[PATCH] powerpc/mm/32: Fix pgtable_page_dtor call

Commit 667416f38554 ("powerpc/mm: Fix kernel crash on page table free")
added a call for pgtable_page_dtor in the rcu page table free routine. We missed
the fact that for 32 bit platforms we did call the 'dtor' early. Drop the extra
call for pgtable_page_dtor. We remove the call from __pte_free_tlb so that we
do the page table free and 'dtor' call together. This should help when we
switch these platforms to pte fragments.

Fixes: 667416f38554 ("powerpc/mm: Fix kernel crash on page table free")
Reported-by: Christophe Leroy <redacted>
Signed-off-by: Aneesh Kumar K.V <redacted>
---
 arch/powerpc/include/asm/book3s/32/pgalloc.h | 1 -
 arch/powerpc/include/asm/nohash/32/pgalloc.h | 1 -
 2 files changed, 2 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/32/pgalloc.h b/arch/powerpc/include/asm/book3s/32/pgalloc.h
index e4633803fe43..82e44b1a00ae 100644
--- a/arch/powerpc/include/asm/book3s/32/pgalloc.h
+++ b/arch/powerpc/include/asm/book3s/32/pgalloc.h

@@ -138,7 +138,6 @@ static inline void pgtable_free_tlb(struct mmu_gather *tlb,
 static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
 				  unsigned long address)
 {
-	pgtable_page_dtor(table);
 	pgtable_free_tlb(tlb, page_address(table), 0);
 }
 #endif /* _ASM_POWERPC_BOOK3S_32_PGALLOC_H */

diff --git a/arch/powerpc/include/asm/nohash/32/pgalloc.h b/arch/powerpc/include/asm/nohash/32/pgalloc.h
index 9de40eb614da..8825953c225b 100644
--- a/arch/powerpc/include/asm/nohash/32/pgalloc.h
+++ b/arch/powerpc/include/asm/nohash/32/pgalloc.h

@@ -140,7 +140,6 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
 				  unsigned long address)
 {
 	tlb_flush_pgtable(tlb, address);
-	pgtable_page_dtor(table);
 	pgtable_free_tlb(tlb, page_address(table), 0);
 }
 #endif /* _ASM_POWERPC_PGALLOC_32_H */

-- 
2.17.1

On Mon, 2018-06-25 at 08:15:09 UTC, "Aneesh Kumar K.V" wrote:

Commit 667416f38554 ("powerpc/mm: Fix kernel crash on page table free")
added a call for pgtable_page_dtor in the rcu page table free routine. We missed
the fact that for 32 bit platforms we did call the 'dtor' early. Drop the extra
call for pgtable_page_dtor. We remove the call from __pte_free_tlb so that we
do the page table free and 'dtor' call together. This should help when we
switch these platforms to pte fragments.

Fixes: 667416f38554 ("powerpc/mm: Fix kernel crash on page table free")
Reported-by: Christophe Leroy <redacted>
Signed-off-by: Aneesh Kumar K.V <redacted>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/941c06d58503b9f2718b20bc45ee7f

cheers