CVE-2023-53149

/// Technical description

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

ext4: avoid deadlock in fs reclaim with page writeback

Ext4 has a filesystem wide lock protecting ext4_writepages() calls to

avoid races with switching of journalled data flag or inode format. This

lock can however cause a deadlock like:

CPU0 CPU1

ext4_writepages()

percpu_down_read(sbi->s_writepages_rwsem);

ext4_change_inode_journal_flag()

percpu_down_write(sbi->s_writepages_rwsem);

- blocks, all readers block from now on

ext4_do_writepages()

ext4_init_io_end()

kmem_cache_zalloc(io_end_cachep, GFP_KERNEL)

fs_reclaim frees dentry...

dentry_unlink_inode()

iput() - last ref =>

iput_final() - inode dirty =>

write_inode_now()...

ext4_writepages() tries to acquire sbi->s_writepages_rwsem

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References