On Wed, Oct 03, 2012 at 09:11:47AM +0200, Lukas Czerner wrote: > The result of the bit shift expression in > '1 << sbi->s_log_groups_per_flex' can be undefined in the case that > s_log_groups_per_flex is 31 because the result of the shift is bigger > than INT_MAX. In reality this probably should not cause much problems > since we'll end up with INT_MIN which will then be converted into > 'unsigned int' type, but nevertheless according to the ISO C99 the > result is actually undefined. > > Fix this by changing the left operand to 'unsigned int' type. > > Note that the commit d50f2ab6f050311dbf7b8f5501b25f0bf64a439b already > tried to fix the undefined behaviour, but this was missed. > > Thanks to Laszlo Ersek for pointing this out and suggesting the fix. > > Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx> > Reported-by: Laszlo Ersek <lersek@xxxxxxxxxx> > --- > fs/ext4/super.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 69c55d4..95b9c8e 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -1929,7 +1929,7 @@ static int ext4_fill_flex_info(struct super_block *sb) > sbi->s_log_groups_per_flex = 0; > return 1; > } > - groups_per_flex = 1 << sbi->s_log_groups_per_flex; > + groups_per_flex = 1U << sbi->s_log_groups_per_flex; > > /* We allocate both existing and potentially added groups */ > flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) + Looks good, Reviewed-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx> -- --Carlos -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
