{"id":"CVE-2023-53823","revision":"5bc4b12363c14679bbc605b4f0ad63e5","records":[{"revision":"5bc4b12363c14679bbc605b4f0ad63e5","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2023-53823","aliases":[],"title":"block/rq_qos: protect rq_qos apis with a new lock","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock/rq_qos: protect rq_qos apis with a new lock\n\ncommit 50e34d78815e (\"block: disable the elevator int del_gendisk\")\nmove rq_qos_exit() from disk_release() to del_gendisk(), this will\nintroduce some problems:\n\n1) If rq_qos_add() is triggered by enabling iocost/iolatency through\n   cgroupfs, then it can concurrent with del_gendisk(), it's not safe to\n   write 'q->rq_qos' concurrently.\n\n2) Activate cgroup policy that is relied on rq_qos will call\n   rq_qos_add() and blkcg_activate_policy(), and if rq_qos_exit() is\n   called in the middle, null-ptr-dereference will be triggered in\n   blkcg_activate_policy().\n\n3) blkg_conf_open_bdev() can call blkdev_get_no_open() first to find the\n   disk, then if rq_qos_exit() from del_gendisk() is done before\n   rq_qos_add(), then memory will be leaked.\n\nThis patch add a new disk level mutex 'rq_qos_mutex':\n\n1) The lock will protect rq_qos_exit() directly.\n\n2) For wbt that doesn't relied on blk-cgroup, rq_qos_add() can only be\n   called from disk initialization for now because wbt can't be\n   destructed until rq_qos_exit(), so it's safe not to protect wbt for\n   now. Hoever, in case that rq_qos dynamically destruction is supported\n   in the furture, this patch also protect rq_qos_add() from wbt_init()\n   directly, this is enough because blk-sysfs already synchronize\n   writers with disk removal.\n\n3) For iocost and iolatency, in order to synchronize disk removal and\n   cgroup configuration, the lock is held after blkdev_get_no_open()\n   from blkg_conf_open_bdev(), and is released in blkg_conf_exit().\n   In order to fix the above memory leak, disk_live() is checked after\n   holding the new lock.","state":0,"publishedAt":"2025-12-09T01:29:36.343+00:00","modifiedAt":"2026-08-05T09:16:14.72+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"block/blk-cgroup.c\",\n                        \"block/blk-core.c\",\n                        \"block/blk-rq-qos.c\",\n                        \"block/blk-wbt.c\",\n                        \"include/linux/blkdev.h\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"50e34d78815e474d410f342fbe783b18192ca518\",\n                            \"lessThan\": \"16398b4638b5cd8c1dc95fc940a1591a801d53ce\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"50e34d78815e474d410f342fbe783b18192ca518\",\n                            \"lessThan\": \"a13bd91be22318768d55470cbc0b0f4488ef9edf\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f28699fafc047ec33299da01e928c3a0073c5cc6\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5.18.8\",\n                            \"lessThan\": \"5.19\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"block/blk-cgroup.c\",\n                        \"block/blk-core.c\",\n                        \"block/blk-rq-qos.c\",\n                        \"block/blk-wbt.c\",\n                        \"include/linux/blkdev.h\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.19\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.19\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.4.4\",\n                            \"lessThanOrEqual\": \"6.4.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.5\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/16398b4638b5cd8c1dc95fc940a1591a801d53ce","https://git.kernel.org/stable/c/a13bd91be22318768d55470cbc0b0f4488ef9edf"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-53823","license":"CVE Program Terms of Use","key":"cve-program:CVE-2023-53823","identifiers":["CVE-2023-53823"]},"retained":false,"historicalAffected":[]}],"coverage":[]}