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vfio/spapr_tce: Get rid of possible infinite loop

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As a part of cleanup, the SPAPR TCE IOMMU subdriver releases preregistered
memory. If there is a bug in memory release, the loop in
tce_iommu_release() becomes infinite; this actually happened to me.

This makes the loop finite and prints a warning on every failure to make
the code more bug prone.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Alexey Kardashevskiy 2018-10-02 13:22:31 +10:00 committed by Michael Ellerman
parent fa1ada7889
commit 517ad4ae8a
1 changed files with 3 additions and 7 deletions
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10
drivers/vfio/vfio_iommu_spapr_tce.c
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@ -371,6 +371,7 @@ static void tce_iommu_release(void *iommu_data)
{
struct tce_container *container = iommu_data;
struct tce_iommu_group *tcegrp;
struct tce_iommu_prereg *tcemem, *tmtmp;
long i;
while (tce_groups_attached(container)) {
@ -393,13 +394,8 @@ static void tce_iommu_release(void *iommu_data)
tce_iommu_free_table(container, tbl);
}
while (!list_empty(&container->prereg_list)) {
struct tce_iommu_prereg *tcemem;
tcemem = list_first_entry(&container->prereg_list,
struct tce_iommu_prereg, next);
WARN_ON_ONCE(tce_iommu_prereg_free(container, tcemem));
}
list_for_each_entry_safe(tcemem, tmtmp, &container->prereg_list, next)
WARN_ON(tce_iommu_prereg_free(container, tcemem));
tce_iommu_disable(container);
if (container->mm)