CVE-2024-47736

/// Technical description

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

erofs: handle overlapped pclusters out of crafted images properly

syzbot reported a task hang issue due to a deadlock case where it is

waiting for the folio lock of a cached folio that will be used for

cache I/Os.

After looking into the crafted fuzzed image, I found it's formed with

several overlapped big pclusters as below:

Ext: logical offset | length : physical offset | length

0: 0.. 16384 | 16384 : 151552.. 167936 | 16384

1: 16384.. 32768 | 16384 : 155648.. 172032 | 16384

2: 32768.. 49152 | 16384 : 537223168.. 537239552 | 16384

...

Here, extent 0/1 are physically overlapped although it's entirely

_impossible_ for normal filesystem images generated by mkfs.

First, managed folios containing compressed data will be marked as

up-to-date and then unlocked immediately (unlike in-place folios) when

compressed I/Os are complete. If physical blocks

/// 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