- Addresses FC7/upstream x86 kernels that have been configured such that the vmlinux symbol values do not match their relocated values when loaded. If CONFIG_PHYSICAL_START contains an value that is greater then CONFIG_PHYSICAL_ALIGN, then this mismatch occurs. Since the crash utility and its embedded gdb have always expected that the compiled-in kernel symbol addresses are "real", the virtual to physical translation fails, leading to an initialization-time failure with the message: "crash: vmlinux and /dev/crash do not match!" (/dev/mem or the dumpfile name may replace /dev/crash). To deal with this issue, there are several alternatives: 1) Configure the kernel with CONFIG_PHYSICAL_START less than or equal to CONFIG_PHYSICAL_ALIGN. Having done that, there is no problem; the resultant vmlinux file will be loaded at the address for which it was compiled, which has always been the case. 2) Since /proc/kallsyms uses the same format as a System.map file, and since it reflects the relocated symbol addresses, it can be placed on the crash command line as if it were a System.map file. (Note that the System.map file created by these relocated kernels contains the same "wrong" symbol values as the vmlinux file from which it was created.) 3) On a live system that has /proc/kallsyms (i.e., the kernel was configured with CONFIG_KALLSYMS), this version of the crash utility will replace/patch the vmlinux symbol values with those seen in /proc/kallsyms. The relocation value will be displayed as a WARNING message during initialization. 4) On a dumpfile, the relocation will not be performed automatically as on a live system. It will require the addition of the /proc/kallsyms on the command line, or if run on a different host, a copy of the crashed system's /proc/kallsyms may be used. 5) Alternatively on a dumpfile, a new command line option has been created to specify the relocation amount. For example, if a kernel was configured with a CONFIG_PHYSICAL_START value of 16MB and a CONFIG_PHYSICAL_ALIGN of 4MB, that results in a relocation of 12MB. To specify that, enter "crash --reloc=12m ..." on the command line. (Recall that if crash is run on the live system, a WARNING message will specify the relocation amount.) Using /proc/kallsyms or a --reloc=[size] as a command line argument is similar to using a System.map file, in that it results in the loss of the use of line number debug data. (anderson(a)redhat.com) - Fix for x86 2.6.22 kernel initialization-time failure indicating: "crash: invalid size request: 0 type: __per_cpu_offset" (oomichi(a)mxs.nes.nec.co.jp) - Fix to recognize the 2.6.22 kernel's replacement of kmalloc slab subsystem from the "./mm/slab.c" file to CONFIG_SLUB-configured kernels that use the infrastructure in "./mm/slub.c". Without this fix, crash sessions would fail during initialization with the message "crash: invalid structure member offset: kmem_cache_s_c_num". (anderson(a)redhat.com) - Cliff Wickman sent an additional patch for the LKCD kerntypes support he introduced in version 4.0-4.4, which addresses this message that is seen during initialization on 2.6.22 kernels: "WARNING: cannot determine pgdat list for this kernel/architecture". (cpw(a)sgi.com) - NOTE: The CONFIG_SLUB change in the 2.6.22 kernel will require a significant update in the crash utility in order for "kmem -[sS]" options to work again. - NOTE: 2.6.22 kernels have replaced the O(1) scheduler with the new CFS scheduler. As a result, the "runq" command fails, which will require a crash utility update to recognize and display the contents of each cpu's run queue. Download from: http://people.redhat.com/anderson