From: Al Viro <viro@ZenIV.linux.org.uk>
To: Larry Finger <Larry.Finger@lwfinger.net>
Cc: LKML <linux-kernel@vger.kernel.org>,
Thorsten Leemhuis <regressions@leemhuis.info>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: Regression in kernel 4.12-rc1 for Powerpc 32 - bisected to commit 3448890c32c3
Date: Sun, 25 Jun 2017 12:14:04 +0100 [thread overview]
Message-ID: <20170625111404.GV10672@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20170625095351.GU10672@ZenIV.linux.org.uk>
On Sun, Jun 25, 2017 at 10:53:58AM +0100, Al Viro wrote:
> On Sat, Jun 24, 2017 at 12:29:23PM -0500, Larry Finger wrote:
>
> > I made a break through. If I turn off inline copy to/from users for 32-bit
> > ppc with the following patch, then the system boots:
>
> OK... So it's 4.6.3 miscompiling something - it is hardware-independent,
> reproduced in qemu. I'd like to get more self-contained example of
> miscompile, though; should be done by tonight...
OK, it's the call in rw_copy_check_uvector(); with INLINE_COPY_FROM_USER
it's miscompiled by 4.6.3. I hadn't looked through the generated code
yet; will do that after I grab some sleep.
next prev parent reply other threads:[~2017-06-25 11:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <69187aa4-611f-b08a-8d14-b8fa47b4c464@lwfinger.net>
[not found] ` <1588557c-2706-0c0e-3387-4ae65d0b5790@lwfinger.net>
[not found] ` <20170621212257.GN10672@ZenIV.linux.org.uk>
[not found] ` <5f4b9fa4-262a-31b1-32ba-a2f6e789b3d6@lwfinger.net>
[not found] ` <20170621213415.GO10672@ZenIV.linux.org.uk>
[not found] ` <655d304e-e455-6e0c-56e1-f127653ea13c@lwfinger.net>
[not found] ` <20170622141203.GP10672@ZenIV.linux.org.uk>
[not found] ` <7bbd4c87-e8ff-5f83-8c4c-e205872083bf@lwfinger.net>
[not found] ` <20170622192515.GQ10672@ZenIV.linux.org.uk>
[not found] ` <2346c306-8e26-94cb-3c63-b866a7f4625d@lwfinger.net>
2017-06-23 20:29 ` Regression in kernel 4.12-rc1 for Powerpc 32 - bisected to commit 3448890c32c3 Al Viro
2017-06-24 0:04 ` Larry Finger
2017-06-24 17:29 ` Larry Finger
2017-06-25 9:53 ` Al Viro
2017-06-25 11:14 ` Al Viro [this message]
2017-06-25 20:53 ` gcc 4.6.3 miscompile on ppc32 (was Re: Regression in kernel 4.12-rc1 for Powerpc 32 - bisected to commit 3448890c32c3) Al Viro
2017-06-25 21:44 ` Segher Boessenkool
2017-06-25 22:21 ` Al Viro
2017-06-26 13:37 ` Michael Ellerman
2017-06-26 13:40 ` Regression in kernel 4.12-rc1 for Powerpc 32 - bisected to commit 3448890c32c3 Michael Ellerman
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