RHBA-2013:0010 - Bug Fix Advisory

Topic

Updated strace packages that fix multiple bugs are now available for Red Hat
Enterprise Linux 5.

Description

The strace packages provide a utility to intercept and record the system calls
called and received by a running process. The strace utility can print a record
of each system call, its arguments and its return value. The strace utility is
useful for diagnosing, debugging and instructional purposes.

This update fixes the following bugs:

• Prior to this update, the strace utility incorrectly decoded system calls when

tracing a 32 bit process on a 64 bit machine, because strace on IBM System z
platforms is not multi-arch aware. This update provides an additional strace
executable (strace32) which can be used to trace 32 bit processes on 64 bit
machines. (BZ#495935)

• Prior to this update, the strace utility incorrectly exited a system call loop

when the child process was interrupted. As a consequence, strace reported that
the last system call exited with a ERESTART_RESTARTBLOCK condition. This update
modifies the loop exit so that strace now correctly reports that the interrupted
system call is unfinished. (BZ#509152)

• Prior to this update, the kernel could, under certain circumstances, fail to

send a SIGTRAP signal to the strace utility. As a consequence, the strace
utility could become suspended if the target process blocked the debugging
signal SIGTRAP. With this update, strace now checks for this situation and
re-synchronizes with system call notifications when necessary. (BZ#512692)

• Prior to this update, traces were not detached but forcefully terminated when

the SIGTERM signal terminated the strace process while the trace executed a fork
or a cloned system call. This update modifies the underlying code to cleanly
detach traces when a strace process is terminated. (BZ#552964)

• Prior to this update, the strace utility incorrectly printed 64 bit arguments

for certain system calls such as "fadvise". This update modifies the underlying
code so that the correct "fadvise" arguments are printed as expected.
(BZ#571437)

• Prior to this update, a misinterpreted status caused strace to leave the

traced process in a stopped state when detaching from a process. This update
modifies the underlying code to leave the process in the correct state after
detaching. (BZ#580211)

• Prior to this update, the strace utility extracted arguments for the

"semtimedop" system call from the wrong location on the IBM System z platforms.
As a consequence, arguments for the "semtimedop" system call were incorrectly
displayed. This update modifies strace to extract the arguments from the correct
memory location so that the arguments for the "semtimedop" system call are
displayed as expected. (BZ#759566)

• Prior to this update, the strace utility did not correctly track switches

between 32-bit and 64-bit process execution domains, so called "personalities",
when tracing multiple processes with multiple "personalities". As a consequence,
strace logged the wrong system call names and arguments for the traced
processes. This update corrects personality tracking in strace so that it now
prints system call names and arguments as expected. (BZ#768203)

All users of strace are advised to upgrade to these updated packages, which fix
these bugs.

Solution

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

This update is available via the Red Hat Network. Details on how to use the Red
Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

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 - 495935 - s390x strace problems with 31-bit executables
• BZ - 571437 - strace incorrectly shows the arguments of fadvise() in 32 bit compat programs

CVEs

(none)

References

(none)