diff mbox series

[v3,32/34] s390/unwind: Disable KMSAN checks

Message ID 20231213233605.661251-33-iii@linux.ibm.com (mailing list archive)
State New
Headers show
Series kmsan: Enable on s390 | expand

Commit Message

Ilya Leoshkevich Dec. 13, 2023, 11:24 p.m. UTC 
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.

Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 arch/s390/kernel/unwind_bc.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Heiko Carstens Jan. 2, 2024, 3:09 p.m. UTC | #1 
On Thu, Dec 14, 2023 at 12:24:52AM +0100, Ilya Leoshkevich wrote:
> 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.
> 
> Reviewed-by: Alexander Potapenko <glider@google.com>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>  arch/s390/kernel/unwind_bc.c | 4 ++++
>  1 file changed, 4 insertions(+)

Acked-by: Heiko Carstens <hca@linux.ibm.com>
diff mbox series

Patch

diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c
index 0ece156fdd7c..cd44be2b6ce8 100644
--- a/arch/s390/kernel/unwind_bc.c
+++ b/arch/s390/kernel/unwind_bc.c
@@ -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)
 {