null_blk: use DEFINE_MUTEX for the file-scope mutex

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-90190
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 17:17:13 UTC
Updated2026-09-17 17:17:13 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: null_blk: use DEFINE_MUTEX for the file-scope mutex In null_init(), mutex_init(&lock) currently happens after configfs_register_subsystem(), which exposes the nullb subsystem to userspace. A racing mkdir() into /sys/kernel/config/nullb/ can reach null_find_dev_by_name() -> mutex_lock(&lock) before the mutex is initialized, trigger warning: [ 123.137788] DEBUG_LOCKS_WARN_ON(lock->magic != lock) [ 123.137796] WARNING: kernel/locking/mutex.c:159 at mutex_lock+0x171/0x1c0, CPU#13: mkdir/1301 [ 123.140090] Modules linked in: null_blk(+) nft_fib_inet nft_fib_ipv4 ...... [ 123.154926] Call Trace: [ 123.155172] <TASK> [ 123.155419] ? __pfx_mutex_lock+0x10/0x10 [ 123.156181] ? __pfx__raw_spin_lock+0x10/0x10 [ 123.156571] nullb_group_make_group+0x20/0x100 [null_blk] [ 123.157011] configfs_mkdir+0x47b/0xc70 [ 123.157337] ? __pfx_configfs_mkdir+0x10/0x10 [ 123.157719] ? may_create_dentry+0x242/0x2e0 [ 123.158061] vfs_mkdir+0x2a9/0x6c0 [ 123.158352] filename_mkdirat+0x3dc/0x500 [ 123.158710] ? __pfx_filename_mkdirat+0x10/0x10 [ 123.159070] ? strncpy_from_user+0x3a/0x1d0 [ 123.159413] __x64_sys_mkdir+0x6b/0x90 [ 123.159760] do_syscall_64+0xea/0x600 Replace the runtime mutex_init(&lock) with a static DEFINE_MUTEX(lock) declaration to fix this issue.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b f9f4ca45c770b7eec83fea6c9b727b26e691b513 git Not specified
CNA Linux Linux affected 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b 349903f7ee72f7ac5b7a98840d701b2082d140a3 git Not specified
CNA Linux Linux affected 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b 0a8c2f7b95981913ac370683e34db4906970c210 git Not specified
CNA Linux Linux affected 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b c7dea90c9b4ef1dfbd2e4df36de180c76fd7c33c git Not specified
CNA Linux Linux affected 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b 234117949da3b3f9705a21b66094f9f30bbe681d git Not specified
CNA Linux Linux affected 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b 017dac7670909eaea3eb36e6b3b5a8be9ce0a14d git Not specified
CNA Linux Linux affected 5.19 Not specified
CNA Linux Linux unaffected 5.19 semver Not specified
CNA Linux Linux unaffected 6.1.188 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.157 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.52 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.6 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/f9f4ca45c770b7eec83fea6c9b727b26e691b513 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/234117949da3b3f9705a21b66094f9f30bbe681d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/017dac7670909eaea3eb36e6b3b5a8be9ce0a14d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0a8c2f7b95981913ac370683e34db4906970c210 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c7dea90c9b4ef1dfbd2e4df36de180c76fd7c33c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/349903f7ee72f7ac5b7a98840d701b2082d140a3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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