{"id":"CVE-2026-22980","summary":"nfsd: provide locking for v4_end_grace","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: provide locking for v4_end_grace\n\nWriting to v4_end_grace can race with server shutdown and result in\nmemory being accessed after it was freed - reclaim_str_hashtbl in\nparticularly.\n\nWe cannot hold nfsd_mutex across the nfsd4_end_grace() call as that is\nheld while client_tracking_op-\u003einit() is called and that can wait for\nan upcall to nfsdcltrack which can write to v4_end_grace, resulting in a\ndeadlock.\n\nnfsd4_end_grace() is also called by the landromat work queue and this\ndoesn't require locking as server shutdown will stop the work and wait\nfor it before freeing anything that nfsd4_end_grace() might access.\n\nHowever, we must be sure that writing to v4_end_grace doesn't restart\nthe work item after shutdown has already waited for it.  For this we\nadd a new flag protected with nn-\u003eclient_lock.  It is set only while it\nis safe to make client tracking calls, and v4_end_grace only schedules\nwork while the flag is set with the spinlock held.\n\nSo this patch adds a nfsd_net field \"client_tracking_active\" which is\nset as described.  Another field \"grace_end_forced\", is set when\nv4_end_grace is written.  After this is set, and providing\nclient_tracking_active is set, the laundromat is scheduled.\nThis \"grace_end_forced\" field bypasses other checks for whether the\ngrace period has finished.\n\nThis resolves a race which can result in use-after-free.","modified":"2026-04-02T17:30:19.300649Z","published":"2026-01-23T15:24:02.924Z","related":["SUSE-SU-2026:20838-1","SUSE-SU-2026:20931-1","openSUSE-SU-2026:20416-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/22xxx/CVE-2026-22980.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/22xxx/CVE-2026-22980.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-22980"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"7f5ef2e900d9462bf9cffaf6bb246ed87a20a6d6"},{"fixed":"ca97360860eb02e3ae4ba42c19b439a0fcecbf06"},{"fixed":"e8bfa2401d4c51eca6e48e9b33c798828ca9df61"},{"fixed":"34eb22836e0cdba093baac66599d68c4cd245a9d"},{"fixed":"06600719d0f7a723811c45e4d51f5b742f345309"},{"fixed":"ba4811c8b433bfa681729ca42cc62b6034f223b0"},{"fixed":"53f07d095e7e680c5e4569a55a019f2c0348cdc6"},{"fixed":"2857bd59feb63fcf40fe4baf55401baea6b4feb4"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-22980.json"}}],"schema_version":"1.7.5"}