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H A D | init_64.c | 18f38132 Mon Aug 04 18:34:01 CDT 2014 David S. Miller <davem@davemloft.net> sparc64: Do not insert non-valid PTEs into the TSB hash table.
The assumption was that update_mmu_cache() (and the equivalent for PMDs) would only be called when the PTE being installed will be accessible by the user.
This is not true for code paths originating from remove_migration_pte().
There are dire consequences for placing a non-valid PTE into the TSB. The TLB miss frramework assumes thatwhen a TSB entry matches we can just load it into the TLB and return from the TLB miss trap.
So if a non-valid PTE is in there, we will deadlock taking the TLB miss over and over, never satisfying the miss.
Just exit early from update_mmu_cache() and friends in this situation.
Based upon a report and patch from Christopher Alexander Tobias Schulze.
Signed-off-by: David S. Miller <davem@davemloft.net> 18f38132 Mon Aug 04 18:34:01 CDT 2014 David S. Miller <davem@davemloft.net> sparc64: Do not insert non-valid PTEs into the TSB hash table. The assumption was that update_mmu_cache() (and the equivalent for PMDs) would only be called when the PTE being installed will be accessible by the user. This is not true for code paths originating from remove_migration_pte(). There are dire consequences for placing a non-valid PTE into the TSB. The TLB miss frramework assumes thatwhen a TSB entry matches we can just load it into the TLB and return from the TLB miss trap. So if a non-valid PTE is in there, we will deadlock taking the TLB miss over and over, never satisfying the miss. Just exit early from update_mmu_cache() and friends in this situation. Based upon a report and patch from Christopher Alexander Tobias Schulze. Signed-off-by: David S. Miller <davem@davemloft.net>
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