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@xxxxxxxxxxxxxxxxxx>
diff -Naurp a/linux-2.6.32-rc6/fs/ext4/super.c b/linux-2.6.32-rc6/fs/ext4/super.c
--- a/linux-2.6.32-rc6/fs/ext4/super.c 2009-11-03 20:37:49.000000000 +0100
+++ b/linux-2.6.32-rc6/fs/ext4/super.c 2009-11-04 13:21:48.000000000 +0100
@@ -1681,6 +1681,12 @@ static int ext4_fill_flex_info(struct su
sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
groups_per_flex = 1 << sbi->s_log_groups_per_flex;
+ /* There are some situations, after shift the value of 'groups_per_flex'
+ can become zero and division with 0 will result in fixpoint divide exception
+ */
+ if (groups_per_flex == 0)
+ return 1;
+
/* We allocate both existing and potentially added groups */
flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
((le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) + 1) <<
