{"id":14881,"date":"2026-09-04T19:02:16","date_gmt":"2026-09-04T11:02:16","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-63804"},"modified":"2026-09-04T19:02:16","modified_gmt":"2026-09-04T11:02:16","slug":"cve-2026-63804","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-63804","title":{"rendered":"CVE-2026-63804 [HIGH] &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\ngfs2: fix use-after-f"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>gfs2: fix use-after-free in gfs2_qd_dealloc<\/p>\n<p>gfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(),<br \/>\naccesses the superblock object sdp through qd-&gt;qd_sbd after freeing qd.<br \/>\nIt does so to decrement sd_quota_count and wake up sd_kill_wait.<\/p>\n<p>However, by the time the RCU callback runs, gfs2_put_super() may have<br \/>\nalready freed sdp via free_sbd().  This can happen when<br \/>\ngfs2_quota_cleanup() is called during unmount: it disposes of quota<br \/>\nobjects via call_rcu() and then waits on sd_kill_wait with a 60-second<br \/>\ntimeout.  If the timeout expires, or if gfs2_gl_hash_clear() triggers<br \/>\nadditional qd_put() calls that schedule more RCU callbacks after the<br \/>\nwait completes, gfs2_put_super() will proceed to free the superblock<br \/>\nwhile RCU callbacks referencing it are still pending.<\/p>\n<p>Add an rcu_barrier() before free_sbd() in gfs2_put_super() to ensure<br \/>\nall pending RCU callbacks (including gfs2_qd_dealloc) have completed<br \/>\nbefore the superblock is freed.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>gfs2: fix use-after-free in gfs2_qd_dealloc<\/p>\n<p>gfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(),<br \/>\naccesses the supe<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-14881","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/14881","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=14881"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14881"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14881"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}