Date: Mon, 3 Nov 2008 12:26:42 -0500 From: Jung-uk Kim <jkim@FreeBSD.org> To: Alexander Motin <mav@FreeBSD.org> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r184558 - head/sys/dev/acpica/Osd Message-ID: <200811031226.46956.jkim@FreeBSD.org> In-Reply-To: <490F21FC.1020508@FreeBSD.org> References: <200811021250.mA2CoGs1038957@svn.freebsd.org> <200811031050.48765.jkim@FreeBSD.org> <490F21FC.1020508@FreeBSD.org>
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On Monday 03 November 2008 11:08 am, Alexander Motin wrote: > Jung-uk Kim wrote: > > On Sunday 02 November 2008 07:50 am, Alexander Motin wrote: > >> Author: mav > >> Date: Sun Nov 2 12:50:16 2008 > >> New Revision: 184558 > >> URL: http://svn.freebsd.org/changeset/base/184558 > >> > >> Log: > >> As soon as we have several threads per process now, it is not > >> correct to use process ID as ACPI thread ID. Concurrent requests > >> with equal thread IDs broke ACPI mutexes operation causing > >> unpredictable errors including AE_AML_MUTEX_NOT_ACQUIRED that I > >> have seen. > >> > >> Use kernel thread ID instead of process ID for ACPI thread. > > > > Sorry but this patch is incorrect, i.e., td_tid is not unique. > > You have to use curthread or (p_pid, td_tid) pair. > > Unfortunately, even if you correct this problem, you also have to > > correct ACPI_THREAD_ID definition, which is in the vendor code. > > That's why it wasn't done yet and it is more complicated than you > > think, i.e., ACPI-CA assumes sizeof(ACPI_THREAD_ID) == > > sizeof(int), etc. Please see the related ACPI-CA bugs: > > I'm also sorry, but that is what I see: > typedef __int32_t __lwpid_t; /* Thread ID (a.k.a. LWP) > */ ... > td->td_tid = alloc_unr(tid_unrhdr); > ... > tid_unrhdr = new_unrhdr(PID_MAX + 2, INT_MAX, &tid_lock); > > So what have I missed, where is the problem? Why td_tid is not > unique and where is the size problem? On top of that: /* Returning 0 is not allowed. */ return (curthread->td_tid + 1); may actually return 0 because it can be INT_MAX. :-) Jung-uk Kim
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