RHBA-2015:2089 - Bug Fix Advisory

Topic

Updated gdb packages that fix several bugs and add two enhancements are now available for Red Hat Enterprise Linux 7.

Description

The GNU Debugger (GDB) allows users to debug programs written in various programming languages including C, C++, and Fortran.

Notably, this update fixes the following bugs:

• GDB on 64-bit IBM Power Systems incorrectly deallocated a memory block that held the symbol table for the binary being debugged, which caused a segmentation fault when GDB tried to access that symbol table. To solve this problem, the specific memory block has been made persistent, and GDB can now access the needed information later during the debugging session, without reading an invalid memory region. (BZ#1190506)
• The ptrace system call requires resuming threads individually. While resuming threads of a process, for example, with the "continue" command, if an already-resumed thread N causes a process exit, for example, by calling the _exit() function, the resumption of the remaining threads fails with the ESRCH (No such process) error because the process no longer exists. Previously, GDB did not expect this scenario and aborted the resumption command with a "ptrace: No such process." error message. Consequently, a subsequent "detach" command then failed an internal assertion due to inconsistent internal state. With this update, if a thread disappears while being resumed, GDB proceeds to collect the thread's exit status. As a result, the resumption command ends with the expected "Inferior exited normally" message and the subsequent "detach" command no longer crashes in the described scenario. (BZ#1184724)
• While dealing with certain backtraces, for example, a corrupted stack with a cycle, GDB was incorrectly creating two frames with the same internal frame ID in the backtrace. Each frame having its unique internal ID is an invariant assumed throughout GDB. Consequently, GDB entered an infinite loop when trying to evaluate a value on the current frame, which then caused Out of Memory (OOM) killer to kill the GDB process. To address this problem, GDB has been fixed to explicitly check if there are no duplicate internal frame IDs during the backtrace unwinding process. If they are, processing of the backtrace is stopped and the user is warned about the possible stack corruption. As a result, GDB can now perform a backtrace without entering an infinite loop in the described scenario. (BZ#1225569)
• When GDB refreshes the thread list out of the libthread_db library, it finds a thread with PID -1 (the clone's parent), which is not yet on the thread list. Previously, GDB tried to attach to that bogus PID, which failed, and GDB emitted an internal error message. Consequently, if a pthreaded program had a thread that called clone(CLONE_VM) directly, and then that clone hit a debug event, for example, a breakpoint, GDB issued an internal error, which affected the debugging session. This problem occurred because the "clone" call cleared the parent thread's TID field in the glibc's thread data structure. GDB has been fixed to detect the bogus PID -1 earlier and to display a warning message to the user. As a result, the debugging session is no longer affected in the described scenario. (BZ#1210889)

This update adds the following enhancements:

• GDB now includes support for SystemTap Static Defined Tracing (SDT) probes on the 64-bit ARM architecture. This enables GDB to use the new, faster probes-based dynamic linker interface, which in turn improves the performance of loading shared libraries of a debugged program by orders of magnitude. (BZ#1247107)
• GDB is now able to perform reverse debugging to debug programs on PowerPC architectures. This can be done by using commands such as "record", "reverse-next", "reverse-step", or "reverse-continue". This feature greatly increases the productivity of the user debugging complex programs. (BZ#1218710)

Users of gdb are advised to upgrade to these updated packages, which fix these bugs and add these enhancements.

Solution

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 7 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for IBM z Systems 7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.5 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.3 s390x
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux for Power, little endian 7 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.7 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.6 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.5 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.4 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.3 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.2 ppc64le
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 7 s390x
• Red Hat Enterprise Linux EUS Compute Node 7.7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.7 ppc64le
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.6 ppc64le
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.4 ppc64le
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.3 ppc64le
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 ppc64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, little endian 7 ppc64le

Fixes

• BZ - 1084404 - [ppc64] and [s390x] wrong prologue skip on -O2 -g code
• BZ - 1149207 - `catch syscall' doesn't work for parent after `fork' is called
• BZ - 1184724 - gdb output a internal-error: Assertion `num_lwps (GET_PID (inferior_ptid)) == 1' failed
• BZ - 1190506 - ppc64: segv in `gdb -q /lib/modules/3.10.0-215.el7.ppc64/kernel/fs/nfsd/nfsd.ko`
• BZ - 1197665 - apply_frame_filter() wrong backport
• BZ - 1210135 - gdb/linux-nat.c:1411: internal-error: linux_nat_post_attach_wait: Assertion `pid == new_pid' failed.
• BZ - 1260558 - Unexpected output from gdb on ppc64le

CVEs

(none)

References

• http://www.redhat.com/security/updates/classification/#normal