Re: [PATCH] accel/tcg: test CPUJumpCache in tb_jmp_cache_clear_page()

[Philippe Mathieu-Daudé]

On 3/2/23 18:15, Eric Auger wrote:
> After commit 4e4fa6c12d ("accel/tcg: Complete cpu initialization
> before registration"), it looks the CPUJumpCache handle can be NULL.
> This causes a SIGSEV when running debug-wp-migration kvm unit test.

Do you mean commit a976a99a29 ("include/hw/core: Create struct
CPUJumpCache") instead?

> At the first place it should be clarified why this TCG code is called
> with KVM acceleration. This may hide another bug.
>
> Fixes: 4e4fa6c12d ("accel/tcg: Complete cpu initialization before registration")
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> ---
>   accel/tcg/cputlb.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
> index 4e040a1cb9..ac0245ee6c 100644
> --- a/accel/tcg/cputlb.c
> +++ b/accel/tcg/cputlb.c
> @@ -103,6 +103,10 @@ static void tb_jmp_cache_clear_page(CPUState *cpu, 
> target_ulong page_addr)
>       int i, i0 = tb_jmp_cache_hash_page(page_addr);
>       CPUJumpCache *jc = cpu->tb_jmp_cache;
>   
> +    if (!jc) {

unlikely()?

> +        return;
> +    }
> +
>       for (i = 0; i < TB_JMP_PAGE_SIZE; i++) {
>           qatomic_set(&jc->array[i0 + i].tb, NULL);
>       }