NULL Pointer Dereference The advisory has been revoked - it doesn't affect any version of package kernel-rt-debug-kvm  (opens in a new tab)


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0.03% (6th percentile)

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  • Snyk IDSNYK-CENTOS7-KERNELRTDEBUGKVM-10504304
  • published26 Jun 2025
  • disclosed18 Jun 2025

Introduced: 18 Jun 2025

CVE-2025-38059  (opens in a new tab)
CWE-476  (opens in a new tab)

Amendment

The Centos security team deemed this advisory irrelevant for Centos:7.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug-kvm package and not the kernel-rt-debug-kvm package as distributed by Centos.

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

btrfs: avoid NULL pointer dereference if no valid csum tree

[BUG] When trying read-only scrub on a btrfs with rescue=idatacsums mount option, it will crash with the following call trace:

BUG: kernel NULL pointer dereference, address: 0000000000000208 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page CPU: 1 UID: 0 PID: 835 Comm: btrfs Tainted: G O 6.15.0-rc3-custom+ #236 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:btrfs_lookup_csums_bitmap+0x49/0x480 [btrfs] Call Trace: <TASK> scrub_find_fill_first_stripe+0x35b/0x3d0 [btrfs] scrub_simple_mirror+0x175/0x290 [btrfs] scrub_stripe+0x5f7/0x6f0 [btrfs] scrub_chunk+0x9a/0x150 [btrfs] scrub_enumerate_chunks+0x333/0x660 [btrfs] btrfs_scrub_dev+0x23e/0x600 [btrfs] btrfs_ioctl+0x1dcf/0x2f80 [btrfs] __x64_sys_ioctl+0x97/0xc0 do_syscall_64+0x4f/0x120 entry_SYSCALL_64_after_hwframe+0x76/0x7e

[CAUSE] Mount option "rescue=idatacsums" will completely skip loading the csum tree, so that any data read will not find any data csum thus we will ignore data checksum verification.

Normally call sites utilizing csum tree will check the fs state flag NO_DATA_CSUMS bit, but unfortunately scrub does not check that bit at all.

This results in scrub to call btrfs_search_slot() on a NULL pointer and triggered above crash.

[FIX] Check both extent and csum tree root before doing any tree search.