsize, es->buf_len, &newline, ctx->ptr);
+			newptr = dump_text_line(&trash, es->buf, es->buf_size, es->buf_len, &newline, ctx->ptr);
 			if (newptr == ctx->ptr) {
 				applet_fl_set(appctx, APPCTX_FL_OUTBLK_FULL);
 				goto cant_send_unlock;
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index a7323426c..291aa9467 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -5918,7 +5918,7 @@ static int ssl_sock_init(struct connection *conn, void **xprt_ctx)
 			     * a buffer.
 			     */
 			    (!b_is_null(&ctx->early_buf)) ?
-			    global.tune.bufsize - global.tune.maxrewrite : 0);
+			    ctx->early_buf.size - global.tune.maxrewrite : 0);
 		}
 #endif