Date: Wed, 28 Nov 2018 09:10:41 +0000 From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 230498] Fatal trap 12: page fault while in kernel mode in sysctl_dumpentry from sysctl NET_RT_DUMP Message-ID: <bug-230498-7501-fXuqZFIMgP@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-230498-7501@https.bugs.freebsd.org/bugzilla/> References: <bug-230498-7501@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D230498 --- Comment #21 from Andrey V. Elsukov <ae@FreeBSD.org> --- (In reply to Franck Rousseau from comment #20) > (In reply to commit-hook from comment #19) >=20 > As mentioned in comment #9 above, this patch breaks ppp, I get this when > trying to re-open a second connection, this is the stage at which the cra= sh > occured before: > PPp ON localhost> Warning: iface add: ioctl(SIOCAIFADDR, 192.168.0.2 = -> > 192.168.0.1): File exists > Error: ipcp_InterfaceUp: unable to set ip address >=20 > Also, the patch in attachment #199450 [details] does not fix this specific > problem, we still crash the kernel with the procedure described earlier in > comment #12. As I said, I could narrow down the cause and find a fix for = our > use case, by using two different IPv4 addresses for Ethernet and PPP tun > interfaces the kernel does not crash anymore. >=20 > About the fix, I suspect that internal structures are corrupted, so any k= ind > of fix at this point will fail, for example with this patch on 11.2-p4 it > looks like I keep getting these values after the crash: >=20 > (kgdb) print rt->rt_ifp->if_flags > $3 =3D 3 > (kgdb) print rt->rt_ifp->if_index > $4 =3D 63488 >=20 > I will try to setup on-line debugging to watch internal structures and see > if I can get an idea of what is breaking things up. According to if_flags this patch doesn't affect your case, since if_flags = =3D (IFF_UP | IFF_BROADCAST). There is no IFF_DYING flag. Also, rtsock has seve= ral places where it can panic due to the similar issue, but with different stack trace (for example https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D205= 678). Are you sure that your panic is the same? Also if_index has unusual very la= rge value. Pleas, show your backtrace and show in context of noted frame the ou= tput of "p *rt->rt_ifp" command. --=20 You are receiving this mail because: You are the assignee for the bug.=
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