From d4e3b928ab487a8aecd1f6a140b40ac365116cfb Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Fri, 17 Nov 2023 19:13:27 -0500 Subject: closures: CLOSURE_CALLBACK() to fix type punning Control flow integrity is now checking that type signatures match on indirect function calls. That breaks closures, which embed a work_struct in a closure in such a way that a closure_fn may also be used as a workqueue fn by the underlying closure code. So we have to change closure fns to take a work_struct as their argument - but that results in a loss of clarity, as closure fns have different semantics from normal workqueue functions (they run owning a ref on the closure, which must be released with continue_at() or closure_return()). Thus, this patc introduces CLOSURE_CALLBACK() and closure_type() macros as suggested by Kees, to smooth things over a bit. Suggested-by: Kees Cook Cc: Coly Li Signed-off-by: Kent Overstreet --- lib/closure.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'lib/closure.c') diff --git a/lib/closure.c b/lib/closure.c index f86c9eeafb35..c16540552d61 100644 --- a/lib/closure.c +++ b/lib/closure.c @@ -36,7 +36,7 @@ static inline void closure_put_after_sub(struct closure *cl, int flags) closure_debug_destroy(cl); if (destructor) - destructor(cl); + destructor(&cl->work); if (parent) closure_put(parent); @@ -108,8 +108,9 @@ struct closure_syncer { int done; }; -static void closure_sync_fn(struct closure *cl) +static CLOSURE_CALLBACK(closure_sync_fn) { + struct closure *cl = container_of(ws, struct closure, work); struct closure_syncer *s = cl->s; struct task_struct *p; -- cgit