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 nilfs_evict_inode() or nilfs_dirty_inode(). And these can cause a deadlock if they are called while nilfs->ns_segctor_sem is held: Fix this issue by dropping the __GFP_FS flag from the page cache GFP flags of newly created symlinks in the same way that nilfs_new_inode() and __nilfs_read_inode() do, as a workaround until we adopt nofs allocation scope consistently or improve the locking constraints.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
21fc61c73c3903c4c312d0802da01ec2b323d174 to < cc38c596e648575ce58bfc31623a6506eda4b94aaffected21fc61c73c3903c4c312d0802da01ec2b323d174 to < a1686db1e59f8fc016c4c9361e2119dd206f479aaffected21fc61c73c3903c4c312d0802da01ec2b323d174 to < c72e0df0b56c1166736dc8eb62070ebb12591447affected21fc61c73c3903c4c312d0802da01ec2b323d174 to < 69548bb663fcb63f9ee0301be808a36b9d78dac3affected21fc61c73c3903c4c312d0802da01ec2b323d174 to < 58c7f44c7b9e5ac7e3b1e5da2572ed7767a12f38affected21fc61c73c3903c4c312d0802da01ec2b323d174 to < 1246d86e7bbde265761932c6e2dce28c69cdcb91affected21fc61c73c3903c4c312d0802da01ec2b323d174 to < 9aa5d43ac4cace8fb9bd964ff6c23f599dc3cd24affected21fc61c73c3903c4c312d0802da01ec2b323d174 to < b3a033e3ecd3471248d474ef263aadc0059e516aaffected076e4ab3279eb3ddb206de44d04df7aeb2428e09affected4.4.116 to < 4.5affected
Linux Linux
Default version status: affected
4.5affected0 to < 4.5unaffected4.19.323 to ≤ 4.19.*unaffected5.4.285 to ≤ 5.4.*unaffected5.10.229 to ≤ 5.10.*unaffected5.15.171 to ≤ 5.15.*unaffected6.1.116 to ≤ 6.1.*unaffected6.6.60 to ≤ 6.6.*unaffected6.11.7 to ≤ 6.11.*unaffected6.12 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/cc38c596e648575ce58bfc31623a6506eda4b94a ↗
- https://git.kernel.org/stable/c/a1686db1e59f8fc016c4c9361e2119dd206f479a ↗
- https://git.kernel.org/stable/c/c72e0df0b56c1166736dc8eb62070ebb12591447 ↗
- https://git.kernel.org/stable/c/69548bb663fcb63f9ee0301be808a36b9d78dac3 ↗
- https://git.kernel.org/stable/c/58c7f44c7b9e5ac7e3b1e5da2572ed7767a12f38 ↗
- https://git.kernel.org/stable/c/1246d86e7bbde265761932c6e2dce28c69cdcb91 ↗
- https://git.kernel.org/stable/c/9aa5d43ac4cace8fb9bd964ff6c23f599dc3cd24 ↗
- https://git.kernel.org/stable/c/b3a033e3ecd3471248d474ef263aadc0059e516a ↗
- https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html ↗
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html ↗