Moderate: kernel security and bug fix update

Updated kernel packages that fix one security issue and several bugs are
now available for Red Hat Enterprise Linux 5.

This update has been rated as having moderate security impact by the Red
Hat Security Response Team.

The kernel packages contain the Linux kernel, the core of any Linux
operating system.

Security fix:

* a NULL pointer dereference flaw was found in the Multiple Devices (md)
driver in the Linux kernel. If the "suspend_lo" or "suspend_hi" file on the
sysfs file system ("/sys/") is modified when the disk array is inactive, it
could lead to a local denial of service or privilege escalation. Note: By
default, only the root user can write to the files mentioned above.
(CVE-2009-2849, Moderate)

Bug fixes:

* a bug in nlm_lookup_host() could lead to un-reclaimed locks on file
systems, resulting in umount failing and NFS service relocation issues for
clusters. (BZ#517967)

* a bug in the sky2 driver prevented the phy from being reset properly on
some hardware when it hanged, preventing a link from coming back up.
(BZ#517976)

* disabling MSI-X for qla2xxx also disabled MSI interrupts. (BZ#519782)

* performance issues with reads when using the qlge driver on PowerPC
systems. A system hang could also occur during reboot. (BZ#519783)

* unreliable time keeping for Red Hat Enterprise Linux virtual machines.
The KVM pvclock code is now used to detect/correct lost ticks. (BZ#520685)

* /proc/cpuinfo was missing flags for new features in supported processors,
possibly preventing the operating system and applications from getting the
best performance. (BZ#520686)

* reading/writing with a serial loopback device on a certain IBM system did
not work unless booted with "pnpacpi=off". (BZ#520905)

* mlx4_core failed to load on systems with more than 32 CPUs. (BZ#520906)

* on big-endian platforms, interfaces using the mlx4_en driver and Large
Receive Offload (LRO) did not handle VLAN traffic properly (a segmentation
fault in the VLAN stack in the kernel occurred). (BZ#520908)

* due to a lock being held for a long time, some systems may have
experienced "BUG: soft lockup" messages under very heavy load. (BZ#520919)

* incorrect APIC timer calibration may have caused a system hang during
boot, as well as the system time becoming faster or slower. A warning is
now provided. (BZ#521238)

* a Fibre Channel device re-scan via 'echo "---" > /sys/class/scsi_host/
host[x]/scan' may not complete after hot adding a drive, leading to soft
lockups ("BUG: soft lockup detected"). (BZ#521239)

* the Broadcom BCM5761 network device was unable to be initialized
properly; therefore, the associated interface could not obtain an IP
address via DHCP, or be assigned one manually. (BZ#521241)

* when a process attempted to read from a page that had first been
accessed by writing to part of it (via write(2)), the NFS client needed to
flush the modified portion of the page out to the server, and then read
the entire page back in. This flush caused performance issues. (BZ#521244)

* a kernel panic when using bnx2x devices and LRO in a bridge. A warning is
now provided to disable LRO in these situations. (BZ#522636)

* the scsi_dh_rdac driver was updated to recognize the Sun StorageTek
Flexline 380. (BZ#523237)

* in FIPS mode, random number generators are required to not return the
first block of random data they generate, but rather save it to seed the
repetition check. This update brings the random number generator into
conformance. (BZ#523289)

* an option to disable/enable the use of the first random block is now
provided to bring ansi_cprng into compliance with FIPS-140 continuous test
requirements. (BZ#523290)

* running the SAP Linux Certification Suite in a KVM guest caused severe
SAP kernel errors, causing it to exit. (BZ#524150)

* attempting to 'online' a CPU for a KVM guest via sysfs caused a system
crash. (BZ#524151)

* when using KVM, pvclock returned bogus wallclock values. (BZ#524152)

* the clock could go backwards when using the vsyscall infrastructure.
(BZ#524527)

Users should upgrade to these updated packages, which contain backported
patches to correct these issues. The system must be rebooted for this
update to take effect.

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
http://kbase.redhat.com/faq/docs/DOC-11259

517967 - Bug in lockd prevents a locks being freed. [rhel-5.4.z]
517976 - [RHEL 5] sky2 eth0: receiver hang detected [rhel-5.4.z]
518132 - CVE-2009-2849 kernel: md: NULL pointer deref when accessing suspend_* sysfs attributes
519782 - [QLogic 5.5 bug] qla2xxx - allow use of MSI when MSI-X disabled. [rhel-5.4.z]
519783 - [QLogic 5.5 bug] qlge - fix hangs and read perfromance [rhel-5.4.z]
520685 - use KVM pvclock code to detect/correct lost ticks [rhel-5.4.z]
520686 - bare-metal and xen: /proc/cpuinfo does not list all CPU flags presented by CPU [rhel-5.4.z]
520905 - Serial ports don't function on 4838-310 without pnpacpi=off boot option [rhel-5.4.z]
520906 - mlx4_core fails to load on systems with32 cores [rhel-5.4.z]
520908 - TCP traffic for VLAN interfaces fails over mlx4_en parent interface. [rhel-5.4.z]
520919 - BUG: soft lockup - CPU#5 stuck for 10s at .context_struct_compute_av+0x214/0x39c [rhel-5.4.z]
521238 - [RHEL 5] Hang on boot due to wrong APIC timer calibration [rhel-5.4.z]
521239 - scsi_transport_fc: fc_user_scan can loop forever, needs mutex with rport list changes [rhel-5.4.z]
521241 - 5.4 alpha: Broadcom 5761 NIC does not work [rhel-5.4.z]
521244 - Read/Write NFS I/O performance degraded by FLUSH_STABLE page flushing [rhel-5.4.z]
522636 - bridge: Fix LRO crash with tun (tun_chr_read()) [rhel-5.4.z]
523237 - Add kernel (scsi_dh_rdac) support for Sun 6540 storage arrays. [rhel-5.4.z]
523289 - [FIP140-2] the first n- bit block generated after power-up, initialization, or reset shall not be used [rhel-5.4.z]
523290 - [FIPS140-2] Provide option to disable/enable use of the first random block [rhel-5.4.z]
524150 - Can't override KVM clock in a KVM guest with -165 kernel to triage SAP DB create failure [rhel-5.4.z]
524151 - cpu1 didn't come online in a kvm i686 guest [rhel-5.4.z]
524152 - pvclock return bogus wallclock values [rhel-5.4.z]
524527 - RHEV : SAP SLCS 2.3 fails during install/import in a RHEV-H/KVM guest with PV KVM clock [rhel-5.4.z]

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-2849
http://www.redhat.com/security/updates/classification/#moderate