13ed255248
[ Upstream commit 534103bcd52ca9c1fecbc70e717b4a538dc4ded8 ]
When unbinding pasid - a race condition exists vs outstanding page faults.
To prevent this, the pasid_state object contains a refcount.
* set to 1 on pasid bind
* incremented on each ppr notification start
* decremented on each ppr notification done
* decremented on pasid unbind
Since refcount_dec assumes that refcount will never reach 0:
the current implementation causes the following to be invoked on
pasid unbind:
REFCOUNT_WARN("decrement hit 0; leaking memory")
Fix this issue by changing refcount_dec to refcount_dec_and_test
to explicitly handle refcount=1.
Fixes:
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|---|---|---|
| .. | ||
| amd_iommu_types.h | ||
| amd_iommu.h | ||
| debugfs.c | ||
| init.c | ||
| io_pgtable_v2.c | ||
| io_pgtable.c | ||
| iommu_v2.c | ||
| iommu.c | ||
| Kconfig | ||
| Makefile | ||
| quirks.c | ||