control: forwarded -1 https://sourceware.org/bugzilla/show_bug.cgi?id=17980
On 2016-03-04 09:45, Markus Friedrich wrote: > Package: libc6 > Version: 2.21 > Severity: critical > Justification: breaks unrelated software > > Inter-process communication between a 64bit and a 32bit process is not > working. At least pthread named semaphores are not working. > A sem_wait is not awaken if a corresponding sem_post is done on the other > side, which generated a dead lock. > > This problem only exists if a 64bit process communicates with a 32bit > process but not for 32bit to 32bit communication or 64bit to 64bit > communication. This has been caused by a rewrite of the semaphore code: | commit 042e1521c794a945edc43b5bfa7e69ad70420524 | Author: Carlos O'Donell <car...@systemhalted.org> | Date: Wed Jan 21 00:46:16 2015 -0500 | | Fix semaphore destruction (bug 12674). | | This commit fixes semaphore destruction by either using 64b atomic | operations (where available), or by using two separate fields when only | 32b atomic operations are available. In the latter case, we keep a | conservative estimate of whether there are any waiting threads in one | bit of the field that counts the number of available tokens, thus | allowing sem_post to atomically both add a token and determine whether | it needs to call futex_wake. | | See: | https://sourceware.org/ml/libc-alpha/2014-12/msg00155.html For the full commit, see: https://sourceware.org/git/?p=glibc.git;a=commit;h=042e1521c794a945edc43b5bfa7e69ad70420524 It corresponds to upstream bug BZ 17980: https://sourceware.org/bugzilla/show_bug.cgi?id=17980 > Moreover Debian 8.3 and all other tested distributions have no problem with > 64bit to 32bit inter-process communication using pthread named semaphores. Given the issue is due to an upstream commit and not to a Debian specific change, all distributions with a glibc >= 2.21 are affected. Aurelien -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurel...@aurel32.net http://www.aurel32.net
