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From: Markus Trippelsdorf <markus@trippelsdorf.de>
To: Jakub Jelinek <jakub@redhat.com>
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	"Michel Dänzer" <michel@daenzer.net>,
	"Linus Torvalds" <torvalds@linux-foundation.org>
Subject: Re: [PATCH 3.15 33/37] Fix gcc-4.9.0 miscompilation of load_balance()  in scheduler
Date: Wed, 30 Jul 2014 09:27:47 +0200	[thread overview]
Message-ID: <20140730072747.GG22904@x4> (raw)
In-Reply-To: <20140730072120.GB1652@laptop.redhat.com>

On 2014.07.30 at 09:21 +0200, Jakub Jelinek wrote:
> On Wed, Jul 30, 2014 at 09:13:08AM +0200, Markus Trippelsdorf wrote:
> > On 2014.07.30 at 08:53 +0200, Jakub Jelinek wrote:
> > > On Tue, Jul 29, 2014 at 06:49:09PM -0700, Greg Kroah-Hartman wrote:
> > > > 3.15-stable review patch.  If anyone has any objections, please let me know.
> > > 
> > > IMNSHO this is a too big hammer approach.  The bug happened on a single
> > > file only (right?), so if anything, IMHO it could be disabled for that
> > > single file only, and better do it only for compilers with the bug.
> > 
> > No. There are many more files affected. It just happens that Linus
> > analyzed the assembly of this single file (fair.c) and found a bug. 
> > Just build your redhat distro kernel with GCC_COMPARE_DEBUG=1 and you'll
> > see. So unless someone analyzes the assembly output of all other
> > affected files by hand and finds no issues, one has to assume the worst.
> 
> I'm talking about wrong-code issues.  For -fcompare-debug, we indeed check
> it primarily during gcc bootstrap (through bootstrap-debug) and some
> testcases, and we'll certainly try to build some more code with
> -fcompare-debug and fix the issues.

Yes, I'm talking about wrong-code issues, too. For example the pr61801.c
testcase was reduced from kernel/exit.c.

-- 
Markus

  reply	other threads:[~2014-07-30  7:27 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-30  1:48 [PATCH 3.15 00/37] 3.15.8-stable review Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 01/37] media: staging: tighten omap4iss dependencies Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 02/37] media: media: v4l2-core: v4l2-dv-timings.c: Cleaning up code wrong value used in aspect ratio Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 03/37] media: af9035: override tuner id when bad value set into eeprom Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 04/37] media: hdpvr: fix two audio bugs Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 05/37] media: tda10071: force modulation to QPSK on DVB-S Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 06/37] nfs: only show Posix ACLs in listxattr if actually present Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 07/37] xtensa: fix sysmem reservation at the end of existing block Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 08/37] block: provide compat ioctl for BLKZEROOUT Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 09/37] block: dont assume last put of shared tags is for the host Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 10/37] libata: support the ata host which implements a queue depth less than 32 Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 11/37] libata: introduce ata_host->n_tags to avoid oops on SAS controllers Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 12/37] s390/ptrace: fix PSW mask check Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 13/37] ahci: add support for the Promise FastTrak TX8660 SATA HBA (ahci mode) Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 14/37] blkcg: dont call into policy draining if root_blkg is already gone Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 15/37] tracing: Fix wraparound problems in "uptime" trace clock Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 16/37] zram: avoid lockdep splat by revalidate_disk Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 17/37] powerpc/pseries: dynamically added OF nodes need to call of_node_init Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 18/37] slab_common: fix the check for duplicate slab names Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 19/37] Input: synaptics - add min/max quirk for pnp-id LEN2002 (Edge E531) Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 20/37] Input: fix defuzzing logic Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 21/37] coredump: fix the setting of PF_DUMPCORE Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 22/37] fuse: s_time_gran fix Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 23/37] fuse: add FUSE_NO_OPEN_SUPPORT flag to INIT Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 24/37] pinctrl: st: Fix irqmux handler Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 25/37] parisc: Remove SA_RESTORER define Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 26/37] hwmon: (smsc47m192) Fix temperature limit and vrm write operations Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 27/37] parport: fix menu breakage Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 28/37] fs: umount on symlink leaks mnt count Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 29/37] x86_32, entry: Store badsys error code in %eax Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 32/37] mm: hugetlb: fix copy_hugetlb_page_range() Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 34/37] hwrng: virtio - ensure reads happen after successful probe Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 35/37] mm: do not call do_fault_around for non-linear fault Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 36/37] nl80211: move set_qos_map command into split state Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 37/37] platform_get_irq: Revert to platform_get_resource if of_irq_get fails Greg Kroah-Hartman
     [not found] ` <20140730014829.344302554@linuxfoundation.org>
2014-07-30  6:53   ` [PATCH 3.15 33/37] Fix gcc-4.9.0 miscompilation of load_balance() in scheduler Jakub Jelinek
2014-07-30  7:13     ` Markus Trippelsdorf
2014-07-30  7:21       ` Jakub Jelinek
2014-07-30  7:27         ` Markus Trippelsdorf [this message]
2014-07-30 15:47     ` Linus Torvalds
2014-08-05 11:31       ` Josh Boyer
2014-08-05 11:46         ` Markus Trippelsdorf
2014-08-05 15:24           ` Jakub Jelinek
2014-08-05 15:19         ` Greg Kroah-Hartman
2014-08-05 16:49         ` Linus Torvalds
2014-08-05 20:57           ` Josh Boyer
2014-08-05 21:07             ` Frank Ch. Eigler
2014-08-05 22:36               ` Linus Torvalds
2014-08-05 23:30                 ` Frank Ch. Eigler
2014-08-05 23:59                   ` Linus Torvalds
2014-08-06  8:14                 ` Jakub Jelinek
2014-08-06 10:23                   ` Måns Rullgård
2014-08-06 16:34                   ` Alexei Starovoitov
2014-07-30 11:58 ` [PATCH 3.15 00/37] 3.15.8-stable review Satoru Takeuchi
2014-07-30 15:50   ` Greg Kroah-Hartman
2014-07-30 16:09 ` Guenter Roeck
2014-07-30 22:23   ` Greg Kroah-Hartman

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