Hi all, When using kdump, I find crash "bt" and "dmesg" give different info. which one is more reliable ? Thanks, ---cym dmesg /****************************************/ Unable to handle kernel NULL pointer dereference at 0000000000000001 RIP: [<0000000000000001>] PGD 323c6f067 PUD 323f13067 PMD 0 Oops: 0010 [1] SMP last sysfs file: /devices/pci0000:00/0000:00:00.0/irq CPU 6 Modules linked in: igb(U) bonding ipv6 xfrm_nalgo crypto_api autofs4 hidp rfcomm l2cap bluetooth lockd sunrpc dm_mirror dm_multipath scsi_dh video hwmon backlight sbs i2c_ec button battery asus_acpi acpi_memhotplug ac parport_pc lp parport sg ixgbe pcspkr i2c_i801 serio_raw i2c_core 8021q dca dm_raid45 dm_message dm_region_hash dm_log dm_mod dm_mem_cache ahci libata shpchp mptsas mptscsih mptbase scsi_transport_sas sd_mod scsi_mod ext3 jbd uhci_hcd ohci_hcd ehci_hcd Pid: 8894, comm: ifconfig Tainted: G 2.6.18-164.el5debug #1 RIP: 0010:[<0000000000000001>] [<0000000000000001>] RSP: 0018:ffff810323dd9cf0 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffff81032a8e5b68 RCX: 0000000000000000 RDX: 0000000000000006 RSI: 0000000000000001 RDI: ffff81032a8e5b68 RBP: ffff81033aabc850 R08: 0000000000000002 R09: 0000000000000001 R10: ffff81032a8e5c30 R11: ffffffff80049ee3 R12: ffff81032a8e5ba8 R13: 0000000000000006 R14: ffff8103238be000 R15: ffffffff8846ad00 FS: 00002ba7032083f0(0000) GS:ffff810113a9e4c8(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000001 CR3: 00000003242b4000 CR4: 00000000000006e0 Process ifconfig (pid: 8894, threadinfo ffff810323dd8000, task ffff810323f461c0) Stack: ffffffff8023de3b ffff81032a8e5b68 ffffffff8023e0d6 ffffffff8023e122 ffffffff88468eb0 ffff8103238be000 ffffffff8846ad00 ffff8103238be000 0000000000000000 ffffffff8846ae98 ffffffff8023e12d 0000000000000002 Call Trace: [<ffffffff8023de3b>] neigh_cleanup_and_release+0x13/0x2c [<ffffffff8023e0d6>] neigh_flush_dev+0x9d/0xc3 [<ffffffff88439acb>] :ipv6:ndisc_netdev_event+0x30/0x3d [<ffffffff8006ae76>] notifier_call_chain+0x20/0x32 [<ffffffff80238c52>] dev_close+0x6e/0x72 [<ffffffff80237d24>] dev_change_flags+0x5a/0x119 [<ffffffff8026cb77>] devinet_ioctl+0x235/0x59c [<ffffffff8022f0e3>] sock_ioctl+0x1c7/0x1eb [<ffffffff8004465d>] do_ioctl+0x21/0x6b [<ffffffff80031f07>] vfs_ioctl+0x45d/0x4bf [<ffffffff800c0b9d>] audit_syscall_entry+0x180/0x1b3 [<ffffffff8004ef9e>] sys_ioctl+0x59/0x78 [<ffffffff800602a6>] tracesys+0xd5/0xdf /****************************************/ crash btcrash> bt PID: 8894 TASK: ffff810323f461c0 CPU: 6 COMMAND: "ifconfig" #0 [ffff810323dd9a50] crash_kexec at ffffffff800b6eae #1 [ffff810323dd9b10] __die at ffffffff80069087 #2 [ffff810323dd9b50] do_page_fault at ffffffff8006ad73 #3 [ffff810323dd9c40] error_exit at ffffffff80060e9d #4 [ffff810323dd9c78] skb_dequeue at ffffffff80049ee3 #5 [ffff810323dd9cf0] neigh_cleanup_and_release at ffffffff8023de3b #6 [ffff810323dd9d00] neigh_flush_dev at ffffffff8023e0d6 #7 [ffff810323dd9d40] neigh_ifdown at ffffffff8023e12d #8 [ffff810323dd9d80] ndisc_netdev_event at ffffffff88439acb #9 [ffff810323dd9d90] notifier_call_chain at ffffffff8006ae76 #10 [ffff810323dd9db0] dev_close at ffffffff80238c52 #11 [ffff810323dd9dc0] dev_change_flags at ffffffff80237d24 #12 [ffff810323dd9df0] devinet_ioctl at ffffffff8026cb77 #13 [ffff810323dd9e90] sock_ioctl at ffffffff8022f0e3 #14 [ffff810323dd9eb0] do_ioctl at ffffffff8004465d #15 [ffff810323dd9ed0] vfs_ioctl at ffffffff80031f07 #16 [ffff810323dd9f40] sys_ioctl at ffffffff8004ef9e #17 [ffff810323dd9f80] tracesys at ffffffff800602a6 (via system_call) RIP: 0000003749ccc557 RSP: 00007fff470ea238 RFLAGS: 00000206 RAX: ffffffffffffffda RBX: ffffffff800602a6 RCX: ffffffffffffffff RDX: 00007fff470ea240 RSI: 0000000000008914 RDI: 0000000000000004 RBP: 0000000000000000 R8: 00007fff470ea244 R9: 0000000000000002 R10: 0000000000000001 R11: 0000000000000206 R12: 00007fff470ea360 R13: 00000000fffffffe R14: 00007fff470ea530 R15: 0000000000000004 ORIG_RAX: 0000000000000010 CS: 0033 SS: 002b