CVE-2025-38580

In the Linux kernel, the following vulnerability has been resolved:

ext4: fix inode use after free in ext4_end_io_rsv_work()

In ext4_io_end_defer_completion(), check if io_end->list_vec is empty to avoid adding an io_end that requires no conversion to the i_rsv_conversion_list, which in turn prevents starting an unnecessary worker. An ext4_emergency_state() check is also added to avoid attempting to abort the journal in an emergency state.

Additionally, ext4_put_io_end_defer() is refactored to call ext4_io_end_defer_completion() directly instead of being open-coded. This also prevents starting an unnecessary worker when EXT4_IO_END_FAILED is set but data_err=abort is not enabled.

This ensures that the check in ext4_put_io_end_defer() is consistent with the check in ext4_end_bio(). Otherwise, we might add an io_end to the i_rsv_conversion_list and then call ext4_finish_bio(), after which the inode could be freed before ext4_end_io_rsv_work() is called, triggering a use-after-free issue.

This vulnerability does not impact Red Hat Enterprise Linux as the regressive code change is not present in Red Hat kernels. The flaw stems from improper handling of deferred completion queues within the ext4 file system, creating an asynchronous race condition that could trigger memory corruption or a system crash when handling file system errors. Because the vulnerable commit was introduced in newer upstream releases, supported Red Hat platforms remain unaffected.