linux-kernel - Re: next-20090310: ext4 hangs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 26 Mar 2009 01:25:55 +0100
From:	Jan Kara <jack@...e.cz>
To:	Jiri Gaisler <jiri@...sler.com>
Cc:	Alexander Beregalov <a.beregalov@...il.com>,
	Theodore Tso <tytso@....edu>,
	"linux-next@...r.kernel.org" <linux-next@...r.kernel.org>,
	linux-ext4@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	sparclinux@...r.kernel.org
Subject: Re: next-20090310: ext4 hangs

On Thu 26-03-09 01:17:06, Jiri Gaisler wrote:
> Jan Kara wrote:
> >   Hi,
> > 
> >   thanks for the updated disassembly.
> > 
> >>   55bab0:       82 10 60 01     or  %g1, 1, %g1
> >>                 spin_unlock(&journal->j_list_lock);
> >>   55bab4:       40 06 4b 20     call  6ee734 <_spin_unlock>
> >>   55bab8:       c2 24 e0 28     st  %g1, [ %l3 + 0x28 ]
> >   OK, so it really seems that:
> >   jinode->i_flags |= JI_COMMIT_RUNNING;
> >   spin_unlock(&journal->j_list_lock);
> > 
> >   has been compiled to
> >   ld [ %l3 + 0x28 ], %g1
> >   or  %g1, 1, %g1
> >   call  6ee734 <_spin_unlock>
> >   st  %g1, [ %l3 + 0x28 ]
> > 
> >   Which seems like a bug in the compiler or in the way implement compiler
> > barriers in spin_unlock() on UP sparc. Or is there some sparc magic by which
> > this is correct code? Any clever sparc guy?
> > 
> Looks fine to me - the store is made in the branch delay slot
> of the call, so it will occur before the first instruction at
> the call target address executes.
  Thanks for explanation. I knew sparc had some surprising features like
this ;).
								Honza
-- 
Jan Kara <jack@...e.cz>
SUSE Labs, CR
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/