Re: [PATCH v2] plugins: fix qemu_plugin_reset

["Alex Bennée" <alex.bennee@linaro.org>]

Pierrick Bouvier <pierrick.bouvier@linaro.org> writes:

> 34e5e1 refactored the plugin context initialization. After this change,
> tcg_ctx->plugin_insn is not reset inconditionnally anymore, but only if
> one plugin at least is active.
>
> When uninstalling the last plugin active, we stopped reinitializing
> tcg_ctx->plugin_insn, which leads to memory callbacks being emitted.
> This results in an error as they don't appear in a plugin op sequence as
> expected.
>
> The correct fix is to make sure we reset plugin translation variables
> after current block translation ends. This way, we can catch any
> potential misuse of those after a given block, in more than fixing the
> current bug.
>
> v2: do not reset tcg_ctx->plugin_tb as it gets reused between
> translations.

For reference put version information bellow

---

and then the git tools will trim it out of the commit message.

Queued to plugins/next, thanks.

>
> Fixes: https://gitlab.com/qemu-project/qemu/-/issues/2570
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
> ---
>  accel/tcg/plugin-gen.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/accel/tcg/plugin-gen.c b/accel/tcg/plugin-gen.c
> index 2ee4c22befd..0f47bfbb489 100644
> --- a/accel/tcg/plugin-gen.c
> +++ b/accel/tcg/plugin-gen.c
> @@ -467,4 +467,8 @@ void plugin_gen_tb_end(CPUState *cpu, size_t num_insns)
>  
>      /* inject the instrumentation at the appropriate places */
>      plugin_gen_inject(ptb);
> +
> +    /* reset plugin translation state (plugin_tb is reused between blocks) */
> +    tcg_ctx->plugin_db = NULL;
> +    tcg_ctx->plugin_insn = NULL;
>  }

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro