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Message-ID: <87k5d08t0g.fsf@natisbad.org> Date: Thu, 25 Sep 2008 11:38:39 +0200 From: arno@...isbad.org (Arnaud Ebalard) To: "Benjamin Thery" <ben.thery@...il.com> Cc: netdev@...r.kernel.org, "David Miller" <davem@...emloft.net>, "Herbert Xu" <herbert@...dor.apana.org.au>, "" YOSHIFUJI Hideaki / 吉藤英明"" <yoshfuji@...ux-ipv6.org> Subject: Re: [PATCH] XFRM,IPv6: initialize ip6_dst_blackhole_ops.kmem_cachep Hi, "Benjamin Thery" <ben.thery@...il.com> writes: > On Tue, Sep 23, 2008 at 18:21, Arnaud Ebalard <arno@...isbad.org> wrote: >> Hi, >> >> With the switch to a default value of 1 for xfrm_larval_drop in commit >> 28faa979746b2352cd78a376bf9f52db953bda46 (ipsec: Make xfrm_larval_drop >> default to 1), what seems to be a bug manage to surface on one of my >> test box running today's net-next (*). >> >> When xfrm_tmpl_resolve() returns -EAGAIN in __xfrm_lookup(), the caller >> is returned -EREMOTE and is expected to install a blackhole route. For >> IPv6, the call to dst_alloc(&ip6_dst_blackhole_ops) performed by >> ip6_dst_blackhole() produces the error provided below, because >> kmem_cachep attribute seems to be uninitialized. This does not happen >> when xfrm_larval_drop is set to 0. >> >> The patch below againt today's net-next fixes the issue but I am unable >> to tell if it is the best way (or even a decent way) to do it. >> >> Note that I am able to reproduce the issue on current 2.6.27-rc7 by >> forcing xfrm_larval_drop to 1. The patch below solves the problem, >> i.e. this may be a candidate for 2.6.27-rc8 (if correct). >> >> I may have missed something. Comments welcome. >> >> Cheers, >> >> a+ >> >> (*): with the small MIGRATE patch David commented some days ago applied >> on top of it. No interaction expected. >> >> >> >> From: Arnaud Ebalard <arno@...isbad.org> >> Date: Tue, 23 Sep 2008 16:59:04 +0200 >> Subject: [PATCH] XFRM,IPv6: initialize ip6_dst_blackhole_ops.kmem_cachep >> >> ip6_dst_blackhole_ops.kmem_cachep is not expected to be NULL (i.e. to >> be initialized) when dst_alloc() is called from ip6_dst_blackhole(). >> Otherwise, it results in the following (xfrm_larval_drop is now set to >> 1 by default): >> >> [ 78.697642] Unable to handle kernel paging request for data at address 0x0000004c >> [ 78.703449] Faulting instruction address: 0xc0097f54 >> [ 78.786896] Oops: Kernel access of bad area, sig: 11 [#1] >> [ 78.792791] PowerMac >> [ 78.798383] Modules linked in: btusb usbhid bluetooth b43 mac80211 cfg80211 ehci_hcd ohci_hcd sungem sungem_phy usbcore ssb >> [ 78.804263] NIP: c0097f54 LR: c0334a28 CTR: c002d430 >> [ 78.809997] REGS: eef19ad0 TRAP: 0300 Not tainted (2.6.27-rc5) >> [ 78.815743] MSR: 00001032 <ME,IR,DR> CR: 22242482 XER: 20000000 >> [ 78.821550] DAR: 0000004c, DSISR: 40000000 >> [ 78.827278] TASK = eef0df40[3035] 'mip6d' THREAD: eef18000 >> [ 78.827408] GPR00: 00001032 eef19b80 eef0df40 00000000 00008020 eef19c30 00000001 00000000 >> [ 78.833249] GPR08: eee5101c c05a5c10 ef9ad500 00000000 24242422 1005787c 00000000 1004f960 >> [ 78.839151] GPR16: 00000000 10024e90 10050040 48030018 0fe44150 00000000 00000000 eef19c30 >> [ 78.845046] GPR24: eef19e44 00000000 eef19bf8 efb37c14 eef19bf8 00008020 00009032 c0596064 >> [ 78.856671] NIP [c0097f54] kmem_cache_alloc+0x20/0x94 >> [ 78.862581] LR [c0334a28] dst_alloc+0x40/0xc4 >> [ 78.868451] Call Trace: >> [ 78.874252] [eef19b80] [c03c1810] ip6_dst_lookup_tail+0x1c8/0x1dc (unreliable) >> [ 78.880222] [eef19ba0] [c0334a28] dst_alloc+0x40/0xc4 >> [ 78.886164] [eef19bb0] [c03cd698] ip6_dst_blackhole+0x28/0x1cc >> [ 78.892090] [eef19be0] [c03d9be8] rawv6_sendmsg+0x75c/0xc88 >> [ 78.897999] [eef19cb0] [c038bca4] inet_sendmsg+0x4c/0x78 >> [ 78.903907] [eef19cd0] [c03207c8] sock_sendmsg+0xac/0xe4 >> [ 78.909734] [eef19db0] [c03209e4] sys_sendmsg+0x1e4/0x2a0 >> [ 78.915540] [eef19f00] [c03220a8] sys_socketcall+0xfc/0x210 >> [ 78.921406] [eef19f40] [c0014b3c] ret_from_syscall+0x0/0x38 >> [ 78.927295] --- Exception: c01 at 0xfe2d730 >> [ 78.927297] LR = 0xfe2d71c >> [ 78.939019] Instruction dump: >> [ 78.944835] 91640018 9144001c 900a0000 4bffff44 9421ffe0 7c0802a6 bf810010 7c9d2378 >> [ 78.950694] 90010024 7fc000a6 57c0045e 7c000124 <83e3004c> 8383005c 2f9f0000 419e0050 >> [ 78.956464] ---[ end trace 05fa1ed7972487a1 ]--- >> >> Signed-off-by: Arnaud Ebalard <arno@...isbad.org> > > Looks like I introduced this bug in commit > f2fc6a54585a1be6669613a31fbaba2ecbadcd36, > while adding network namespaces support to ipv6 routes. Thanks, this should be added to the report. In the end, it also seems like the patch is a good candidate for -stable (2.6.26 is impacted). I will let David add the stable team in CC if this is ok. > > Thanks for the fix. > > Acked-by: Benjamin Thery <benjamin.thery@...l.net> > >> --- >> net/ipv6/route.c | 2 ++ >> 1 files changed, 2 insertions(+), 0 deletions(-) >> >> diff --git a/net/ipv6/route.c b/net/ipv6/route.c >> index 776871e..f4385a6 100644 >> --- a/net/ipv6/route.c >> +++ b/net/ipv6/route.c >> @@ -2708,6 +2708,8 @@ int __init ip6_route_init(void) >> if (ret) >> goto out_kmem_cache; >> >> + ip6_dst_blackhole_ops.kmem_cachep = ip6_dst_ops_template.kmem_cachep; >> + >> /* Registering of the loopback is done before this portion of code, >> * the loopback reference in rt6_info will not be taken, do it >> * manually for init_net */ >> -- >> 1.5.6.3 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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