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# BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 IP: [<ffffffff821ed01e>] listening_get_next+0x50/0x1b3 PGD 11e4b9067 PUD 11d16c067 PMD 0 Oops: 0000 [1] SMP last sysfs file: /sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map CPU 3 Modules linked in: bridge ipv6 button battery ac loop dm_mod tg3 ext3 jbd edd fan thermal processor thermal_sys hwmon sg sata_svw libata dock serverworks sd_mod scsi_mod ide_disk ide_core [last unloaded: freq_table] Pid: 3368, comm: slpd Not tainted 2.6.26-rc2-mm1-lxc4 #1 RIP: 0010:[<ffffffff821ed01e>] [<ffffffff821ed01e>] listening_get_next+0x50/0x1b3 RSP: 0018:ffff81011e1fbe18 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8100be0ad3c0 RCX: ffff8100619f50c0 RDX: ffffffff82475be0 RSI: ffff81011d9ae6c0 RDI: ffff8100be0ad508 RBP: ffff81011f4f1240 R08: 00000000ffffffff R09: ffff8101185b6780 R10: 000000000000002d R11: ffffffff820fdbfa R12: ffff8100be0ad3c8 R13: ffff8100be0ad6a0 R14: ffff8100be0ad3c0 R15: ffffffff825b8ce0 FS: 00007f6a0ebd16d0(0000) GS:ffff81011f424540(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000038 CR3: 000000011dc20000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process slpd (pid: 3368, threadinfo ffff81011e1fa000, task ffff81011f4b8660) Stack: 00000000000002ee ffff81011f5a57c0 ffff81011f4f1240 ffff81011e1fbe90 0000000000001000 0000000000000000 00007fff16bf2590 ffffffff821ed9c8 ffff81011f5a57c0 ffff81011d9ae6c0 000000000000041a ffffffff820b0abd Call Trace: [<ffffffff821ed9c8>] ? tcp_seq_next+0x34/0x7e [<ffffffff820b0abd>] ? seq_read+0x1aa/0x29d [<ffffffff820d21b4>] ? proc_reg_read+0x73/0x8e [<ffffffff8209769c>] ? vfs_read+0xaa/0x152 [<ffffffff82097a7d>] ? sys_read+0x45/0x6e [<ffffffff8200bd2b>] ? system_call_after_swapgs+0x7b/0x80 Code: 31 a9 25 00 e9 b5 00 00 00 ff 45 20 83 7d 0c 01 75 79 4c 8b 75 10 48 8b 0e eb 1d 48 8b 51 20 0f b7 45 08 39 02 75 0e 48 8b 41 28 <4c> 39 78 38 0f 84 93 00 00 00 48 8b 09 48 85 c9 75 de 8b 55 1c RIP [<ffffffff821ed01e>] listening_get_next+0x50/0x1b3 RSP <ffff81011e1fbe18> CR2: 0000000000000038 This kernel panic appears with CONFIG_NET_NS=y. How to reproduce ? On the buggy host (host A) * ip addr add 1.2.3.4/24 dev eth0 On a remote host (host B) * ip addr add 1.2.3.5/24 dev eth0 * iptables -A INPUT -p tcp -s 1.2.3.4 -j DROP * ssh 1.2.3.4 On host A: * netstat -ta or cat /proc/net/tcp This bug happens when reading /proc/net/tcp[6] when there is a req_sock at the SYN_RECV state. When a SYN is received the minisock is created and the sk field is set to NULL. In the listening_get_next function, we try to look at the field req->sk->sk_net. When looking at how to fix this bug, I noticed that is useless to do the check for the minisock belonging to the namespace. A minisock belongs to a listen point and this one is per namespace, so when browsing the minisock they are always per namespace. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| 9p | ||
| 802 | ||
| 8021q | ||
| appletalk | ||
| atm | ||
| ax25 | ||
| bluetooth | ||
| bridge | ||
| can | ||
| core | ||
| dccp | ||
| decnet | ||
| econet | ||
| ethernet | ||
| ieee80211 | ||
| ipv4 | ||
| ipv6 | ||
| ipx | ||
| irda | ||
| iucv | ||
| key | ||
| lapb | ||
| llc | ||
| mac80211 | ||
| netfilter | ||
| netlabel | ||
| netlink | ||
| netrom | ||
| packet | ||
| rfkill | ||
| rose | ||
| rxrpc | ||
| sched | ||
| sctp | ||
| sunrpc | ||
| tipc | ||
| unix | ||
| wanrouter | ||
| wireless | ||
| x25 | ||
| xfrm | ||
| compat.c | ||
| Kconfig | ||
| Makefile | ||
| nonet.c | ||
| socket.c | ||
| sysctl_net.c | ||
| TUNABLE | ||