ghsa-3574-q5g6-f77j
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
lib/group_cpus: fix NULL pointer dereference from group_cpus_evenly()
While testing null_blk with configfs, echo 0 > poll_queues will trigger following panic:
BUG: kernel NULL pointer dereference, address: 0000000000000010 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 27 UID: 0 PID: 920 Comm: bash Not tainted 6.15.0-02023-gadbdb95c8696-dirty #1238 PREEMPT(undef) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:__bitmap_or+0x48/0x70 Call Trace: __group_cpus_evenly+0x822/0x8c0 group_cpus_evenly+0x2d9/0x490 blk_mq_map_queues+0x1e/0x110 null_map_queues+0xc9/0x170 [null_blk] blk_mq_update_queue_map+0xdb/0x160 blk_mq_update_nr_hw_queues+0x22b/0x560 nullb_update_nr_hw_queues+0x71/0xf0 [null_blk] nullb_device_poll_queues_store+0xa4/0x130 [null_blk] configfs_write_iter+0x109/0x1d0 vfs_write+0x26e/0x6f0 ksys_write+0x79/0x180 __x64_sys_write+0x1d/0x30 x64_sys_call+0x45c4/0x45f0 do_syscall_64+0xa5/0x240 entry_SYSCALL_64_after_hwframe+0x76/0x7e
Root cause is that numgrps is set to 0, and ZERO_SIZE_PTR is returned from kcalloc(), and later ZERO_SIZE_PTR will be deferenced.
Fix the problem by checking numgrps first in group_cpus_evenly(), and return NULL directly if numgrps is zero.
[yukuai3@huawei.com: also fix the non-SMP version]
{
"affected": [],
"aliases": [
"CVE-2025-38255"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-09T11:15:27Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nlib/group_cpus: fix NULL pointer dereference from group_cpus_evenly()\n\nWhile testing null_blk with configfs, echo 0 \u003e poll_queues will trigger\nfollowing panic:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000010\nOops: Oops: 0000 [#1] SMP NOPTI\nCPU: 27 UID: 0 PID: 920 Comm: bash Not tainted 6.15.0-02023-gadbdb95c8696-dirty #1238 PREEMPT(undef)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014\nRIP: 0010:__bitmap_or+0x48/0x70\nCall Trace:\n \u003cTASK\u003e\n __group_cpus_evenly+0x822/0x8c0\n group_cpus_evenly+0x2d9/0x490\n blk_mq_map_queues+0x1e/0x110\n null_map_queues+0xc9/0x170 [null_blk]\n blk_mq_update_queue_map+0xdb/0x160\n blk_mq_update_nr_hw_queues+0x22b/0x560\n nullb_update_nr_hw_queues+0x71/0xf0 [null_blk]\n nullb_device_poll_queues_store+0xa4/0x130 [null_blk]\n configfs_write_iter+0x109/0x1d0\n vfs_write+0x26e/0x6f0\n ksys_write+0x79/0x180\n __x64_sys_write+0x1d/0x30\n x64_sys_call+0x45c4/0x45f0\n do_syscall_64+0xa5/0x240\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nRoot cause is that numgrps is set to 0, and ZERO_SIZE_PTR is returned from\nkcalloc(), and later ZERO_SIZE_PTR will be deferenced.\n\nFix the problem by checking numgrps first in group_cpus_evenly(), and\nreturn NULL directly if numgrps is zero.\n\n[yukuai3@huawei.com: also fix the non-SMP version]",
"id": "GHSA-3574-q5g6-f77j",
"modified": "2025-07-09T12:31:35Z",
"published": "2025-07-09T12:31:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38255"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/29d39e0d5f16c060e32542b2cf351c09fd22b250"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/64a99eff8dcf1f951a544e6058341b2b19a8fdbd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/911ef2e8a7de5b2bae8ff11fb0bd01f699e6db65"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/df831e97739405ecbaddb85516bc7d4d1c933d6b"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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