1.39. glibc

1.39.1. RHBA-2011:0109: bug fix and enhancement update

Updated glibc packages that fix several bugs and add an enhancement are now available for Red Hat Enterprise Linux 5.
The glibc packages contain the standard C libraries used by multiple programs on the system. These packages contain the standard C and the standard math libraries. Without these two libraries, the Linux system cannot function properly.
These updated glibc packages provide fixes for the following bugs:
* Executing the 'memusage' command (provided by the memusage utility, which is a part of the glibc-devel package) could cause a segmentation fault. This update fixes the found deficiency and the 'memusage' command works as expected. ( BZ#531576)
* Prior to this update, a DNS resolver could fail to report an appropriate error when the supplied buffer was too small. This resulted in a truncated response instead of asking the caller to resize the buffer and try again. With this update, small buffers are handled correctly and the DNS resolver no longer fails. ( BZ#533367)
* A deadlock that could cause an application to hang could occur when the 'dlclose' function was called. This resulted in the cancellation of a thread. With this update, a deadlock no longer occurs when calling the 'dlclose' function. ( BZ#549813)
* This update limits the amount of stack usage when adding an environment variable with a long name or value. ( BZ#559974)
* Submitting an AIO (Asynchronous Input/Output) write request requires a creation of a helper thread to handle the request. If the creation of this thread failed, a corruption of the glibc internal data structures could occur. This resulted in a crash when the next AIO request was submitted. This update corrects this issue by making sure the internal data structures remain consistent. ( BZ#566712)
* Previously, there was an error in the POWER6 implementation of the 'memcpy' and 'memset' functions. As a result, using Concurrent Versions System (CVS) with Kerberos authentication on the 32-bit PowerPC architecture may have failed with a segmentation fault. This error has been fixed, and both 'memcpy' and 'memset' functions now work as expected. ( BZ#579011)
* Due to a race in the 'free()' function, enabling 'MALLOC_CHECK_' could cause a segmentation fault. This update adds proper locking in the 'free()' function to prevent the aforementioned segmentation fault. ( BZ#585674)
* Under certain conditions, cancellation of a thread did not invoke a cleanup handler. This update adds more complete information to the unwind library for glibc, thus, when canceling a thread, a cleanup handler is invoked before the thread is terminated under all circumstances. ( BZ#593047)
* Under certain circumstances, unloading a module could leave the remaining modules' symbol search list in an inconsistent state. Consequent to this inconsistency, symbol lookups could spuriously fail to find the symbol. This update corrects this: module unloading no longer produces inconsistent state in the symbol search list. ( BZ#593675)
* Previously, pattern matching of specific digraphs was not consistent across all architectures. This was caused by a misinterpretation of the locale's collation information. With this update, the digraphs are correctly recognized and properly collated. ( BZ#601294)
* A race condition between module loading and stack unwinding could result in a crash. With this update, a crash no longer occurs in the aforementioned case. ( BZ#649956)
In addition, these updated glibc packages provide the following enhancement:
* The name service cache daemon (nscd) now prepends a timestamp to its log messages. ( BZ#527558)
* Support for POWER7 and Power ISA v.2.06 architectures has been added. ( BZ#563563), ( BZ#563599)
Users are advised to upgrade to these updated glibc packages, which resolve these issues and add this enhancement.

1.39.2. RHBA-2010:0769: bug fix update

Updated glibc packages that resolve an issue are now available.
The glibc packages contain the standard C libraries used by multiple programs on the system. These packages contain the standard C and the standard math libraries. Without these two libraries, the Linux system cannot function properly.
These updated glibc packages fix the following bug:
* When the 'MALLOC_CHECK_' feature was enabled, a race condition in the 'free' function resulted in an internal heap corruption in a multi-threaded application. With this update, proper locking was added to prevent the corruption. ( BZ#637067)
All users of glibc are advised to upgrade to these updated packages, which resolve this issue.

1.39.3. RHBA-2010:0562: bug fix update

Updated glibc packages that fix various bugs are now available.
The glibc packages contain the standard C libraries used by multiple programs on the system. These packages contain the standard C and the standard math libraries. Without these two libraries, the Linux system cannot function properly.
This update fixes the following bugs:
* under certain circumstances, unloading a module could leave the remaining modules' symbol search list in an inconsistent state. Consequent to this inconsistency, symbol lookups could spuriously fail to find the symbol. This update corrects this: module unloading no longer produces inconsistent state in the symbol search list. ( BZ#604193)
* previously, there was an error in the POWER6 implementation of the "memcpy" and "memset" functions. As a result, using Concurrent Versions System (CVS) with Kerberos authentication on the 32-bit PowerPC architecture may have failed with a segmentation fault. This error has been fixed, and both "memcpy" and "memset" functions now work as expected. ( BZ#614546)
All users are advised to upgrade to these updated packages, which resolve these issues.

1.39.4. RHBA-2010:0450: bug fix update

Updated glibc packages that fix two bugs are now available.
The glibc packages contain the standard C libraries used by multiple programs on the system. These packages contain the standard C and the standard math libraries. Without these two libraries, the Linux system cannot function properly.
This update applies the following bug fixes:
* submitting an AIO write request initially requires creating a helper thread to handle the request. If the creation of this thread fails, a corruption of glibc internal data structures can result which can cause a crash when the next AIO request is submitted. This update corrects this by making sure the internal structures remain consistent. ( BZ#589871)
* missing unwind information can cause pthread cleanup handlers to be missed when a thread is canceled. This update adds unwind information to all functions in the standard C library, even on platforms that do not emit such information by default. ( BZ#593047)
All users are advised to upgrade to these updated packages, which resolve these issue.