Date: Tue, 21 Jun 2005 13:07:01 +0400 From: Gleb Smirnoff <glebius@FreeBSD.org> To: Jeremie Le Hen <jeremie@le-hen.org> Cc: freebsd-stable@FreeBSD.org Subject: Re: panic in RELENG_5 UMA Message-ID: <20050621090701.GB34406@cell.sick.ru> In-Reply-To: <20050621070427.GA738@obiwan.tataz.chchile.org> References: <20050621070427.GA738@obiwan.tataz.chchile.org>
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On Tue, Jun 21, 2005 at 09:04:27AM +0200, Jeremie Le Hen wrote:
J> #25 0xc05a0a0b in m_freem (mb=0x0) at uma.h:304
J> No locals.
J> #26 0xc05ee0d5 in arpresolve (ifp=0xc1a5b000, rt0=0xc1d44000, m=0xc1be7200,
J> dst=0xd6d3fa94, desten=0xd6d3fa2c "/??]??????w??")
J> at ../../../netinet/if_ether.c:442
J> la = (struct llinfo_arp *) 0xc1a75a00
J> sdl = (struct sockaddr_dl *) 0xc2128910
J> error = -1038972656
J> rt = (struct rtentry *) 0xc1d44000
IMHO, this looks like a race. The route is not locked, when
its llinfo is edited.
Probably the mbuf was freed when arp reply arrived and la_hold was send.
Look into in_arpinput() near 736:
(*ifp->if_output)(ifp, la->la_hold, rt_key(rt), rt);
la->la_hold = 0;
Yeah, I have just triggered another panic running 15 instances of this script on
SMP box:
(
while (true); do
arp -d 81.19.64.111 >/dev/null 2>&1;
ping -c 1 -t 1 81.19.64.111 >/dev/null 2>&1;
done
) &
But my duplicate free is in fxp_txeof(). This means that output thread has
won the race.
--
Totus tuus, Glebius.
GLEBIUS-RIPN GLEB-RIPE
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