GHSA-HJGX-24CQ-764X
Vulnerability from github – Published: 2026-02-14 18:30 – Updated: 2026-03-19 18:31In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock or per-VMA lock, whichever was used to lock VMA under question, to avoid deadlock reported by syzbot:
-> #1 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xed/0x170 _copy_to_iter+0x118/0x1720 copy_page_to_iter+0x12d/0x1e0 filemap_read+0x720/0x10a0 blkdev_read_iter+0x2b5/0x4e0 vfs_read+0x7f4/0xae0 ksys_read+0x12a/0x250 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}: __lock_acquire+0x1509/0x26d0 lock_acquire+0x185/0x340 down_read+0x98/0x490 blkdev_read_iter+0x2a7/0x4e0 __kernel_read+0x39a/0xa90 freader_fetch+0x1d5/0xa80 __build_id_parse.isra.0+0xea/0x6a0 do_procmap_query+0xd75/0x1050 procfs_procmap_ioctl+0x7a/0xb0 __x64_sys_ioctl+0x18e/0x210 do_syscall_64+0xcb/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&mm->mmap_lock); lock(&sb->s_type->i_mutex_key#8); lock(&mm->mmap_lock); rlock(&sb->s_type->i_mutex_key#8);
*** DEADLOCK ***
This seems to be exacerbated (as we haven't seen these syzbot reports before that) by the recent:
777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context")
To make this safe, we need to grab file refcount while VMA is still locked, but other than that everything is pretty straightforward. Internal build_id_parse() API assumes VMA is passed, but it only needs the underlying file reference, so just add another variant build_id_parse_file() that expects file passed directly.
[akpm@linux-foundation.org: fix up kerneldoc]
{
"affected": [],
"aliases": [
"CVE-2026-23199"
],
"database_specific": {
"cwe_ids": [
"CWE-667"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-02-14T17:15:57Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nprocfs: avoid fetching build ID while holding VMA lock\n\nFix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock\nor per-VMA lock, whichever was used to lock VMA under question, to avoid\ndeadlock reported by syzbot:\n\n -\u003e #1 (\u0026mm-\u003emmap_lock){++++}-{4:4}:\n __might_fault+0xed/0x170\n _copy_to_iter+0x118/0x1720\n copy_page_to_iter+0x12d/0x1e0\n filemap_read+0x720/0x10a0\n blkdev_read_iter+0x2b5/0x4e0\n vfs_read+0x7f4/0xae0\n ksys_read+0x12a/0x250\n do_syscall_64+0xcb/0xf80\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n -\u003e #0 (\u0026sb-\u003es_type-\u003ei_mutex_key#8){++++}-{4:4}:\n __lock_acquire+0x1509/0x26d0\n lock_acquire+0x185/0x340\n down_read+0x98/0x490\n blkdev_read_iter+0x2a7/0x4e0\n __kernel_read+0x39a/0xa90\n freader_fetch+0x1d5/0xa80\n __build_id_parse.isra.0+0xea/0x6a0\n do_procmap_query+0xd75/0x1050\n procfs_procmap_ioctl+0x7a/0xb0\n __x64_sys_ioctl+0x18e/0x210\n do_syscall_64+0xcb/0xf80\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n other info that might help us debug this:\n\n Possible unsafe locking scenario:\n\n CPU0 CPU1\n ---- ----\n rlock(\u0026mm-\u003emmap_lock);\n lock(\u0026sb-\u003es_type-\u003ei_mutex_key#8);\n lock(\u0026mm-\u003emmap_lock);\n rlock(\u0026sb-\u003es_type-\u003ei_mutex_key#8);\n\n *** DEADLOCK ***\n\nThis seems to be exacerbated (as we haven\u0027t seen these syzbot reports\nbefore that) by the recent:\n\n\t777a8560fd29 (\"lib/buildid: use __kernel_read() for sleepable context\")\n\nTo make this safe, we need to grab file refcount while VMA is still locked, but\nother than that everything is pretty straightforward. Internal build_id_parse()\nAPI assumes VMA is passed, but it only needs the underlying file reference, so\njust add another variant build_id_parse_file() that expects file passed\ndirectly.\n\n[akpm@linux-foundation.org: fix up kerneldoc]",
"id": "GHSA-hjgx-24cq-764x",
"modified": "2026-03-19T18:31:14Z",
"published": "2026-02-14T18:30:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23199"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b5cbacd7f86f4f62b8813688c8e73be94e8e1951"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b9b97e6aeb534315f9646b2090d1a5024c6a4e82"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cbc03ce3e6ce7e21214c3f02218213574c1a2d08"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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