Unlike patch_text(), patch_text_nosync() takes the length in bytes, not number of instructions. It is therefore wrong for arch_prepare_ss_slot() to pass length=1 while patching one instruction.

This bug was introduced by commit b1756750a397 ("riscv: kprobes: Use patch_text_nosync() for insn slots"). It has been fixed upstream by commit 51781ce8f448 ("riscv: Pass patch_text() the length in bytes"). However, beside fixing this bug, this commit does many other things, making it unsuitable for backporting.

Fix it by properly passing the lengths in bytes.

Fixes: b1756750a397 ("riscv: kprobes: Use patch_text_nosync() for insn slots") Signed-off-by: Nam Cao namcao@linutronix.de --- arch/riscv/kernel/probes/kprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c index 4fbc70e823f0..dc431b965bc3 100644 --- a/arch/riscv/kernel/probes/kprobes.c +++ b/arch/riscv/kernel/probes/kprobes.c @@ -28,8 +28,8 @@ static void __kprobes arch_prepare_ss_slot(struct kprobe *p)

p->ainsn.api.restore = (unsigned long)p->addr + offset;

- patch_text_nosync(p->ainsn.api.insn, &p->opcode, 1); - patch_text_nosync((void *)p->ainsn.api.insn + offset, &insn, 1); + patch_text_nosync(p->ainsn.api.insn, &p->opcode, offset); + patch_text_nosync((void *)p->ainsn.api.insn + offset, &insn, sizeof(insn)); }

static void __kprobes arch_prepare_simulate(struct kprobe *p)