In the Linux kernel, the following vulnerability has been resolved: kernel/fork: clear PF_BLOCK_TS in copy_process() PF_BLOCK_TS is only set in blk_time_get_ns() when current->plug is non-NULL, and blk_finish_plug() clears it via __blk_flush_plug() before NULLing the plug pointer. copy_process() breaks the invariant by inheriting PF_BLOCK_TS from the parent while resetting the child's plug to NULL. Clear PF_BLOCK_TS alongside that assignment so callers can rely on "PF_BLOCK_TS set implies current->plug != NULL" and dereference current->plug unguarded.
https://git.kernel.org/stable/c/fd38b75c4b43295b10d69772a46d1c74dbd6fc81
https://git.kernel.org/stable/c/ee0801aceabdf583392477baf69a290b09448b8f
https://git.kernel.org/stable/c/99e6c712cc300883b8cbf03347d5359ec1a4d6dd
https://git.kernel.org/stable/c/77bba61a20f1b3d206f4f90e10a7bb3cd90b9619