{"schema_version":"1.9.0","id":"CVE-2025-68823","published":"2026-01-13T15:29:25.392Z","modified":"2026-08-12T03:51:35.756425851Z","summary":"ublk: fix deadlock when reading partition table","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix deadlock when reading partition table\n\nWhen one process(such as udev) opens ublk block device (e.g., to read\nthe partition table via bdev_open()), a deadlock[1] can occur:\n\n1. bdev_open() grabs disk->open_mutex\n2. The process issues read I/O to ublk backend to read partition table\n3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()\n   runs bio->bi_end_io() callbacks\n4. If this triggers fput() on file descriptor of ublk block device, the\n   work may be deferred to current task's task work (see fput() implementation)\n5. This eventually calls blkdev_release() from the same context\n6. blkdev_release() tries to grab disk->open_mutex again\n7. Deadlock: same task waiting for a mutex it already holds\n\nThe fix is to run blk_update_request() and blk_mq_end_request() with bottom\nhalves disabled. This forces blkdev_release() to run in kernel work-queue\ncontext instead of current task work context, and allows ublk server to make\nforward progress, and avoids the deadlock.\n\n[axboe: rewrite comment in ublk]","affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"71f28f3136aff5890cd56de78abc673f8393cad9"},{"fixed":"27bb79b7717b2fbb111a1c13548b2786ee712dca"},{"fixed":"64c0b7e2293757e8320f13434cd809f1c9257a62"},{"fixed":"9bcc47343ee0ef346aa7b2b460c8ff56bd882fe7"},{"fixed":"0460e09a614291f06c008443f47393c37b7358e7"},{"fixed":"c258f5c4502c9667bccf5d76fa731ab9c96687c1"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-68823.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.1.175"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.124"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.70"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-68823.json"}}],"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0460e09a614291f06c008443f47393c37b7358e7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/27bb79b7717b2fbb111a1c13548b2786ee712dca"},{"type":"WEB","url":"https://git.kernel.org/stable/c/64c0b7e2293757e8320f13434cd809f1c9257a62"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9bcc47343ee0ef346aa7b2b460c8ff56bd882fe7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c258f5c4502c9667bccf5d76fa731ab9c96687c1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68823.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-68823"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68823.json"}}