Date: Wed, 21 Mar 2012 13:41:03 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r233249 - head/sys/amd64/acpica Message-ID: <201203211341.11859.jkim@FreeBSD.org> In-Reply-To: <20120321100722.GP2358@deviant.kiev.zoral.com.ua> References: <201203202037.q2KKbNfK037014@svn.freebsd.org> <20120321100722.GP2358@deviant.kiev.zoral.com.ua>
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On Wednesday 21 March 2012 06:07 am, Konstantin Belousov wrote: > On Tue, Mar 20, 2012 at 08:37:23PM +0000, Jung-uk Kim wrote: > > Author: jkim > > Date: Tue Mar 20 20:37:23 2012 > > New Revision: 233249 > > URL: http://svn.freebsd.org/changeset/base/233249 > > > > Log: > > Fix another witness panic. We cannot enter critical section at > > all because AcpiEnterSleepState() executes (optional) _GTS method > > since ACPICA 20120215 (r231844). To evaluate the method, we need > > malloc(9), which may sleep. > > You papered over the issue, and not fixed it. Yes, it is a stopgap. > If sleep may happen, as it is for malloc, you cannot sleep with > interrupts turned off. This would cause a deadlock at best. I am well aware of the problem. In fact, that's why I had to merge ACPICA 20120320 rather quickly, which added a new flag to not execute _GTS method. Both _GTS and _BFS are turned off by default. You can control them with a new tunable "debug.acpi.sleep_flags" if you want. Please see the updated acpi(4). Jung-uk Kim
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