In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
tracing: Free histogram var refs regardless of how often they are referenced<\/p>\n
Using the same variable three or more times in one hist trigger leaks the
\nvariable reference and its strings when the trigger is removed.<\/p>\n
commit 656fe2ba85e8 (“tracing: Use hist trigger’s var_ref array to destroy
\nvar_refs”) made a trigger’s var_refs[] array the only owner of a var ref:
\ndestroy_hist_field() returns early for HIST_FIELD_FL_VAR_REF, so the field
\nexpressions never destroy one. One entry, freed once, no count needed.<\/p>\n
commit 8bcebc77e85f (“tracing: Fix histogram code when expression has same
\nvar as value”) then made repeated references share one object and added a
\ncount of them. Only the increment side exists, since those expressions
\nstill return early and never drop a reference, so __destroy_hist_field()
\nsees how many references were created rather than how many are left. It
\nfrees when the decremented count is 0 or 1, so two references work and
\nthree or more leak.<\/p>\n
Sharing kept one array entry per object, and create_var_ref() searches and
\nappends within a single trigger, so nothing outside it holds the object.
\nRemoving a trigger whose variables are still referenced is already refused
\nby check_var_refs() with -EBUSY. Drop the count and free unconditionally.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
tracing: Free histogram var refs regardless of how often they are referenced<\/p>\n
Using the same variable three or more times in one hi<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-29078","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/29078","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=29078"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=29078"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=29078"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}