linux-ext4 - Re: [OOPs] ext4: fixpoint divide exception at ext4_fill

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Message-ID: <4AF17638.7010105@linux.vnet.ibm.com>
Date:	Wed, 04 Nov 2009 18:10:24 +0530
From:	Nageswara R Sastry <rnsastry@...ux.vnet.ibm.com>
To:	linux-ext4 <linux-ext4@...r.kernel.org>
CC:	Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>,
	sachin p sant <sachinp@...ux.vnet.ibm.com>,
	Ramon <rcvalle@...ux.vnet.ibm.com>
Subject: Re: [OOPs] ext4: fixpoint divide exception at ext4_fill_super+0x141c/0x2908

Hi,

The following bug exists in 2.6.32-rc* also.

 > ------------[ cut here ]------------
 > Kernel BUG at 000003e00429d934 [verbose debug info unavailable]
 > fixpoint divide exception: 0009 [#1] SMP

Please find the patch which solves the following 'fixpoint divide 
exception'. I tested the same and not seeing any KERNEL BUG/exception.

I created the patch from 2.6.32-rc6 code.

Thanks and Regards
R.Nageswara Sastry

Though the 'sbi->s_log_groups_per_flex' contains valid data after the 
shift operation 'groups_per_flex' is becoming zero, which later used as 
a divisor.
groups_per_flex = 1 << sbi->s_log_groups_per_flex

Signed-off-by: Nageswara R Sastry <rnsastry@...ux.vnet.ibm.com>

View attachment "ext4_fix_point_division_error.patch" of type "text/plain" (814 bytes)