From: Kay Sievers <kay.sievers@vrfy.org>
Subject: Re: random bug generator (was: 2.6.21-git4 Scheduler, NOHZ, VFS
	bugs)
Date: Sat, 05 May 2007 20:07:07 +0200
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	 <20070504110158.d2808170.akpm@linux-foundation.org>
	 <6bffcb0e0705050625m6bb05dc0ne0864ec2dba19256@mail.gmail.com>
	 <463CC746.7050402@googlemail.com>
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Cc: Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@elte.hu>,
	Thomas Gleixner <tglx@linutronix.de>, viro@ftp.linux.org.uk,
	linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@suse.de>,
	Linus Torvalds <torvalds@linux-foundation.org>
To: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
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On Sat, 2007-05-05 at 20:04 +0200, Michal Piotrowski wrote:
> Hi,
>=20
> Michal Piotrowski napisa=C5=82(a):
> > On 04/05/07, Andrew Morton <akpm@linux-foundation.org> wrote:
> >> On Fri, 04 May 2007 18:20:51 +0200 Michal Piotrowski
> >> <michal.k.k.piotrowski@gmail.com> wrote:
> >>
> >> > I ran this script tree times,
> >> >
> >> > #! /bin/sh
> >> >
> >> > for i in `find /sys/ -type f`
> >> > do
> >> >     echo "wy=C5=9Bwietlam $i"
> >> >     sudo cat $i > /dev/null
> >> > done
> >> >
> >> > First run - scheduler bug
> >> > Second run - NOHZ bug
> >> > Third - VFS bug
> >> >
> >> > Hmmmm...
> >> >
> >> > [93298.252601] BUG: at /mnt/md0/devel/linux-git/kernel/sched.c:3=
241
> >> add_preempt_count()
> >> > [93298.260334]  [<c0105039>] show_trace_log_lvl+0x1a/0x2f
> >> > [93298.265507]  [<c0105720>] show_trace+0x12/0x14
> >> > [93298.269974]  [<c01057d2>] dump_stack+0x16/0x18
> >> > [93298.274434]  [<c011d18a>] add_preempt_count+0x89/0x8b
> >> > [93298.279501]  [<c0126492>] irq_enter+0xd/0x2e
> >> > [93298.283788]  [<c0114c1e>] smp_apic_timer_interrupt+0x2a/0x84
> >> > [93298.289458]  [<c0104b2b>] apic_timer_interrupt+0x33/0x38
> >> > [93298.294783]  [<c0257b79>] show_uevent+0x58/0xcd
> >> > [93298.299329]  =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D
> >> > [93390.468056] NOHZ: local_softirq_pending 22
> >> > [93447.105850] NOHZ: local_softirq_pending 22
> >> > [93450.332884] BUG: unable to handle kernel paging request at
> >> virtual address 3e343c0c
> >> > [93450.340626]  printing eip:
> >> > [93450.343333] c018e2bc
> >> > [93450.345520] *pde =3D 00000000
> >> > [93450.348314] Oops: 0000 [#1]
> >>
> >> Nice.  What was the last file which it read before crashing?
> >>
> >> Are you able to consistently crash it by reading just that file?
> >=20
> > Random files, random bugs (usually it starts with a slab corruption=
).
> >=20
> > git-bisect will give an answer.
>=20
> So this is a random bug generator...
>=20
> git-bisect bad
> 16574dccd8f62dc1b585325f8a6a0aab10047ed8 is first bad commit
> commit 16574dccd8f62dc1b585325f8a6a0aab10047ed8
> Author: Kay Sievers <kay.sievers@vrfy.org>
> Date:   Fri Apr 6 01:40:38 2007 +0200
>=20
>     Driver core: make uevent-environment available in uevent-file
>=20
>     This allows sysfs to show the environment variables that are avai=
lable
>     if the uevent happens.  This lets userspace not have to cache all=
 of
>     this information as the kernel already knows it.
>=20
>     Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
>     Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
>=20
> :040000 040000 34152258985968083c04ab003ced54d73e92a790 c3301e8cd7705=
c293817c6747b3cc59d6cbf14bb M      drivers
>=20
> http://www.stardust.webpages.pl/files/tbf/bitis-gabonica/2.6.21-git4/=
git-config

Greg fixed this:
  http://git.kernel.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;a=3D=
commitdiff;h=3Dc7308c81a8220ab68eebfadde37db881a2800064

Kay