DF-4939 / run.log
DF-4939 run.log — full transcript of the decisive runs (guest ssh, root)
=========================================================================
[setup: load virtual i2c stack — see build.log for harness compile]
# kldload /root/harness/lpbbfake.ko && kldload iicbb && kldload iicbus && kldload if_ic
kldload: can't load iicbus: module already loaded or in kernel
(auto-loaded as MODULE_DEPEND of iicbb; if_ic auto-loaded by newbus
child name resolution — dmesg below)
# kldstat | grep -E "lpbb|iic|ic"
5 1 0xffffffff82600000 15000 if_ic.ko
6 2 0xffffffff82615000 1f000 iicbus.ko
7 1 0xffffffff82634000 1000 lpbbfake.ko
8 1 0xffffffff82635000 18000 iicbb.ko
# dmesg | grep -iE "^(ic|lpbb|iic)"
lpbb0: <virtual I2C bit-bang bridge (lpbbfake)> on isa0
lpbb1: <virtual I2C bit-bang bridge (lpbbfake)> on isa1
iicbb0: <I2C bit-banging driver> on lpbb0
iicbus0: <Philips I2C bus> on iicbb0 addr 0xff
ic0 on iicbus0
iicbb1: <I2C bit-banging driver> on lpbb1
iicbus1: <Philips I2C bus> on iicbb1 addr 0xff
ic1 on iicbus1
[configure — NOTE: ic is IFF_POINTOPOINT, dest addr required]
# ifconfig ic0 10.99.99.1 10.99.99.2 netmask 255.255.255.252 up
# ifconfig ic0 | head -1
ic0: flags=808851<UP,POINTOPOINT,RUNNING,SIMPLEX,MULTICAST,PROXY> metric 0 mtu 1500
[baseline]
# vmstat -m | grep -i devbuf
devbuf 219 214K 0 390M 232
[200 down/up cycles — UNFIXED kernel]
# i=0; while [ $i -lt 200 ]; do ifconfig ic0 down; ifconfig ic0 up; i=$((i+1)); done; echo CYCLES-DONE
CYCLES-DONE
# vmstat -m | grep -i devbuf
devbuf 619 814K 0 390M 632
-> +400 allocations / +600K == 2 x (1500+4) B leaked per cycle
[+100 more cycles — determinism check]
# i=0; while [ $i -lt 100 ]; do ifconfig ic0 down; ifconfig ic0 up; i=$((i+1)); done
# vmstat -m | grep -i devbuf
devbuf 819 1.09M 0 390M 832
-> +200 allocations / +300K (300/300 cycles leaked; deterministic)
=========================================================================
FIX VALIDATION (patched if_ic.ko built from fix.diff applied to guest
/usr/src copy — build.log.fix; rebooted into patched module)
=========================================================================
# ifconfig ic0 10.99.99.1 10.99.99.2 netmask 255.255.255.252 up
ic0: flags=808851<UP,POINTOPOINT,RUNNING,SIMPLEX,MULTICAST,PROXY> metric 0 mtu 1500
# vmstat -m | grep -i devbuf
devbuf 219 214K 0 390M 232
# i=0; while [ $i -lt 200 ]; do ifconfig ic0 down; ifconfig ic0 up; i=$((i+1)); done; echo FIX-CYCLES-DONE
FIX-CYCLES-DONE
# vmstat -m | grep -i devbuf
devbuf 219 214K 0 390M 232
-> BYTE-FLAT across the same 200 cycles: leak eliminated (baseline
unfixed run: +400 allocs / +600K). Bad behavior GONE on patched module.