WITNESS backtraces?

Are these messages something the list has any interest in or should I
pay no attention to them?

malloc(M_WAITOK) of "16", forcing M_NOWAIT with the following
non-sleepable locks held:
exclusive sleep mutex ath0 (network driver) r = 0 (0xc1682cc4) locked _at_
/usr/src/sys/modules/ath/../../dev/ath/if_ath.c:4672
KDB: stack backtrace:
kdb_backtrace(1,0,c0c4d540,0,dd144b04) at kdb_backtrace+0x29
witness_warn(5,0,c0608e6b,c05e923d,0) at witness_warn+0x18e
uma_zalloc_arg(c0c4d540,0,2) at uma_zalloc_arg+0x41
malloc(0,c0624b20,2,801c69ea,c167348c) at malloc+0xae
ieee80211_ioctl_setoptie(c16821ac,c18294c0,dd144b64,246,c064e600) at
ieee80211_ioctl_setoptie+0x38
ieee80211_ioctl_set80211(c16821ac,801c69ea,c18294c0,0,801c69ea) at
ieee80211_ioctl_set80211+0x6bb
ieee80211_ioctl(c16821ac,801c69ea,c18294c0,c1682cc4,6af) at
ieee80211_ioctl+0x105
ath_ioctl(c1660800,801c69ea,c18294c0,dd144c40,c04b5f80) at
ath_ioctl+0xb4
in_control(c17e7914,801c69ea,c18294c0,c1660800,c1779a80) at
in_control+0xb33
ifioctl(c17e7914,801c69ea,c18294c0,c1779a80,0) at ifioctl+0x187
soo_ioctl(c1798900,801c69ea,c18294c0,c179be80,c1779a80) at
soo_ioctl+0x2db
ioctl(c1779a80,dd144d04,3,3,282) at ioctl+0x370
syscall(3b,3b,3b,bfbfdf7c,8063160) at syscall+0x22f
Xint0x80_syscall() at Xint0x80_syscall+0x1f
--- syscall (54, FreeBSD ELF32, ioctl), eip = 0x280f21db, esp =
0xbfbfdf3c, ebp = 0xbfbfdf98 ---


-Snow