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From: "Woegerer, Paul" <Paul_Woegerer@mentor.com>
To: <openembedded-core@lists.openembedded.org>
Cc: Christopher Larson <chris_larson@mentor.com>,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: lttng-modules may trigger deadlock in the timekeeping subsystem with Linux <= 3.10.13, <= 3.11.2
Date: Mon, 14 Oct 2013 17:54:40 +0200	[thread overview]
Message-ID: <525C13C0.4020805@mentor.com> (raw)

Hi,

looking at the following commits shows that the current version of
lttng-modules 2.3.x can trigger a deadlock in the timekeeping subsystem
of Linux.

http://git.lttng.org/?p=lttng-modules.git;a=commit;h=fc8216ae9ec5d18172d8227d179475e7cc1fb45c
http://git.lttng.org/?p=lttng-modules.git;a=commit;h=9998f5216f4641a79e158135c4c1658dcc6cd2d8
http://git.lttng.org/?p=lttng-modules.git;a=commit;h=e14bf96416c39675a5f785b032d1c5279020b93d

This is caused by a bug in the kernel that was introduced in 3.10. The
problem is already fixed in Linux 3.10.14, 3.11.3 and 3.12. See:
http://marc.info/?l=linux-kernel&m=137894350929349

lttng-modules 2.3.2 contains preprocessor-code that makes sure that
building of lttng-modules fails for the unlucky combinations of kernel
and lttng-modules. The problem is when we update our lttng-modules 2.3.0
to 2.3.2 then we would have lttng-modules failing to build for our qemu*
MACHINEs.

Any recommendations on how we should address this ?

Many thanks,
Paul

-- 
Paul Woegerer, SW Development Engineer
Sourcery Analyzer <http://go.mentor.com/sourceryanalyzer>
Mentor Graphics, Embedded Software Division


             reply	other threads:[~2013-10-14 15:54 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-14 15:54 Woegerer, Paul [this message]
2013-10-14 16:32 ` lttng-modules may trigger deadlock in the timekeeping subsystem with Linux <= 3.10.13, <= 3.11.2 Tom Zanussi
2013-10-14 22:19   ` Tom Zanussi
2013-10-14 22:50   ` Bruce Ashfield
2013-10-15  6:59     ` Woegerer, Paul
2013-10-15  6:50   ` Woegerer, Paul

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