5.15-stable review patch. If anyone has any objections, please let me know.
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From: Kemeng Shi shikemeng@huaweicloud.com
[ Upstream commit 60c672b7f2d1e5dd1774f2399b355c9314e709f8 ]
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") Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Reviewed-by: Ritesh Harjani (IBM) ritesh.list@gmail.com Link: https://lore.kernel.org/r/20230801143204.2284343-3-shikemeng@huaweicloud.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- 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 c52833d07602c..7e7153c673c0d 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1011,8 +1011,9 @@ 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;