Date: Sun, 9 Aug 2015 22:18:20 -0400 From: Patrick Kelsey <pkelsey@freebsd.org> To: Gleb Smirnoff <glebius@freebsd.org> Cc: Kristof Provost <kp@freebsd.org>, freebsd-current <freebsd-current@freebsd.org> Subject: Re: sysctl -a panic on VIMAGE kernels Message-ID: <CAD44qMXko_0FSFdj1xuhL4hyfU1SNv3nVs-DCMc6x8LCN7nMZw@mail.gmail.com> In-Reply-To: <20150809103635.GA889@glebius.int.ru> References: <B09833EB-ABE0-44BF-A53A-554207B92637@FreeBSD.org> <20150809103635.GA889@glebius.int.ru>
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On Sun, Aug 9, 2015 at 6:36 AM, Gleb Smirnoff <glebius@freebsd.org> wrote: > On Sun, Aug 09, 2015 at 12:28:22PM +0200, Kristof Provost wrote: > K> Hi, > K> > K> I=E2=80=99ve run into a reproducible panic on a VIMAGE kernel with =E2= =80=98sysctl -a=E2=80=99. > K> > K> Relevant backtrace bits: > K> #8 0xffffffff80e7dd28 in trap (frame=3D0xfffffe01f16b26a0) > K> at /usr/src/sys/amd64/amd64/trap.c:426 > K> #9 0xffffffff80e5e6a2 in calltrap () > K> at /usr/src/sys/amd64/amd64/exception.S:235 > K> #10 0xffffffff80cea67d in uma_zone_get_cur (zone=3D0x0) > K> at /usr/src/sys/vm/uma_core.c:3006 > K> #11 0xffffffff80cec029 in sysctl_handle_uma_zone_cur ( > K> oidp=3D0xffffffff818a7c90, arg1=3D0xfffffe00010c0438, arg2=3D0, > K> req=3D0xfffffe01f16b2868) at /usr/src/sys/vm/uma_core.c:3580 > K> #12 0xffffffff80a28614 in sysctl_root_handler_locked > (oid=3D0xffffffff818a7c90, > K> arg1=3D0xfffffe00010c0438, arg2=3D0, req=3D0xfffffe01f16b2868) > K> at /usr/src/sys/kern/kern_sysctl.c:183 > K> #13 0xffffffff80a27d70 in sysctl_root (arg1=3D<value optimized out>, > K> arg2=3D<value optimized out>) at /usr/src/sys/kern/kern_sysctl.c:1= 694 > K> #14 0xffffffff80a28372 in userland_sysctl (td=3D0x0, > name=3D0xfffffe01f16b2930, > K> namelen=3D<value optimized out>, old=3D<value optimized out>, > K> oldlenp=3D<value optimized out>, inkernel=3D<value optimized out>, > K> new=3D<value optimized out>, newlen=3D<value optimized out>, > K> retval=3D<value optimized out>, flags=3D0) > K> at /usr/src/sys/kern/kern_sysctl.c:1798 > K> #15 0xffffffff80a28144 in sys___sysctl (td=3D0xfffff8000b1e49a0, > K> uap=3D0xfffffe01f16b2a40) at /usr/src/sys/kern/kern_sysctl.c:1724 > K> > K> In essence, what happens is that we end up in > sysctl_handle_uma_zone_cur() and arg1 is a pointer to NULL, > K> so we call uma_zone_get_cur(zone); with zone =3D=3D NULL. > K> > K> There=E2=80=99s been a bit of churn around tcp_reass_zone, and I think= the > latest version is wrong. > K> It marks the sysctl as CTLFLAG_VNET, but the exposed variable is not > VNET_DEFINE(). > K> > K> The following fixes it for me: > K> > K> diff --git a/sys/netinet/tcp_reass.c b/sys/netinet/tcp_reass.c > K> index 77d8940..3913ef3 100644 > K> --- a/sys/netinet/tcp_reass.c > K> +++ b/sys/netinet/tcp_reass.c > K> @@ -84,7 +84,7 @@ SYSCTL_INT(_net_inet_tcp_reass, OID_AUTO, > maxsegments, CTLFLAG_RDTUN, > K> "Global maximum number of TCP Segments in Reassembly Queue"); > K> > K> static uma_zone_t tcp_reass_zone; > K> -SYSCTL_UMA_CUR(_net_inet_tcp_reass, OID_AUTO, cursegments, > CTLFLAG_VNET, > K> +SYSCTL_UMA_CUR(_net_inet_tcp_reass, OID_AUTO, cursegments, 0, > K> &tcp_reass_zone, > K> "Global number of TCP Segments currently in Reassembly Queue=E2= =80=9D); > > Right, if a variable isn't virtualized, the CTLFLAG_VNET must be removed. > > Patrick, how is your progress wuth improved reassembly? > Kristof, thanks for committing this patch. Gleb, I expect to have a tcp reassembly patch up for review at some point this week. -Patrick
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