CVE-2024-50229

/// Technical description

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

nilfs2: fix potential deadlock with newly created symlinks

Syzbot reported that page_symlink(), called by nilfs_symlink(), triggers

memory reclamation involving the filesystem layer, which can result in

circular lock dependencies among the reader/writer semaphore

nilfs->ns_segctor_sem, s_writers percpu_rwsem (intwrite) and the

fs_reclaim pseudo lock.

This is because after commit 21fc61c73c39 ("don't put symlink bodies in

pagecache into highmem"), the gfp flags of the page cache for symbolic

links are overwritten to GFP_KERNEL via inode_nohighmem().

This is not a problem for symlinks read from the backing device, because

the __GFP_FS flag is dropped after inode_nohighmem() is called. However,

when a new symlink is created with nilfs_symlink(), the gfp flags remain

overwritten to GFP_KERNEL. Then, memory allocation called from

page_symlink() etc. triggers memory reclamation including the FS layer,

which may call n

/// 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