CVE-2024-50280dm cache: fix flushing uninitialized delayed_work on cache_ctr error

Official description

In the Linux kernel, the following vulnerability has been resolved: dm cache: fix flushing uninitialized delayed_work on cache_ctr error An unexpected WARN_ON from flush_work() may occur when cache creation fails, caused by destroying the uninitialized delayed_work waker in the error path of cache_create(). For example, the warning appears on the superblock checksum error. Reproduce steps: dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dd if=/dev/urandom of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" Kernel logs: (snip) WARNING: CPU: 0 PID: 84 at kernel/workqueue.c:4178 __flush_work+0x5d4/0x890 Fix by pulling out the cancel_delayed_work_sync() from the constructor's error path. This patch doesn't affect the use-after-free fix for concurrent dm_resume and dm_destroy (commit 6a459d8edbdb ("dm cache: Fix UAF in destroy()")) as cache_dtr is not changed.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/40fac0271c7aedf60d81ed8214e80851e5b26312
• https://git.kernel.org/stable/c/d154b333a5667b6c1b213a11a41ad7aaccd10c3d
• https://git.kernel.org/stable/c/5a754d3c771280f2d06bf8ab716d6a0d36ca256e
• https://git.kernel.org/stable/c/8cc12dab635333c4ea28e72d7b947be7d0543c2c
• https://git.kernel.org/stable/c/aee3ecda73ce13af7c3e556383342b57e6bd0718
• https://git.kernel.org/stable/c/135496c208ba26fd68cdef10b64ed7a91ac9a7ff
• https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
• https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html