>Synopsis: tsec(4) tx hangs, flagged OACTIVE
>Category: kernel
>Environment:
System : OpenBSD 5.8
Details : OpenBSD 5.8-current (GENERIC) #105: Mon Sep 7 08:21:16
MDT 2015
[email protected]:/usr/src/sys/arch/socppc/compile/GENERIC
Architecture: OpenBSD.socppc
Machine : socppc
>Description:
After at most 15 minutes or so of the loop below the interface tx
goes out to lunch and never returns. ifconfig shows it is
flagged OACTIVE. The watchdog timeout never appears in dmesg.
tcpdump sees rx but no tx.
>How-To-Repeat:
# while true; do ls -lR /; done
>Fix:
# ifconfig tsec${x} down && ifconfig tsec${x} up
The hang looks due to IFF_OACTIVE being set on error return
from tsec_encap():
if_tsec.c: tsec_start()
534 if (tsec_encap(sc, m, &idx)) {
535 ifp->if_flags |= IFF_OACTIVE;
536 break;
537 }
Although the flag is unset by tsec_tx_proc() this won't occur if
there are no pending tx (nor will the watchdog be running). Progess
therefore halts as tsec_start() returns immediately on IFF_OACTIVE.
The root problem is the driver cannot process an arbitrary number of
mbuf fragments as they must be mapped for DMA, and these DMA maps are
statically allocated. tsec_start() then mistakes that error return
and halts tx processing.
This is problem exists in other drivers but is masked by their
higher upper limit on mbuf fragments. e.g. vge(4), and also
sis(4), em(4) but only as a theoretical concern.
Two alternative fixes appear below. The first assumes the stack
in practice issues fewer than 32 fragments. The second doesn't.
Both tested on RB600A.
best,
Richard.
Index: if_tsec.c
===================================================================
RCS file: /cvs/src/sys/arch/socppc/dev/if_tsec.c,v
retrieving revision 1.38
diff -u -p -u -r1.38 if_tsec.c
--- if_tsec.c 25 Oct 2015 13:22:09 -0000 1.38
+++ if_tsec.c 1 Nov 2015 20:46:41 -0000
@@ -227,7 +227,7 @@ struct tsec_buf {
};
#define TSEC_NTXDESC 256
-#define TSEC_NTXSEGS 16
+#define TSEC_NTXSEGS 32
#define TSEC_NRXDESC 256
@@ -1131,8 +1131,10 @@ tsec_encap(struct tsec_softc *sc, struct
cur = frag = *idx;
map = sc->sc_txbuf[cur].tb_map;
- if (bus_dmamap_load_mbuf(sc->sc_dmat, map, m, BUS_DMA_NOWAIT))
- return (ENOBUFS);
+ if (bus_dmamap_load_mbuf(sc->sc_dmat, map, m, BUS_DMA_NOWAIT)) {
+ printf("%s: can't map mbuf\n", sc->sc_dev.dv_xname);
+ return (ENOBUFS); /* XXX tx will go out to lunch */
+ }
if (map->dm_nsegs > (TSEC_NTXDESC - sc->sc_tx_cnt - 2)) {
bus_dmamap_unload(sc->sc_dmat, map);
Index: if_tsec.c
===================================================================
RCS file: /cvs/src/sys/arch/socppc/dev/if_tsec.c,v
retrieving revision 1.38
diff -u -p -u -r1.38 if_tsec.c
--- if_tsec.c 25 Oct 2015 13:22:09 -0000 1.38
+++ if_tsec.c 1 Nov 2015 20:44:24 -0000
@@ -514,7 +514,7 @@ tsec_start(struct ifnet *ifp)
{
struct tsec_softc *sc = ifp->if_softc;
struct mbuf *m;
- int idx;
+ int error, idx;
if (!(ifp->if_flags & IFF_RUNNING))
return;
@@ -531,9 +531,16 @@ tsec_start(struct ifnet *ifp)
if (m == NULL)
break;
- if (tsec_encap(sc, m, &idx)) {
+ error = tsec_encap(sc, m, &idx);
+ if (error == ENOBUFS) {
ifp->if_flags |= IFF_OACTIVE;
break;
+ }
+ if (error == EFBIG) {
+ IFQ_DEQUEUE(&ifp->if_snd, m);
+ m_freem(m); /* give up: drop it */
+ ifp->if_oerrors++;
+ continue;
}
/* Now we are committed to transmit the packet. */
@@ -1131,8 +1138,14 @@ tsec_encap(struct tsec_softc *sc, struct
cur = frag = *idx;
map = sc->sc_txbuf[cur].tb_map;
- if (bus_dmamap_load_mbuf(sc->sc_dmat, map, m, BUS_DMA_NOWAIT))
- return (ENOBUFS);
+ if (bus_dmamap_load_mbuf(sc->sc_dmat, map, m, BUS_DMA_NOWAIT)) {
+ if (m_defrag(m, M_DONTWAIT))
+ return (EFBIG);
+ if (bus_dmamap_load_mbuf(sc->sc_dmat, map, m, BUS_DMA_NOWAIT)) {
+ printf("%s: can't map mbuf\n", sc->sc_dev.dv_xname);
+ return (EFBIG);
+ }
+ }
if (map->dm_nsegs > (TSEC_NTXDESC - sc->sc_tx_cnt - 2)) {
bus_dmamap_unload(sc->sc_dmat, map);
OpenBSD 5.8-current (GENERIC) #105: Mon Sep 7 08:21:16 MDT 2015
[email protected]:/usr/src/sys/arch/socppc/compile/GENERIC
real mem = 134217728 (128MB)
avail mem = 123711488 (117MB)
mainbus0 at root
cpu0 at mainbus0: 8347
obio0 at mainbus0
"wdt" at obio0 offset 0x00200 not configured
com0 at obio0 offset 0x04500 ivec 9: ns16550a, 16 byte fifo
com0: console
socpcic0 at obio0 offset 0x08500
pci0 at socpcic0 bus 0
"Freescale MPC8343" rev 0x30 at pci0 dev 0 function 0 not configured
vge0 at pci0 dev 11 function 0 "VIA VT612x" rev 0x11: ivec 21, address
00:0c:42:20:4e:aa
ciphy0 at vge0 phy 1: CS8201 10/100/1000TX PHY, rev. 2
ipic0 at obio0 offset 0x00700
"mdio" at obio0 offset 0x24520 not configured
tsec0 at obio0 offset 0x25000 ivec 35: address 00:0c:42:20:4e:a8
rgephy0 at tsec0 phy 0: RTL8169S/8110S/8211 PHY, rev. 2
tsec1 at obio0 offset 0x24000 ivec 32: address 00:0c:42:20:4e:a9
rgephy1 at tsec1 phy 1: RTL8169S/8110S/8211 PHY, rev. 2
"gpio" at obio0 offset 0x00c08 not configured
"beeper" at obio0 offset 0x00500 not configured
"led" at obio0 not configured
"fancon" at mainbus0 not configured
"nand" at mainbus0 not configured
"nnand" at mainbus0 not configured
"flash" at mainbus0 not configured
wdc0 at mainbus0
wd0 at wdc0 channel 0 drive 0: <SanDisk SDCFH2-4096>
wd0: 4-sector PIO, LBA, 3919MB, 8027712 sectors
wd0(wdc0:0:0): using BIOS timings
wdc1 at mainbus0
vscsi0 at root
scsibus0 at vscsi0: 256 targets
softraid0 at root
scsibus1 at softraid0: 256 targets
root on wd0a (84ccd8ef8549b483.a) swap on wd0b dump on wd0b
WARNING: unable to get date/time -- CHECK AND RESET THE DATE!
usbdevs:
usbdevs: no USB controllers found
