dmesg 程序崩溃调试2

dmesg命令基于缓冲区打印信息
dmesg -c可以清除该内存信息
清除后demsg 命令不显示任何信息,但可以到/var/log/dmesg查看信息

dmesg |tail 20
dmesg |head 20
dmesg |grep sda
dmesg |grep tty
dmesg |grep memory
dmesg |grep DMA
dmesg |grep usb

[root@localhost var]# dmesg | more
Linux version .. (root@localhost.localdomain) (gcc version ..  (Red Hat ..-))
 # SMP Sun Sep  :: PDT
Command line: ro root=LABEL=/ rhgb quiet
KERNEL supported cpus:
  Intel GenuineIntel
  AMD AuthenticAMD
  Centaur CentaurHauls
BIOS-provided physical RAM map:
 BIOS-e820:  - 000000000009f400 (usable)
 BIOS-e820: 000000000009f400 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000ca000 - 00000000000cc000 (reserved)
 BIOS-e820: 00000000000dc000 -  (reserved)
 BIOS-e820:  - 0000000057ee0000 (usable)
 BIOS-e820: 0000000057ee0000 - 0000000057eff000 (ACPI data)
 BIOS-e820: 0000000057eff000 - 0000000057f00000 (ACPI NVS)
 BIOS-e820: 0000000057f00000 -  (usable)
 BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
 BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
 BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
 BIOS-e820: 00000000fffe0000 -  (reserved)
DMI present.
Phoenix BIOS detected: BIOS may corrupt low RAM, working around it.
e820 update range:  -  (usable) ==> (reserved)
last_pfn = 0x58000 max_arch_pfn = 0x400000000
MTRR default type: uncachable
MTRR fixed ranges enabled:
  -9FFFF write-back
  A0000-BFFFF uncachable
  C0000-CBFFF write-protect
  CC000-EFFFF uncachable
  F0000-FFFFF write-protect

[root@localhost var]# dmesg | less
Linux version .. (root@localhost.localdomain) (gcc version ..  (Red Hat ..-))
 # SMP Sun Sep  :: PDT
Command line: ro root=LABEL=/ rhgb quiet
KERNEL supported cpus:
  Intel GenuineIntel
  AMD AuthenticAMD
  Centaur CentaurHauls
BIOS-provided physical RAM map:
 BIOS-e820:  - 000000000009f400 (usable)
 BIOS-e820: 000000000009f400 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000ca000 - 00000000000cc000 (reserved)
 BIOS-e820: 00000000000dc000 -  (reserved)
 BIOS-e820:  - 0000000057ee0000 (usable)
 BIOS-e820: 0000000057ee0000 - 0000000057eff000 (ACPI data)
 BIOS-e820: 0000000057eff000 - 0000000057f00000 (ACPI NVS)
 BIOS-e820: 0000000057f00000 -  (usable)
 BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
 BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
 BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
 BIOS-e820: 00000000fffe0000 -  (reserved)
DMI present.
Phoenix BIOS detected: BIOS may corrupt low RAM, working around it.
e820 update range:  -  (usable) ==> (reserved)
last_pfn = 0x58000 max_arch_pfn = 0x400000000
MTRR default type: uncachable
MTRR fixed ranges enabled:
  -9FFFF write-back
  A0000-BFFFF uncachable
  C0000-CBFFF write-protect
  CC000-EFFFF uncachable
  F0000-FFFFF write-protect

[root@localhost var]# dmesg | tail
Bluetooth: L2CAP socket layer initialized
Bluetooth: RFCOMM TTY layer initialized
Bluetooth: RFCOMM socket layer initialized
Bluetooth: RFCOMM ver .
Bluetooth: HIDP (Human Interface Emulation) ver .
eth0: no IPv6 routers present
hdc: task_pio_intr: status=0x51 { DriveReady SeekComplete Error }
hdc: task_pio_intr: error=0x04 { AbortedCommand }
hdc: possibly failed opcode: 0xec
xx[]: segfault at  ip  sp 00007fff206b7d60 error  in xx[+]

[root@localhost var]# dmesg | grep ttyS*
console [tty0] enabled
serial8250: ttyS0 at I/O 0x3f8 (irq = ) is a 16550A
serial8250: ttyS1 at I/O 0x2f8 (irq = ) is a 16550A
:0a: ttyS0 at I/O 0x3f8 (irq = ) is a 16550A
:0b: ttyS1 at I/O 0x2f8 (irq = ) is a 16550A
You have new mail in /var/spool/mail/root

dmesg -c    清除缓存

tail -n 20 /var/log/dmesg

[root@localhost log]# tail -n  /var/log/dmesg
Floppy drive(s): fd0 is .44M
FDC  is a post-
ide-cd driver .
ide-cd: hdc: ATAPI 1X DVD-ROM DVD-R/RAM CD-R/RW drive, 32kB Cache
Uniform CD-ROM driver Revision: .
sd :::: Attached scsi generic sg0 type
lp0: using parport0 (interrupt-driven).
lp0: console ready
NET: Registered protocol family
lo: Disabled Privacy Extensions
md: Autodetecting RAID arrays.
md: Scanned  and added  devices.
md: autorun ...
md: ... autorun DONE.
device-mapper: multipath: version .. loaded
EXT3 FS on sda2, internal journal
kjournald starting.  Commit interval  seconds
EXT3 FS on sda1, internal journal
EXT3-fs: mounted filesystem with writeback data mode.
Adding 2064344k swap on /dev/sda3.  Priority:- extents: across:2064344k 

[root@localhost log]# tail -n  messages
May  :: localhost avahi-daemon[]: Server startup complete. Host name is localhost.local. Local service cookie is .
May  :: localhost avahi-daemon[]: Service "SFTP File Transfer on localhost" (/services/sftp-ssh.service) successfully established.
May  :: localhost smartd[]: smartd version . [x86_64-redhat-linux-gnu] Copyright (C) - Bruce Allen
May  :: localhost smartd[]: Home page is http://smartmontools.sourceforge.net/
May  :: localhost smartd[]: Opened configuration file /etc/smartd.conf
May  :: localhost smartd[]: Configuration file /etc/smartd.conf was parsed, found DEVICESCAN, scanning devices
May  :: localhost smartd[]: Device: /dev/hdc, opened
May  :: localhost smartd[]: Device: /dev/hdc, not ATA, no IDENTIFY DEVICE Structure
May  :: localhost kernel: hdc: task_pio_intr: status=0x51 { DriveReady SeekComplete Error }
May  :: localhost kernel: hdc: task_pio_intr: error=0x04 { AbortedCommand }
May  :: localhost kernel: hdc: possibly failed opcode: 0xec
May  :: localhost smartd[]: Device: /dev/sda, opened
May  :: localhost smartd[]: Device: /dev/sda, IE (SMART) not enabled, skip device Try 'smartctl -s on /dev/sda' to turn on SMART features
May  :: localhost smartd[]: Monitoring  ATA and  SCSI devices
May  :: localhost smartd[]: smartd has fork()ed into background mode. New PID=.
May  :: localhost gdm[]: gdm_config_parse: Logdir /var/log/gdm does not exist or isn't a directory.  Using ServAuthDir /var/gdm.
May 28 22:42:25 localhost pcscd: winscard.c:304:SCardConnect() Reader E-Gate 0 0 Not Found
May 28 22:42:25 localhost last message repeated 3 times
May 28 22:43:45 localhost kernel: xx[4107]: segfault at 0 ip 0000000000400454 sp 00007fff206b7d60 error 6 in xx[400000+1000]
May 28 22:45:06 localhost logger: Oracle Configuration Manager failed to establish a connection to Oracle. Reconfigure using /opt/oracle/112/ccr/bin/configCCR