In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
perf\/core: Fix a refcount leak in attach_perf_ctx_data()<\/p>\n
The attach_perf_ctx_data() can race on global and !global cases. The
\nglobal case is protected by global_ctx_data_rwsem and shares a single
\nreference count using perf_ctx_data.global field.<\/p>\n
But when it races with !global case, it may miss to set the global field
\nand result in a reference count leak.<\/p>\n
CPU1 CPU2
\n —————————————————————-
\n attach_task_ctx_data(.global=1) attach_task_ctx_data(.global=0)
\n cd1 = alloc_perf_ctx_data(); cd2 = alloc_perf_ctx_data();
\n \/\/ { .global = 0, .refcount = 1 };<\/p>\n
try_cmpxchg(); \/\/ success,
\n \/\/ task->perf_ctx_data = cd2
\n try_cmpxhg(); \/\/ fail; old = cd2
\n refcount_inc_not_zero(&old->refcount); \/\/ success
\n \/\/ old.refcount = 2
\n free_perf_ctx_data(cd1);<\/p>\n
Then later detach_global_ctx_data() will see the data but it’s not
\nmarked as global, so it won’t call detach_task_ctx_data().<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
perf\/core: Fix a refcount leak in attach_perf_ctx_data()<\/p>\n
The attach_perf_ctx_data() can race on global and !global cases. The
\nglo<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-41024","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/41024","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=41024"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41024"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41024"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}