In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
blk-cgroup: fix race between policy activation and blkg destruction<\/p>\n
When switching an IO scheduler on a block device, blkcg_activate_policy()
\nallocates blkg_policy_data (pd) for all blkgs attached to the queue.
\nHowever, blkcg_activate_policy() may race with concurrent blkcg deletion,
\nleading to use-after-free and memory leak issues.<\/p>\n
The use-after-free occurs in the following race:<\/p>\n
T1 (blkcg_activate_policy):
\n – Successfully allocates pd for blkg1 (loop0->queue, blkcgA)
\n – Fails to allocate pd for blkg2 (loop0->queue, blkcgB)
\n – Enters the enomem rollback path to release blkg1 resources<\/p>\n
T2 (blkcg deletion):
\n – blkcgA is deleted concurrently
\n – blkg1 is freed via blkg_free_workfn()
\n – blkg1->pd is freed<\/p>\n
T1 (continued):
\n – Rollback path accesses blkg1->pd->online after pd is freed
\n – Triggers use-after-free<\/p>\n
In addition, blkg_free_workfn() frees pd before removing the blkg from
\nq->blkg_list. This allows blkcg_activate_policy() to allocate a new pd
\nfor a blkg that is being destroyed, leaving the newly allocated pd
\nunreachable when the blkg is finally freed.<\/p>\n
Fix these races by extending blkcg_mutex coverage to serialize
\nblkcg_activate_policy() rollback and blkg destruction, ensuring pd
\nlifecycle is synchronized with blkg list visibility.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
blk-cgroup: fix race between policy activation and blkg destruction<\/p>\n
When switching an IO scheduler on a block device, blkcg_activa<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-25735","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/25735","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=25735"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25735"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25735"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}