On Tue, 25 Aug 2026 20:02:10 +0000 Ricardo Ribalda <[email protected]> wrote:
> Recent versions of smatch preserved the address space qualifiers with > typeof()[1]. > > This fix has discovered an invalid casting in rcu dereference logic. > > This patch fixes tens of smatch errors like the following: > ./include/trace/events/vb2.h:46:1: warning: incorrect type in assignment > (different address spaces) > ./include/trace/events/vb2.h:46:1: expected struct tracepoint_func > *it_func_ptr > ./include/trace/events/vb2.h:46:1: got struct tracepoint_func __rcu * > > [1] > https://github.com/error27/smatch/commit/e53027a4e816a772403baafa83c09e4a94c1cb8f > > Signed-off-by: Ricardo Ribalda <[email protected]> > --- > include/linux/rcupdate.h | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > index 44c07a66edff..80276cedda80 100644 > --- a/include/linux/rcupdate.h > +++ b/include/linux/rcupdate.h > @@ -488,7 +488,7 @@ static __always_inline bool > lockdep_assert_rcu_helper(bool c, const struct __ctx > context_unsafe( > \ > typeof(*p) *local = (typeof(*p) *__force)(p); \ > rcu_check_sparse(p, __rcu); \ > - ((typeof(*p) __force __kernel *)(local)) \ > + ((TYPEOF_UNQUAL(*p) __force __kernel *)(local)) \ Ugg... TYPEOF_UNQUAL() is absolutely horrid... When __CHECKER__ is undefined the whole thing is just (p). I suspect reducing all the definitions would measurably improve kernel compile time (even before these changes). David > ) > /** > * unrcu_pointer - mark a pointer as not being RCU protected > @@ -503,7 +503,7 @@ context_unsafe( > \ > ({ \ > typeof(*p) *local = (typeof(*p) *__force)READ_ONCE(p); \ > rcu_check_sparse(p, space); \ > - ((typeof(*p) __force __kernel *)(local)); \ > + ((TYPEOF_UNQUAL(*p) __force __kernel *)(local)); \ > }) ) > #define __rcu_dereference_check(p, local, c, space) \ > ({ \ > @@ -511,19 +511,19 @@ context_unsafe( > \ > typeof(*p) *local = (typeof(*p) *__force)READ_ONCE(p); \ > RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_check() usage"); \ > rcu_check_sparse(p, space); \ > - ((typeof(*p) __force __kernel *)(local)); \ > + ((TYPEOF_UNQUAL(*p) __force __kernel *)(local)); \ > }) > #define __rcu_dereference_protected(p, local, c, space) \ > ({ \ > RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_protected() usage"); > \ > rcu_check_sparse(p, space); \ > - ((typeof(*p) __force __kernel *)(p)); \ > + ((TYPEOF_UNQUAL(*p) __force __kernel *)(p)); \ > }) > #define __rcu_dereference_raw(p, local) \ > ({ \ > /* Dependency order vs. p above. */ \ > typeof(p) local = READ_ONCE(p); \ > - ((typeof(*p) __force __kernel *)(local)); \ > + ((TYPEOF_UNQUAL(*p) __force __kernel *)(local)); \ > }) > #define rcu_dereference_raw(p) __rcu_dereference_raw(p, __UNIQUE_ID(rcu)) > >
