diff options
Diffstat (limited to 'Documentation/kdump/kdump.txt')
| -rw-r--r-- | Documentation/kdump/kdump.txt | 27 |
1 files changed, 16 insertions, 11 deletions
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index 7ff213f4becd..5f08f9ce6046 100644 --- a/Documentation/kdump/kdump.txt +++ b/Documentation/kdump/kdump.txt @@ -39,8 +39,7 @@ SETUP and apply http://lse.sourceforge.net/kdump/patches/kexec-tools-1.101-kdump.patch and after that build the source. -2) Download and build the appropriate (latest) kexec/kdump (-mm) kernel - patchset and apply it to the vanilla kernel tree. +2) Download and build the appropriate (2.6.13-rc1 onwards) vanilla kernel. Two kernels need to be built in order to get this feature working. @@ -67,11 +66,11 @@ SETUP c) Enable "/proc/vmcore support" (Optional, in Pseudo filesystems). CONFIG_PROC_VMCORE=y d) Disable SMP support and build a UP kernel (Until it is fixed). - CONFIG_SMP=n + CONFIG_SMP=n e) Enable "Local APIC support on uniprocessors". - CONFIG_X86_UP_APIC=y + CONFIG_X86_UP_APIC=y f) Enable "IO-APIC support on uniprocessors" - CONFIG_X86_UP_IOAPIC=y + CONFIG_X86_UP_IOAPIC=y Note: i) Options a) and b) depend upon "Configure standard kernel features (for small systems)" (under General setup). @@ -84,17 +83,23 @@ SETUP 4) Load the second kernel to be booted using: - kexec -p <second-kernel> --crash-dump --args-linux --append="root=<root-dev> - init 1 irqpoll" + kexec -p <second-kernel> --args-linux --elf32-core-headers + --append="root=<root-dev> init 1 irqpoll" Note: i) <second-kernel> has to be a vmlinux image. bzImage will not work, as of now. - ii) By default ELF headers are stored in ELF32 format (for i386). This - is sufficient to represent the physical memory up to 4GB. To store - headers in ELF64 format, specifiy "--elf64-core-headers" on the - kexec command line additionally. + ii) By default ELF headers are stored in ELF64 format. Option + --elf32-core-headers forces generation of ELF32 headers. gdb can + not open ELF64 headers on 32 bit systems. So creating ELF32 + headers can come handy for users who have got non-PAE systems and + hence have memory less than 4GB. iii) Specify "irqpoll" as command line parameter. This reduces driver initialization failures in second kernel due to shared interrupts. + iv) <root-dev> needs to be specified in a format corresponding to + the root device name in the output of mount command. + v) If you have built the drivers required to mount root file + system as modules in <second-kernel>, then, specify + --initrd=<initrd-for-second-kernel>. 5) System reboots into the second kernel when a panic occurs. A module can be written to force the panic or "ALT-SysRq-c" can be used initiate a crash |