Commit 7e17eac2 authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Andrew Morton
Browse files

s390/unwind: disable KMSAN checks 

The unwind code can read uninitialized frames.  Furthermore, even in the
good case, KMSAN does not emit shadow for backchains.  Therefore disable
it for the unwinding functions.

Link: https://lkml.kernel.org/r/20240621113706.315500-37-iii@linux.ibm.com


Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Acked-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <kasan-dev@googlegroups.com>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e0bebfd6

arch/s390/kernel/unwind_bc.c

+4 −0
Original line number Diff line number Diff line
@@ -49,6 +49,8 @@ static inline bool is_final_pt_regs(struct unwind_state *state, 
	       READ_ONCE_NOCHECK(regs->psw.mask) & PSW_MASK_PSTATE;

}



/* Avoid KMSAN false positives from touching uninitialized frames. */

__no_kmsan_checks

bool unwind_next_frame(struct unwind_state *state)

{

	struct stack_info *info = &state->stack_info;
@@ -118,6 +120,8 @@ bool unwind_next_frame(struct unwind_state *state) 
}

EXPORT_SYMBOL_GPL(unwind_next_frame);



/* Avoid KMSAN false positives from touching uninitialized frames. */

__no_kmsan_checks

void __unwind_start(struct unwind_state *state, struct task_struct *task,

		    struct pt_regs *regs, unsigned long first_frame)

{