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Re: [Qemu-devel] [Qemu-arm] [PATCH for-2.9] hw/misc/imx6_src: Don't cras
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [Qemu-arm] [PATCH for-2.9] hw/misc/imx6_src: Don't crash trying to reset missing CPUs |
Date: |
Tue, 14 Mar 2017 12:53:21 +0100 |
Ping for review...
thanks
-- PMM
On 3 March 2017 at 12:59, Peter Maydell <address@hidden> wrote:
> Commit 4881658a4b introduced a call to arm_get_cpu_by_id(),
> and Coverity noticed that we weren't checking that it didn't
> return NULL (CID 1371652).
>
> Normally this won't happen (because all 4 CPUs are expected
> to exist), but it's possible the user requested fewer CPUs
> on the command line. Handle this possibility by silently
> doing nothing, which is the same behaviour as before commit
> 4881658a4b and also how we handle the other CPU operations
> (since we ignore the INVALID_PARAM returns from arm_set_cpu_on()
> and friends).
>
> There is a slight behavioural difference to the pre-4881658a4b
> situation: the "reset this core" bit will remain set rather
> than not being permitted to be set. The imx6 datasheet is
> unclear about the behaviour in this odd corner case, so we
> opt for the simpler code rather than complicated logic to
> maintain identical behaviour.
>
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> I couldn't actually get this to crash even with -smp 1 with
> my test image, but we should fix it anyhow.
>
> hw/misc/imx6_src.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/hw/misc/imx6_src.c b/hw/misc/imx6_src.c
> index edbb756..cfb0871 100644
> --- a/hw/misc/imx6_src.c
> +++ b/hw/misc/imx6_src.c
> @@ -143,13 +143,17 @@ static void imx6_defer_clear_reset_bit(int cpuid,
> unsigned long reset_shift)
> {
> struct SRCSCRResetInfo *ri;
> + CPUState *cpu = arm_get_cpu_by_id(cpuid);
> +
> + if (!cpu) {
> + return;
> + }
>
> ri = g_malloc(sizeof(struct SRCSCRResetInfo));
> ri->s = s;
> ri->reset_bit = reset_shift;
>
> - async_run_on_cpu(arm_get_cpu_by_id(cpuid), imx6_clear_reset_bit,
> - RUN_ON_CPU_HOST_PTR(ri));
> + async_run_on_cpu(cpu, imx6_clear_reset_bit, RUN_ON_CPU_HOST_PTR(ri));
> }
>
>
> --
> 2.7.4