CVE-2024-56755: In the Linux kernel, the following vulnerability has been resolved: netfs/fscache: Add a memory barrier for FSCACHE_VOLUME_CREATING In fscache_creat...

Description

In the Linux kernel, the following vulnerability has been resolved: netfs/fscache: Add a memory barrier for FSCACHE_VOLUME_CREATING In fscache_create_volume(), there is a missing memory barrier between the bit-clearing operation and the wake-up operation. This may cause a situation where, after a wake-up, the bit-clearing operation hasn't been detected yet, leading to an indefinite wait. The triggering process is as follows: [cookie1] [cookie2] [volume_work] fscache_perform_lookup fscache_create_volume fscache_perform_lookup fscache_create_volume fscache_create_volume_work cachefiles_acquire_volume clear_and_wake_up_bit test_and_set_bit test_and_set_bit goto maybe_wait goto no_wait In the above process, cookie1 and cookie2 has the same volume. When cookie1 enters the -no_wait- process, it will clear the bit and wake up the waiting process. If a barrier is missing, it may cause cookie2 to remain in the -wait- process indefinitely. In commit 3288666c7256 ("fscache: Use clear_and_wake_up_bit() in fscache_create_volume_work()"), barriers were added to similar operations in fscache_create_volume_work(), but fscache_create_volume() was missed. By combining the clear and wake operations into clear_and_wake_up_bit() to fix this issue.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.20%

10.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	>= 5.17, < 6.1.120
Linux	Linux Kernel	>= 6.2, < 6.6.64
Linux	Linux Kernel	>= 6.7, < 6.11.11
Linux	Linux Kernel	>= 6.12, < 6.12.2

References

Timeline

Published: Dec 29, 2024
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2024-56755?

In the Linux kernel, the following vulnerability has been resolved: netfs/fscache: Add a memory barrier for FSCACHE_VOLUME_CREATING In fscache_create_volume(), there is a missing memory barrier between the bit-clearing operation and the wake-up operation. This may cause a situation where, after a wake-up, the bit-clearing operation hasn't been detected yet, leading to an indefinite wait. The triggering process is as follows: [cookie1] [cookie2] [volume_work] fscache_perform_lookup fscache_create_volume fscache_perform_lookup fscache_create_volume fscache_create_volume_work cachefiles_acquire_volume clear_and_wake_up_bit test_and_set_bit test_and_set_bit goto maybe_wait goto no_wait In the above process, cookie1 and cookie2 has the same volume. When cookie1 enters the -no_wait- process, it will clear the bit and wake up the waiting process. If a barrier is missing, it may cause cookie2 to remain in the -wait- process indefinitely. In commit 3288666c7256 ("fscache: Use clear_and_wake_up_bit() in fscache_create_volume_work()"), barriers were added to similar operations in fscache_create_volume_work(), but fscache_create_volume() was missed. By combining the clear and wake operations into clear_and_wake_up_bit() to fix this issue.

How severe is CVE-2024-56755?

CVE-2024-56755 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2024-56755?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.