Messages in this thread | | | Date | Fri, 21 Jul 2023 20:56:00 +0530 | From | Ritesh Harjani (IBM) <> | Subject | Re: [PATCH 02/10] ext4: avoid potential data overflow in next_linear_group |
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Kemeng Shi <shikemeng@huaweicloud.com> writes:
> ngroups is ext4_group_t (unsigned int) while next_linear_group treat it > in int. If ngroups is bigger than max number described by int, it will > be treat as a negative number. Then "return group + 1 >= ngroups ? 0 : > group + 1;" may keep returning 0. > Switch int to ext4_group_t in next_linear_group to fix the overflow. >
Fixes: 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning")
With that feel free to add: Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> > --- > fs/ext4/mballoc.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 90ffabac100b..33ee3991f62c 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -1081,8 +1081,9 @@ static inline int should_optimize_scan(struct ext4_allocation_context *ac) > * Return next linear group for allocation. If linear traversal should not be > * performed, this function just returns the same group > */ > -static int > -next_linear_group(struct ext4_allocation_context *ac, int group, int ngroups) > +static ext4_group_t > +next_linear_group(struct ext4_allocation_context *ac, ext4_group_t group, > + ext4_group_t ngroups) > { > if (!should_optimize_scan(ac)) > goto inc_and_return; > -- > 2.30.0
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