Integer truncation in fs/xfs/libxfs/xfs_da_btree.c

[Kristian]

Hello,

there is an integer truncation in

fs/xfs/libxfs/xfs_da_btree.c +2081

/* account for newly allocated blocks in reserved blocks total */
args->total -= dp->i_d.di_nblocks - nblks;

with the types: uint32 -= uint64 - uint64

On a hardened kernel with grsecurity enabled, this leads to a fault.

https://forums.grsecurity.net/viewtopic.php?f=3&t=4346&sid=3200600c0faaab4bf8779a95c549a737

Is this intentional and safe?

Regards

Kristian