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From: David Miller <davem@davemloft.net>
To: torvalds@linux-foundation.org
Cc: tony.luck@intel.com, walken@google.com, dhowells@redhat.com,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: tasks getting stuck on mmap_sem?
Date: Tue, 17 Aug 2010 16:40:13 -0700 (PDT)	[thread overview]
Message-ID: <20100817.164013.193700583.davem@davemloft.net> (raw)
In-Reply-To: <AANLkTikcaVKnJxC18tUcJRTQwAukYhPdWMgGGrNaVjM_@mail.gmail.com>

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 17 Aug 2010 14:28:49 -0700

> Oh, and it strikes me when looking at the sparc rwsem-const.h that it
> has some unsigned constants in it. I think
> 
>   #define RWSEM_WAITING_BIAS              0xffff0000
> 
> is actually unsigned, because it's a hex constant that doesn't fit in
> a signed int. So it's of type 'unsigned int' if I recall the C type
> rules right.

You were right all along, of course.  Nice spotting.

Something was messed up with my testing methodology last night such
that I didn't test the revert of the lib/rwsem.c changes properly.
Those actually did in fact introduce the problem.

And fixing these sparc rwsem values to be signed constants fixes the bug.

Thanks guys.

  parent reply	other threads:[~2010-08-17 23:39 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-17  4:12 tasks getting stuck on mmap_sem? David Miller
2010-08-17 16:14 ` Linus Torvalds
2010-08-17 18:24   ` Tony Luck
2010-08-17 20:46     ` Tony Luck
2010-08-17 21:08       ` Linus Torvalds
2010-08-17 21:26         ` Tony Luck
2010-08-17 21:28         ` Linus Torvalds
2010-08-17 21:47           ` Michel Lespinasse
2010-08-17 21:59             ` David Miller
2010-08-17 23:40           ` David Miller [this message]
2010-08-17 21:44     ` David Miller
  -- strict thread matches above, loose matches on Subject: below --
2010-08-17  5:22 Dimitris Michailidis
2010-08-17  5:35 ` David Miller
2010-08-17  7:23 ` David Miller

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