In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
sched_ext: Fix this_rq() assumptions in dispatch kfuncs<\/p>\n
Under core scheduling, dispatch runs from within the core-wide pick and can
\ntarget a sibling rq, so ops.dispatch() may execute on a CPU different from
\nthe dispatched rq’s. Several kfunc paths assumed the two always coincide:<\/p>\n
– scx_dsq_move() decided whether an rq lock is held by testing this_rq()’s
\n rq flags and lock-danced accordingly. A dispatch for a sibling took the
\n unlocked-context branch and acquired the source rq lock on top of the
\n already held dispatched rq lock which could deadlock.<\/p>\n
– scx_bpf_sub_dispatch() dispatched this_rq() with its stashed
\n sub_dispatch_prev, which is NULL when dispatching for a sibling.<\/p>\n
– finish_dispatch(), scx_bpf_dsq_reenq() and scx_bpf_dsq_nr_queued()
\n resolved SCX_DSQ_LOCAL to this CPU’s local DSQ rather than the dispatched
\n rq’s. The latter two are callable from other rq-locked operations too,
\n where SCX_DSQ_LOCAL now likewise resolves to the op’s rq. This changes
\n behavior also without core scheduling, e.g. for ops.enqueue() running a
\n remote wakeup on the waking CPU, and is intended: which CPU happens to
\n execute an operation is incidental, the op’s rq is what it is operating
\n on, and the resolution now matches the insert side where SCX_DSQ_LOCAL
\n dispatches land on the task’s rq.<\/p>\n
Use the rq tracked by scx_locked_rq(), which is set to the dispatched rq
\naround ops invocations and NULL in unlocked contexts.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
sched_ext: Fix this_rq() assumptions in dispatch kfuncs<\/p>\n
Under core scheduling, dispatch runs from within the core-wide pick and ca<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21440","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21440","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=21440"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21440"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21440"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}