On Wed, Dec 23, 2020 at 02:24:12PM +0800, Zhenzhong Duan wrote:
> check_iommu_entries() checks for cyclic dependency in iommu entries
> and fixes the cyclic dependency by setting x->depend to NULL. But
> this repairing isn't correct if q is in front of p, there will be
> "EXECUTION ORDER INVALID!" report following. Fix it by NULLing
> whichever in the front.
>
> The second issue is about the report of exectuion order reverse,
> the order is reversed incorrectly in the report, fix it.
Heya!
When you debugged this, did you by any chance save the
serial logs and the debug logs to double-check it?
Thanks!
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@gmail.com>
> ---
> arch/x86/kernel/pci-iommu_table.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/pci-iommu_table.c
> b/arch/x86/kernel/pci-iommu_table.c
> index 2e9006c..40c8249 100644
> --- a/arch/x86/kernel/pci-iommu_table.c
> +++ b/arch/x86/kernel/pci-iommu_table.c
> @@ -60,7 +60,10 @@ void __init check_iommu_entries(struct iommu_table_entry
> *start,
> printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %pS depends
> on %pS and vice-versa. BREAKING IT.\n",
> p->detect, q->detect);
> /* Heavy handed way..*/
> - x->depend = NULL;
> + if (p > q)
> + q->depend = NULL;
> + else
> + p->depend = NULL;
> }
> }
>
> @@ -68,7 +71,7 @@ void __init check_iommu_entries(struct iommu_table_entry
> *start,
> q = find_dependents_of(p, finish, p);
> if (q && q > p) {
> printk(KERN_ERR "EXECUTION ORDER INVALID! %pS should be
> called before %pS!\n",
> - p->detect, q->detect);
> + q->detect, p->detect);
> }
> }
> }
> --
> 1.8.3.1
>
