CVE-2025-21778

/// Technical description

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

tracing: Do not allow mmap() of persistent ring buffer

When trying to mmap a trace instance buffer that is attached to

reserve_mem, it would crash:

BUG: unable to handle page fault for address: ffffe97bd00025c8

#PF: supervisor read access in kernel mode

#PF: error_code(0x0000) - not-present page

PGD 2862f3067 P4D 2862f3067 PUD 0

Oops: Oops: 0000 [#1] PREEMPT_RT SMP PTI

CPU: 4 UID: 0 PID: 981 Comm: mmap-rb Not tainted 6.14.0-rc2-test-00003-g7f1a5e3fbf9e-dirty #233

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014

RIP: 0010:validate_page_before_insert+0x5/0xb0

Code: e2 01 89 d0 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 <48> 8b 46 08 a8 01 75 67 66 90 48 89 f0 8b 50 34 85 d2 74 76 48 89

RSP: 0018:ffffb148c2f3f968 EFLAGS: 00010246

RAX: ffff9fa5d3322000 RBX: ffff9fa5ccff9c08 RCX: 00000000b879ed29

R

/// 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