"value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntmpfs: fix race on handling dquot rbtree\n\nA syzkaller reproducer found a race while attempting to remove dquot\ninformation from the rb tree.\n\nFetching the rb_tree root node must also be protected by the\ndqopt->dqio_sem, otherwise, giving the right timing, shmem_release_dquot()\nwill trigger a warning because it couldn't find a node in the tree, when\nthe real reason was the root node changing before the search starts:\n\nThread 1\t\t\t\tThread 2\n- shmem_release_dquot()\t\t\t- shmem_{acquire,release}_dquot()\n\n- fetch ROOT\t\t\t\t- Fetch ROOT\n\n\t\t\t\t\t- acquire dqio_sem\n- wait dqio_sem\n\n\t\t\t\t\t- do something, triger a tree rebalance\n\t\t\t\t\t- release dqio_sem\n\n- acquire dqio_sem\n- start searching for the node, but\n from the wrong location, missing\n the node, and triggering a warning."
