caif: reduce stack size with KASAN

BugLink: https://bugs.launchpad.net/bugs/1838459
commit ce6289661b14a8b391d90db918c91b6d6da6540a upstream.

When CONFIG_KASAN is set, we can use relatively large amounts of kernel
stack space:

net/caif/cfctrl.c:555:1: warning: the frame size of 1600 bytes is larger than 1280 bytes [-Wframe-larger-than=]

This adds convenience wrappers around cfpkt_extr_head(), which is responsible
for most of the stack growth. With those wrapper functions, gcc apparently
starts reusing the stack slots for each instance, thus avoiding the
problem.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/include/net/caif/cfpkt.h b/include/net/caif/cfpkt.h
index fe328c52c46bd179b651d6bbb14e58a89f017557..801489bb14c3437d3419a6dd00766787b6fce100 100644 (file)
--- a/include/net/caif/cfpkt.h
+++ b/include/net/caif/cfpkt.h
@@ -32,6 +32,33 @@ void cfpkt_destroy(struct cfpkt *pkt);
  */
 int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len);
 
+static inline u8 cfpkt_extr_head_u8(struct cfpkt *pkt)
+{
+       u8 tmp;
+
+       cfpkt_extr_head(pkt, &tmp, 1);
+
+       return tmp;
+}
+
+static inline u16 cfpkt_extr_head_u16(struct cfpkt *pkt)
+{
+       __le16 tmp;
+
+       cfpkt_extr_head(pkt, &tmp, 2);
+
+       return le16_to_cpu(tmp);
+}
+
+static inline u32 cfpkt_extr_head_u32(struct cfpkt *pkt)
+{
+       __le32 tmp;
+
+       cfpkt_extr_head(pkt, &tmp, 4);
+
+       return le32_to_cpu(tmp);
+}
+
 /*
  * Peek header from packet.
  * Reads data from packet without changing packet.

diff --git a/net/caif/cfctrl.c b/net/caif/cfctrl.c
index 655ed7032150309062d0c8c85cda571d34030423..a1e85f0321081cfd305f3428dc6bdb155aebc40a 100644 (file)
--- a/net/caif/cfctrl.c
+++ b/net/caif/cfctrl.c
@@ -352,15 +352,14 @@ static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
        u8 cmdrsp;
        u8 cmd;
        int ret = -1;
-       u16 tmp16;
        u8 len;
        u8 param[255];
-       u8 linkid;
+       u8 linkid = 0;
        struct cfctrl *cfctrl = container_obj(layer);
        struct cfctrl_request_info rsp, *req;
 
 
-       cfpkt_extr_head(pkt, &cmdrsp, 1);
+       cmdrsp = cfpkt_extr_head_u8(pkt);
        cmd = cmdrsp & CFCTRL_CMD_MASK;
        if (cmd != CFCTRL_CMD_LINK_ERR
            && CFCTRL_RSP_BIT != (CFCTRL_RSP_BIT & cmdrsp)
@@ -378,13 +377,12 @@ static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
                        u8 physlinkid;
                        u8 prio;
                        u8 tmp;
-                       u32 tmp32;
                        u8 *cp;
                        int i;
                        struct cfctrl_link_param linkparam;
                        memset(&linkparam, 0, sizeof(linkparam));
 
-                       cfpkt_extr_head(pkt, &tmp, 1);
+                       tmp = cfpkt_extr_head_u8(pkt);
 
                        serv = tmp & CFCTRL_SRV_MASK;
                        linkparam.linktype = serv;
@@ -392,13 +390,13 @@ static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
                        servtype = tmp >> 4;
                        linkparam.chtype = servtype;
 
-                       cfpkt_extr_head(pkt, &tmp, 1);
+                       tmp = cfpkt_extr_head_u8(pkt);
                        physlinkid = tmp & 0x07;
                        prio = tmp >> 3;
 
                        linkparam.priority = prio;
                        linkparam.phyid = physlinkid;
-                       cfpkt_extr_head(pkt, &endpoint, 1);
+                       endpoint = cfpkt_extr_head_u8(pkt);
                        linkparam.endpoint = endpoint & 0x03;
 
                        switch (serv) {
@@ -407,45 +405,43 @@ static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
                                if (CFCTRL_ERR_BIT & cmdrsp)
                                        break;
                                /* Link ID */
-                               cfpkt_extr_head(pkt, &linkid, 1);
+                               linkid = cfpkt_extr_head_u8(pkt);
                                break;
                        case CFCTRL_SRV_VIDEO:
-                               cfpkt_extr_head(pkt, &tmp, 1);
+                               tmp = cfpkt_extr_head_u8(pkt);
                                linkparam.u.video.connid = tmp;
                                if (CFCTRL_ERR_BIT & cmdrsp)
                                        break;
                                /* Link ID */
-                               cfpkt_extr_head(pkt, &linkid, 1);
+                               linkid = cfpkt_extr_head_u8(pkt);
                                break;
 
                        case CFCTRL_SRV_DATAGRAM:
-                               cfpkt_extr_head(pkt, &tmp32, 4);
                                linkparam.u.datagram.connid =
-                                   le32_to_cpu(tmp32);
+                                   cfpkt_extr_head_u32(pkt);
                                if (CFCTRL_ERR_BIT & cmdrsp)
                                        break;
                                /* Link ID */
-                               cfpkt_extr_head(pkt, &linkid, 1);
+                               linkid = cfpkt_extr_head_u8(pkt);
                                break;
                        case CFCTRL_SRV_RFM:
                                /* Construct a frame, convert
                                 * DatagramConnectionID
                                 * to network format long and copy it out...
                                 */
-                               cfpkt_extr_head(pkt, &tmp32, 4);
                                linkparam.u.rfm.connid =
-                                 le32_to_cpu(tmp32);
+                                   cfpkt_extr_head_u32(pkt);
                                cp = (u8 *) linkparam.u.rfm.volume;
-                               for (cfpkt_extr_head(pkt, &tmp, 1);
+                               for (tmp = cfpkt_extr_head_u8(pkt);
                                     cfpkt_more(pkt) && tmp != '\0';
-                                    cfpkt_extr_head(pkt, &tmp, 1))
+                                    tmp = cfpkt_extr_head_u8(pkt))
                                        *cp++ = tmp;
                                *cp = '\0';
 
                                if (CFCTRL_ERR_BIT & cmdrsp)
                                        break;
                                /* Link ID */
-                               cfpkt_extr_head(pkt, &linkid, 1);
+                               linkid = cfpkt_extr_head_u8(pkt);
 
                                break;
                        case CFCTRL_SRV_UTIL:
@@ -454,13 +450,11 @@ static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
                                 * to network format long and copy it out...
                                 */
                                /* Fifosize KB */
-                               cfpkt_extr_head(pkt, &tmp16, 2);
                                linkparam.u.utility.fifosize_kb =
-                                   le16_to_cpu(tmp16);
+                                   cfpkt_extr_head_u16(pkt);
                                /* Fifosize bufs */
-                               cfpkt_extr_head(pkt, &tmp16, 2);
                                linkparam.u.utility.fifosize_bufs =
-                                   le16_to_cpu(tmp16);
+                                   cfpkt_extr_head_u16(pkt);
                                /* name */
                                cp = (u8 *) linkparam.u.utility.name;
                                caif_assert(sizeof(linkparam.u.utility.name)
@@ -468,24 +462,24 @@ static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
                                for (i = 0;
                                     i < UTILITY_NAME_LENGTH
                                     && cfpkt_more(pkt); i++) {
-                                       cfpkt_extr_head(pkt, &tmp, 1);
+                                       tmp = cfpkt_extr_head_u8(pkt);
                                        *cp++ = tmp;
                                }
                                /* Length */
-                               cfpkt_extr_head(pkt, &len, 1);
+                               len = cfpkt_extr_head_u8(pkt);
                                linkparam.u.utility.paramlen = len;
                                /* Param Data */
                                cp = linkparam.u.utility.params;
                                while (cfpkt_more(pkt) && len--) {
-                                       cfpkt_extr_head(pkt, &tmp, 1);
+                                       tmp = cfpkt_extr_head_u8(pkt);
                                        *cp++ = tmp;
                                }
                                if (CFCTRL_ERR_BIT & cmdrsp)
                                        break;
                                /* Link ID */
-                               cfpkt_extr_head(pkt, &linkid, 1);
+                               linkid = cfpkt_extr_head_u8(pkt);
                                /* Length */
-                               cfpkt_extr_head(pkt, &len, 1);
+                               len = cfpkt_extr_head_u8(pkt);
                                /* Param Data */
                                cfpkt_extr_head(pkt, &param, len);
                                break;
@@ -522,7 +516,7 @@ static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
                }
                break;
        case CFCTRL_CMD_LINK_DESTROY:
-               cfpkt_extr_head(pkt, &linkid, 1);
+               linkid = cfpkt_extr_head_u8(pkt);
                cfctrl->res.linkdestroy_rsp(cfctrl->serv.layer.up, linkid);
                break;
        case CFCTRL_CMD_LINK_ERR: