1.30. crash

An updated crash package that fixes various bugs and adds two enhancements is now available for Red Hat Enterprise Linux 6.
The crash package provides a self-contained tool that can be used to investigate live systems, and kernel core dumps created from the netdump, diskdump, kdump, and Xen/KVM "virsh dump" facilities from Red Hat Enterprise Linux.
The crash package has been upgraded to upstream version 5.1.1, which provides a number of bug fixes over the previous version. (BZ#649070)
Bug Fixes
On 64-bit x86 architectures, using the "bt" command to analyze core dumps from kernel 2.6.27 or later caused it to display an invalid "vgettimeofday" frame above the topmost "system_call_fastpath" frame, followed by two read error messages similar to the following:
bt: read error: kernel virtual address: ffffffffff600000  type: "gdb_readmem_callback"
This error no longer occurs, and the "bt" command now produces correct results for these kernels.
When analyzing a KVM dump file from a 64-bit x86 guest system, the crash utility failed to determine the starting RIP and RSP hooks. This rendered it unable to produce a correct backtrace for tasks that were either running in user space when the "virsh dump" operation was performed on a live guest, or that were running on interrupt or exception stacks. With this update, the RIP and RSP hooks for a particular dump file are now determined by using the content of the per-CPU registers in the CPU device format. As a result, the "bt" command no longer produces incorrect backtraces for such dump files.
When analyzing a KVM dump file from an x86 guest system, the crash utility was unable to determine the starting EIP and ESP hooks, and produced an invalid backtrace. With this update, the crash utility has been updated to use the 64-bit CPU device format in x86 KVM dump files by default, and only use the 32-bit format when it is determined that the host machine was running a 32-bit kernel. As a result, running the "bt" command when analyzing such a dump file now produces a correct backtrace.
When creating a KVM dump file, the "virsh dump" operation marks all non-crashing CPUs as offline. Due to an incorrect use of the "cpu_online_map" mask to determine the CPU count, previous version of the crash utility may have reported a wrong number of CPUs when analyzing dumps created by the "virsh dump" command on x86 guest systems. With this update, the underlying source code has been adapted to use the "cpu_present_map" mask instead, so that the crash utility reports the correct number of CPUs.
Prior to this update, an attempt to display a backtrace of a non-active swapper task on a 32-bit x86 architecture could cause the crash utility to display the following message:
bt: cannot resolve stack trace:
#0 [c09f1ef4] ia32_sysenter_target at c08208ce
This update applies a patch that resolves this issue, and the crash utility now resolves such backtraces as expected. Additionally, this update ensures that the crash utility is no longer negatively affected by the changes that were introduced in kernel 2.6.32-112.
The crash utility has been updated to provide support for dump files created on the IBM System z architecture.
The crash utility now supports compressed and/or filtered dump files generated by the makedumpfile utility on IBM System z.
All users of crash are advised to upgrade to this updated package, which fixes these bugs and adds these enhancements.