Help: major pppoe regression since 2.6.35 (panic on first ppp conection)?

From: Joel Soete
Date: Sat Dec 18 2010 - 06:41:41 EST


Hello all,

Since a year now, I installed my favorite Debian testing on my new X86_64 platform on which I like to run my personal kernel config. And all was working fine since 2.6.35 was released.

The first time I experiment this issue, it was during a test of Ubuntu upgrade to the latest release 10.10 against which I open this bug report <https://bugs.launchpad.net/ubuntu/+source/linux/+bug/618636>: in short the system panicing on first connection to my ISP.

This still occurs to me on the latest ubuntu stock linux image 2.6.35 as well as on my personal config from vanilla sources.

As in general this kind of problem is quickly identified and solved, I do some more test with 2.6.36 and even 2.6.37-rc? releases, in smp or up config, with or without netfilter, with or without foreign nvidia graphical driver but this issue is still there for me?

Obviously, I also do some researches with google but without a lot of success. So I try to figure out when this pb appears in the development history and find out that it was already in 2.6.35-rc1. So I do more kind of rewind in time and all was working fine since 2.6.34-git5 but problems appears in 2.6.34-git[67]. For my pppoe issue, there are few changes that I tried to revert without success?

The latest related stuff I can discovered is this regression report 2.6.35 -> 2.6.36 <http://www.spinics.net/lists/netdev/msg145824.html> and the debugging patch proposed by Jarek Poplawski effectively drops the ppp interface but the system doesn't panic any more, so can I get following kernel log:
Dec 17 17:26:53 sidh2 kernel: [ 25.941424] eth1: Link up
Dec 17 17:26:53 sidh2 kernel: [ 25.941736] eth1: Link changed: 10Mbps, half duplex
Dec 17 17:26:53 sidh2 kernel: [ 26.266657] r8169 0000:08:00.0: eth0: link up
Dec 17 17:26:53 sidh2 kernel: [ 26.266662] r8169 0000:08:00.0: eth0: link up
Dec 17 17:26:53 sidh2 kernel: [ 26.829432] ip_tables: (C) 2000-2006 Netfilter Core Team
Dec 17 17:26:58 sidh2 kernel: [ 33.017352] ppdev: user-space parallel port driver
Dec 17 17:27:04 sidh2 kernel: [ 36.357885] eth0: no IPv6 routers present
Dec 17 17:27:04 sidh2 kernel: [ 36.517833] eth1: no IPv6 routers present
Dec 17 17:28:12 sidh2 kernel: [ 106.511762] BUG: unable to handle kernel NULL pointer dereference at (null)
Dec 17 17:28:12 sidh2 kernel: [ 106.511952] IP: [<ffffffff810e405b>] put_page+0x1b/0x180
Dec 17 17:28:12 sidh2 kernel: [ 106.512078] PGD 13c6f0067 PUD 134283067 PMD 0
Dec 17 17:28:12 sidh2 kernel: [ 106.512293] Oops: 0000 [#1] SMP
Dec 17 17:28:12 sidh2 kernel: [ 106.512456] last sysfs file: /sys/devices/virtual/sound/timer/uevent
Dec 17 17:28:12 sidh2 kernel: [ 106.512533] CPU 4
Dec 17 17:28:12 sidh2 kernel: [ 106.512584] Modules linked in: ppdev xt_TCPMSS xt_tcpmss xt_tcpudp iptable_mangle ip_tables x_tables lp nvidia(P) parport_pc parport agpgart i7core_edac edac_core tpm_tis tpm tpm_bios [last unloaded: scsi_wait_scan]
Dec 17 17:28:12 sidh2 kernel: [ 106.513674]
Dec 17 17:28:12 sidh2 kernel: [ 106.513742] Pid: 1821, comm: pppd Tainted: P 2.6.35-amd64-t3 #5 EX58-UD3R/EX58-UD3R
Dec 17 17:28:12 sidh2 kernel: [ 106.513838] RIP: 0010:[<ffffffff810e405b>] [<ffffffff810e405b>] put_page+0x1b/0x180
Dec 17 17:28:12 sidh2 kernel: [ 106.513982] RSP: 0018:ffff88013cecfe08 EFLAGS: 00010292
Dec 17 17:28:12 sidh2 kernel: [ 106.514056] RAX: 0000000000000030 RBX: 0000000000000000 RCX: 0000000000001733
Dec 17 17:28:12 sidh2 kernel: [ 106.514134] RDX: ffff88013c906640 RSI: ffff88013c906060 RDI: 0000000000000000
Dec 17 17:28:12 sidh2 kernel: [ 106.514211] RBP: ffff88013c86e900 R08: ffffffff81342b90 R09: 00000000ffe22e08
Dec 17 17:28:12 sidh2 kernel: [ 106.514288] R10: ffff88013cece000 R11: 0000000000000000 R12: 00000000080d5f42
Dec 17 17:28:12 sidh2 kernel: [ 106.514366] R13: ffff88013c86f400 R14: 000000000000000a R15: 00000000000005de
Dec 17 17:28:12 sidh2 kernel: [ 106.514444] FS: 0000000000000000(0000) GS:ffff880001f00000(0063) knlGS:00000000f75f5b20
Dec 17 17:28:12 sidh2 kernel: [ 106.514539] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b
Dec 17 17:28:12 sidh2 kernel: [ 106.514614] CR2: 0000000000000000 CR3: 000000013c758000 CR4: 00000000000006e0
Dec 17 17:28:12 sidh2 kernel: [ 106.514692] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Dec 17 17:28:12 sidh2 kernel: [ 106.514769] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Dec 17 17:28:12 sidh2 kernel: [ 106.514847] Process pppd (pid: 1821, threadinfo ffff88013cece000, task ffff88013c7ea120)
Dec 17 17:28:12 sidh2 kernel: [ 106.514941] Stack:
Dec 17 17:28:12 sidh2 kernel: [ 106.515008] 0000000000000000 0000000000000001 ffff88013c86e900 00000000080d5f42
Dec 17 17:28:12 sidh2 kernel: [ 106.515227] <0> ffff88013c86f400 ffffffff814288b7 ffff88013c523c00 ffff88013c86e900
Dec 17 17:28:12 sidh2 kernel: [ 106.515556] <0> ffff88013c523c00 ffffffff814283c1 ffff88013c86e900 ffffffff81342d1c
Dec 17 17:28:12 sidh2 kernel: [ 106.515948] Call Trace:
Dec 17 17:28:12 sidh2 kernel: [ 106.516022] [<ffffffff814288b7>] ? skb_release_data+0x77/0xd0
Dec 17 17:28:12 sidh2 kernel: [ 106.516099] [<ffffffff814283c1>] ? __kfree_skb+0x11/0x90
Dec 17 17:28:12 sidh2 kernel: [ 106.516176] [<ffffffff81342d1c>] ? ppp_read+0x18c/0x210
Dec 17 17:28:12 sidh2 kernel: [ 106.516252] [<ffffffff8104df70>] ? default_wake_function+0x0/0x20
Dec 17 17:28:12 sidh2 kernel: [ 106.516329] [<ffffffff8111f905>] ? vfs_read+0xb5/0x1a0
Dec 17 17:28:12 sidh2 kernel: [ 106.516404] [<ffffffff8111fa3e>] ? sys_read+0x4e/0x90
Dec 17 17:28:12 sidh2 kernel: [ 106.516479] [<ffffffff810996ff>] ? compat_sys_gettimeofday+0x9f/0xb0
Dec 17 17:28:12 sidh2 kernel: [ 106.516558] [<ffffffff8103eb8f>] ? sysenter_dispatch+0x7/0x2e
Dec 17 17:28:12 sidh2 kernel: [ 106.516632] Code: cc bb f8 ff 66 66 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec 28 48 89 5c 24 08 48 89 6c 24 10 48 89 fb 4c 89 64 24 18 4c 89 6c 24 20 <48> 8b 07 66 a9 00 c0 0f 85 13 01 00 00 f0 ff 4f 08 0f 94 c0 84
Dec 17 17:28:12 sidh2 kernel: [ 106.519823] RIP [<ffffffff810e405b>] put_page+0x1b/0x180
Dec 17 17:28:12 sidh2 kernel: [ 106.519945] RSP <ffff88013cecfe08>
Dec 17 17:28:12 sidh2 kernel: [ 106.520015] CR2: 0000000000000000
Dec 17 17:28:12 sidh2 kernel: [ 106.520093] ---[ end trace bac76655d5f488ec ]---


Sorry but I don't have enough knowledge to understand this pb, so all help will be appreciated.

Tia,
J.

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