kmsgdump for Linux 2.5.65/2.5.66 2003-03-31 version 0.4.5 Randy Dunlap Updated for Linux 2.5.75, 2003-07-17 kmsgdump home: http://w.ods.org/tools/kmsgdump/ (Willy Tarreau) my kmsgdump patches: http://www.xenotime.net/linux/kmsgdump/ kmsgdump is also available for Linux 2.4. See the kmsgdump home page for Linux 2.4 patches. ====================================================================== What is KMSGDUMP ? ~~~~~~~~~~~~~~~~~~ KMSGDUMP is an extension to the Linux kernel (for x86 systems) which allows the user on the console to dump the last kernel messages onto a floppy diskette or to a parallel printer (ones that the system BIOS knows about), thus avoiding the need to take a pen and a paper to copy them when the system is stuck. Only 3.5", 1.44 MB diskettes are supported by default. Other capacities might work, provided you change the geometry in the file "kmsgdump.h". kmsgdump dumps kernel messages to a parallel printer or to a floppy drive (A: or B:). The floppy media can be formatted as a FAT filesystem or used as a raw device. If it's a FAT filesystem, the kernel messages are saved in a file named MESSAGES.TXT. The kmsgdump documentation tells how to recover the messages from the floppy media. How does it work ? ~~~~~~~~~~~~~~~~~~ You can invoke kmsgdump in either of two ways: - manual: by pressing SysRQ+D (RightAlt-PrintScrn-D together); in this interactive mode, various kmsgdump modes and options can be changed. - automatic: after a kernel panic has occurred, a dump may be automatically generated. Please see the kmsgdump web site or the "kmsgdump.txt" file in the patch file for complete documentation and details. Summary ~~~~~~~ You can save yourself time and trouble by using kmsgdump to save kernel log messages to a floppy disk after a panic on an x86 system. Then you can email the kernel log messages to the appropriate Linux mailing list or to your Linux vendor for support. ====================================================================== Changes for Linux 2.6.0-test9, 2003-11-18 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - moved arch/i386/kernel/process.c patches to .../kmsg_reboot.c; Changes for 2.5.75 version ~~~~~~~~~~~~~~~~~~~~~~~~~~ - use kdebug() in machine_dump(), conditional on KDEBUG; - use kb_wait() and mach_reboot() funcs from mach_reboot.h; ====================================================================== caveats ~~~~~~~ 1. This version of kmsgdump doesn't support kernel log buffers of more than 60 KB (due to x86 real-mode segment addressing). However, the kernel log buffer is currently always a power of 2 (like 16 or 32 or 64 KB), so a 32 KB log buffer is the largest that is currently supported. Also, specifying 'log_buf_len=' on the kernel command line is not yet supporrted. 2. The kmsgdump text-mode interface doesn't work with a USB-only keyboard setup. I had to add a PS/2 keyboard to my test system to use it. kmsgdump can print only to parallel printers, not to USB printers. ###