APPLIED[J]: [SRU][B/J/K/OEM-5.14/OEM-5.17/OEM-6.0][PATCH v2 1/1] x86/bugs: Flush IBP in ib_prctl_set()

[Stefan Bader]

On 09.02.23 21:10, Yuxuan Luo wrote:
> From: Rodrigo Branco <bsdaemon at google.com>
> 
> We missed the window between the TIF flag update and the next reschedule.
> 
> Signed-off-by: Rodrigo Branco <bsdaemon at google.com>
> Reviewed-by: Borislav Petkov (AMD) <bp at alien8.de>
> Signed-off-by: Ingo Molnar <mingo at kernel.org>
> Cc: <stable at vger.kernel.org>
> (cherry picked from commit a664ec9158eeddd75121d39c9a0758016097fa96)
> CVE-2023-0045
> Signed-off-by: Yuxuan Luo <yuxuan.luo at canonical.com>
> ---
>   arch/x86/kernel/cpu/bugs.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
> index fc4bee4b17fb7..45f21906e7ab6 100644
> --- a/arch/x86/kernel/cpu/bugs.c
> +++ b/arch/x86/kernel/cpu/bugs.c
> @@ -1776,6 +1776,8 @@ static int ib_prctl_set(struct task_struct *task, unsigned long ctrl)
>   		if (ctrl == PR_SPEC_FORCE_DISABLE)
>   			task_set_spec_ib_force_disable(task);
>   		task_update_spec_tif(task);
> +		if (task == current)
> +			indirect_branch_prediction_barrier();
>   		break;
>   	default:
>   		return -ERANGE;

Applied to jammy:linux/master-next. Thanks.

-Stefan
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