An issue was discovered in the linux kernel's tty subsystem handling during shutdown. The flaw was possible to take a reference to the ldisc during shutdown phase. This race occurs on hangup of tty. It races and hangs on ldsem_down_write on a semaphore that is being aquired by a new reader(CPU 1). The new reader/writer is sleeping in ldsem_down_read() and the hangup is sleeping in ldsem_down_write(). Resources: Fix: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=cf872776fc84128bb779ce2b83a37c884c3203ae CVE request: http://seclists.org/oss-sec/2015/q2/545
Statement: This issue does not affect the Linux kernels as shipped with Red Hat Enterprise Linux 5, 6. This issue affects the Linux kernel packages kernel as shipped with Red Hat Enterprise Linux 7 and Red Hat Enterprise MRG 2.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2015:2411 https://rhn.redhat.com/errata/RHSA-2015-2411.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2015:2152 https://rhn.redhat.com/errata/RHSA-2015-2152.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.1 Extended Update Support Via RHSA-2016:1395 https://access.redhat.com/errata/RHSA-2016:1395