RHBA-2011:0059 - Bug Fix Advisory

Topic

An updated crash package that fixes various bugs is now available for Red Hat
Enterprise Linux 5.

Description

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.

This update fixes the following bugs:

• Under certain circumstances, running the "mach -m" command on x86, Intel 64,

and AMD64 architectures may have failed with a segmentation fault. This occurred
when the e820 map provided by BIOS contained an Extensible Firmware Interface
(EFI) entry with a value that had not been mapped to the "E820" type. With this
update, the underlying source code has been modified to target this issue, and
the above command now produces the expected output. (BZ#569164)

• Prior to this update, running the "bt" command on an x86 architecture may have

failed with the following error message:

bt: cannot resolve stack trace

This occurred when a task that received a non-maskable interrupt (NMI) entered
the kernel from user space, but had not called the requested system call
function yet, or when the copy_thread() function set the Extended Instruction
Pointer (EIP) value of a newly forked task to the "ret_from_fork" entry point.
This has been fixed, and the "bt" command now works as expected. (BZ#572605)

• When running the "kmem -s list" command, the crash utility was unable to read

the "kmem_cache_s.name" string. To resolve this issue, the utility has been
adjusted to skip the "list_head", and the above command now displays the actual
"kmem_cache" names or addresses only. (BZ#580589)

• On a PowerPC architecture, booting a kernel with the "smt-enabled=off" option

caused the initial system information, as well as the "sys" and "mach" commands
to display an incorrect CPU count. This error has been fixed, and the crash
utility now always displays the correct number of available CPUs. (BZ#580599)

• On Intel 64 and AMD64 architectures, running the "bt" command may have failed

to produce a correct backtrace when an NMI-interrupted task did not manage to
switch its stack pointer from the user-space to kernel stack yet. This error no
longer occurs, and the "bt" command now produces the correct output. (BZ#593066)

• The crash utility has been updated to recognize the "__rhel5" marker that

flags the difference between the upstream and Red Hat KVM "virsh dump" CPU
device format in the dump file header. (BZ#603027)

• Prior to this update, the "bt" command failed to make the transition from the

NMI exception stack to the process stack when a task had just entered the
kernel, but had not switched its stack pointer from the user-space per-thread
stack to the relevant kernel stack yet. This has been fixed, and such transition
is made as expected. (BZ#608171)

• The "bt" command was unable to make the transition from the soft IRQ stack to

the process stack when a task had taken a clock interrupt and crashed in the
subsequent soft IRQ handler. With this update, such transition no longer fails.
(BZ#608714)

• On an x86 architecture, the "bt" command may have occasionally failed to

produce the backtrace of an NMI-interrupted idle task. This error has been
fixed, and the correct output is now displayed as expected. (BZ#653288)

• Previously, using the "bt" command to backtrace the VCPU of a Xen hypervisor

may have failed to return the correct result. This happened when the VCPU
received an NMI interrupt while it was running in a particular location in the
hypercall entry point, and in certain interrupt handlers. This error has been
fixed, and using "bt" to backtrace such VCPU now produces the expected output.
(BZ#653823)

• When running the "kmem -s" command on a large, active live system, a glibc

error may have caused the utility to terminate with a segmentation fault. With
this update, an upstream patch has been applied to target this issue, and the
segmentation fault no longer occurs. (BZ#659593)

Users of crash are advised to upgrade to this updated package, which resolves
these issues.

Solution

Before applying this update, make sure that all previously-released errata
relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use the Red
Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 569164 - 'mach -m' causes segmentation fault when analysing live system
• BZ - 572605 - [5.5] backtrace subcommand of crash command fails.
• BZ - 580589 - "kmem -s list" sub-commands in crash utility doesn't work
• BZ - 603027 - [RHEL5] crash needs to support (or distinguish between) both upstream version 9 and RHEL5 version 9
• BZ - 608171 - [RHEL5] possibly bogus exception frame -- NMI while running on thread user stack
• BZ - 608714 - [RHEL5] cannot resolve stack trace -- apic_timer_interrupt soft IRQ handler
• BZ - 653288 - [REG][5.6]backtrace subcommand of crash command fails.
• BZ - 653823 - bt: cannot resolve stack trace when analysing dom0's vmcore
• BZ - 659593 - kmem -s triggered a glibc-type error when analysing live system

CVEs

(none)

References

(none)