In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
dmaengine: Fix device kref underflow in dma_chan_put()<\/p>\n
dma_chan_get() takes chan->device->ref only on the slow path:<\/p>\n
\t\/* no kref on fast path *\/
\n\tif (chan->client_count) {
\n\t\t__module_get(owner);
\n\t\tchan->client_count++;
\n\t\treturn 0;
\n\t}
\n\tif (!try_module_get(owner))
\n\t\treturn -ENODEV;
\n\tif (!dma_device_get(chan->device)) { \/\/ calls kref_get_unless_zero()<\/p>\n
dma_chan_put() drops the ref unconditionally, so every fast-path
\nget\/put pair drops one extra device reference.<\/p>\n
The bug fires when two conditions hold together: a non-private
\nprovider has a persistent client holding chan->client_count > 0
\nand another client cycles dmaengine_get()\/dmaengine_put().
\nWhen the kref hits zero, the subsequent dma_find_channel() returns
\nNULL even though the provider module is still loaded.<\/p>\n
Fix this by dropping device->ref only on the last put, matching the
\nsingle slow-path get.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
dmaengine: Fix device kref underflow in dma_chan_put()<\/p>\n
dma_chan_get() takes chan->device->ref only on the slow path:<\/p>\n
\t\/* no kref <\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-33413","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/33413","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=33413"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=33413"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=33413"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}