2026-01-13 15:31:26
Linux
PUBLISHED
In the Linux kernel, the following vulnerability has been resolved: shmem: fix recovery on rename failures maple_tree insertions can fail if we are seriously short on memory; simple_offset_rename() does not recover well if it runs into that. The same goes for simple_offset_rename_exchange(). Moreover, shmem_whiteout() expects that if it succeeds, the caller will progress to d_move(), i.e. that shmem_rename2() wont fail past the successful call of shmem_whiteout(). Not hard to fix, fortunately - mtree_store() cant fail if the index we are trying to store into is already present in the tree as a singleton. For simple_offset_rename_exchange() thats enough - we just need to be careful about the order of operations. For simple_offset_rename() solution is to preinsert the target into the tree for new_dir; the rest can be done without any potentially failing operations. That preinsertion has to be done in shmem_rename2() rather than in simple_offset_rename() itself - otherwise wed need to deal with the possibility of failure after successful shmem_whiteout().