Date: Thu, 3 Mar 2005 15:28:18 -0500 From: John Baldwin <jhb@FreeBSD.org> To: Bill Paul <wpaul@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/net80211 ieee80211_ioctl.c Message-ID: <200503031528.18834.jhb@FreeBSD.org> In-Reply-To: <200503031735.j23HZ5hv094849@repoman.freebsd.org> References: <200503031735.j23HZ5hv094849@repoman.freebsd.org>
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On Thursday 03 March 2005 12:35 pm, Bill Paul wrote: > wpaul 2005-03-03 17:35:05 UTC > > FreeBSD src repository > > Modified files: > sys/net80211 ieee80211_ioctl.c > Log: > Recently, it was reported to me that you could provoke a double fault > panic with the NDISulator if you did "ifconfig ndis0 10.0.0.1/24," > whereas "ifconfig ndis0 10.0.0.1/24 up" worked fine. The double fault > was caused by the ifconfig thread running out of kernel stack space. > (This was partly due to the NDIsulator using a couple of big buffers on > the stack, but even after fixing that the double fault persisted.) > > It turns out that ndis_init() is called in both cases, but in the first > case the code path passes through ieee80211_ioctl(), and it turns out > ieee80211_ioctl() consumes a whopping 2400 bytes of stack space. > Apparently, gcc -O2 causes the ieee80211_ioctl_get80211() routine to > be inlined into ieee80211_ioctl(), and for some reason which I do not > fully understand, this causes ieee80211_ioctl() to consume an extra 2K > of stack space. > > To prevent this overly agressive optimization, ieee80211_ioctl_get80211() > is now declared with __attribute__ ((noinline)). With this change, > ieee80211_ioctl() now only reserves about 200 bytes of stack instead of > 2400. Hmm, this might fix the double fault panics with wlan_wep.ko when WITNESS is enabled as well. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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