From: Nicholas Piggin <npiggin@gmail•com>
To: linuxppc-dev@lists•ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail•com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux•vnet.ibm.com>,
Florian Weimer <fweimer@redhat•com>
Subject: [PATCH 3/5] powerpc/64s/hash: Fix fork() with 512TB process address space
Date: Mon, 6 Nov 2017 21:03:13 +1100 [thread overview]
Message-ID: <20171106100315.29720-4-npiggin@gmail.com> (raw)
In-Reply-To: <20171106100315.29720-1-npiggin@gmail.com>
Hash unconditionally resets the addr_limit to default (128TB) when
the mm context is initialised. If a process has > 128TB mappings when
it forks, the child will not get the 512TB addr_limit, so accesses to
valid > 128TB mappings will fail in the child.
Fix this by only resetting the addr_limit to default if it was 0. Non
zero indicates it was duplicated from the parent (0 means exec()).
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
Fixes: f4ea6dcb08 ("powerpc/mm: Enable mappings above 128TB")
Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
---
arch/powerpc/mm/mmu_context_book3s64.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
index 05e15386d4cb..b94fb62e60fd 100644
--- a/arch/powerpc/mm/mmu_context_book3s64.c
+++ b/arch/powerpc/mm/mmu_context_book3s64.c
@@ -93,11 +93,11 @@ static int hash__init_new_context(struct mm_struct *mm)
return index;
/*
- * We do switch_slb() early in fork, even before we setup the
- * mm->context.addr_limit. Default to max task size so that we copy the
- * default values to paca which will help us to handle slb miss early.
+ * In the case of exec, use the default limit,
+ * otherwise inherit it from the mm we are duplicating.
*/
- mm->context.addr_limit = DEFAULT_MAP_WINDOW_USER64;
+ if (!mm->context.addr_limit)
+ mm->context.addr_limit = DEFAULT_MAP_WINDOW_USER64;
/*
* The old code would re-promote on fork, we don't do that when using
--
2.15.0
next prev parent reply other threads:[~2017-11-06 10:03 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-06 10:03 [PATCH 0/5] VA allocator fixes Nicholas Piggin
2017-11-06 10:03 ` [PATCH 1/5] powerpc/64s/hash: Fix 128TB-512TB virtual address boundary case allocation Nicholas Piggin
2017-11-06 10:38 ` Aneesh Kumar K.V
2017-11-06 10:54 ` Nicholas Piggin
2017-11-06 11:05 ` Aneesh Kumar K.V
2017-11-06 11:21 ` Nicholas Piggin
2017-11-07 2:00 ` Aneesh Kumar K.V
2017-11-07 2:03 ` Nicholas Piggin
2017-11-06 10:03 ` [PATCH 2/5] powerpc/64s/hash: Allow MAP_FIXED allocations to cross 128TB boundary Nicholas Piggin
2017-11-06 10:44 ` Aneesh Kumar K.V
2017-11-06 11:55 ` Nicholas Piggin
2017-11-07 2:28 ` Michael Ellerman
2017-11-07 2:52 ` Nicholas Piggin
2017-11-06 10:03 ` Nicholas Piggin [this message]
2017-11-06 10:44 ` [PATCH 3/5] powerpc/64s/hash: Fix fork() with 512TB process address space Aneesh Kumar K.V
2017-11-06 10:03 ` [PATCH 4/5] powerpc/64s/radix: Fix 128TB-512TB virtual address boundary case allocation Nicholas Piggin
2017-11-06 11:14 ` Aneesh Kumar K.V
2017-11-06 11:42 ` Nicholas Piggin
2017-11-06 10:03 ` [PATCH 5/5] powerpc/64s: mm_context.addr_limit is only used on hash Nicholas Piggin
2017-11-06 15:16 ` [PATCH 0/5] VA allocator fixes Florian Weimer
2017-11-07 0:06 ` Nicholas Piggin
2017-11-07 1:59 ` Aneesh Kumar K.V
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