diff mbox series

[v2,26/33] s390/ftrace: Unpoison ftrace_regs in kprobe_ftrace_handler()

Message ID 20231121220155.1217090-27-iii@linux.ibm.com
State New
Headers
Series kmsan: Enable on s390 |

Commit Message

Ilya Leoshkevich Nov. 21, 2023, 10:01 p.m. UTC 
  s390 uses assembly code to initialize ftrace_regs and call
kprobe_ftrace_handler(). Therefore, from the KMSAN's point of view,
ftrace_regs is poisoned on kprobe_ftrace_handler() entry. This causes
KMSAN warnings when running the ftrace testsuite.

Fix by trusting the assembly code and always unpoisoning ftrace_regs in
kprobe_ftrace_handler().

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 arch/s390/kernel/ftrace.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Alexander Potapenko Dec. 8, 2023, 2:18 p.m. UTC | #1 
On Tue, Nov 21, 2023 at 11:02 PM Ilya Leoshkevich <iii@linux.ibm.com> wrote:
>
> s390 uses assembly code to initialize ftrace_regs and call
> kprobe_ftrace_handler(). Therefore, from the KMSAN's point of view,
> ftrace_regs is poisoned on kprobe_ftrace_handler() entry. This causes
> KMSAN warnings when running the ftrace testsuite.
>
> Fix by trusting the assembly code and always unpoisoning ftrace_regs in
> kprobe_ftrace_handler().
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
diff mbox series

Patch

diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index c46381ea04ec..3bad34eaa51e 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -300,6 +300,7 @@  void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 	if (bit < 0)
 		return;
 
+	kmsan_unpoison_memory(fregs, sizeof(*fregs));
 	regs = ftrace_get_regs(fregs);
 	p = get_kprobe((kprobe_opcode_t *)ip);
 	if (!regs || unlikely(!p) || kprobe_disabled(p))