This is a note to let you know that I've just added the patch titled
vmalloc: fix __GFP_HIGHMEM usage for vmalloc_32 on 32b systems
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vmalloc-fix-__gfp_highmem-usage-for-vmalloc_32-on-32b-systems.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 698d0831ba87b92ae10b15e8203cfd59f5a59a35 Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@xxxxxxxx>
Date: Wed, 21 Feb 2018 14:46:01 -0800
Subject: vmalloc: fix __GFP_HIGHMEM usage for vmalloc_32 on 32b systems
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From: Michal Hocko <mhocko@xxxxxxxx>
commit 698d0831ba87b92ae10b15e8203cfd59f5a59a35 upstream.
Kai Heng Feng has noticed that BUG_ON(PageHighMem(pg)) triggers in
drivers/media/common/saa7146/saa7146_core.c since 19809c2da28a ("mm,
vmalloc: use __GFP_HIGHMEM implicitly").
saa7146_vmalloc_build_pgtable uses vmalloc_32 and it is reasonable to
expect that the resulting page is not in highmem. The above commit
aimed to add __GFP_HIGHMEM only for those requests which do not specify
any zone modifier gfp flag. vmalloc_32 relies on GFP_VMALLOC32 which
should do the right thing. Except it has been missed that GFP_VMALLOC32
is an alias for GFP_KERNEL on 32b architectures. Thanks to Matthew to
notice this.
Fix the problem by unconditionally setting GFP_DMA32 in GFP_VMALLOC32
for !64b arches (as a bailout). This should do the right thing and use
ZONE_NORMAL which should be always below 4G on 32b systems.
Debugged by Matthew Wilcox.
[akpm@xxxxxxxxxxxxxxxxxxxx: coding-style fixes]
Link: http://lkml.kernel.org/r/20180212095019.GX21609@xxxxxxxxxxxxxx
Fixes: 19809c2da28a ("mm, vmalloc: use __GFP_HIGHMEM implicitly”)
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Reported-by: Kai Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Laura Abbott <labbott@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1943,11 +1943,15 @@ void *vmalloc_exec(unsigned long size)
}
#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
-#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
+#define GFP_VMALLOC32 (GFP_DMA32 | GFP_KERNEL)
#elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
-#define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL
+#define GFP_VMALLOC32 (GFP_DMA | GFP_KERNEL)
#else
-#define GFP_VMALLOC32 GFP_KERNEL
+/*
+ * 64b systems should always have either DMA or DMA32 zones. For others
+ * GFP_DMA32 should do the right thing and use the normal zone.
+ */
+#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
#endif
/**
Patches currently in stable-queue which might be from mhocko@xxxxxxxx are
queue-4.15/vmalloc-fix-__gfp_highmem-usage-for-vmalloc_32-on-32b-systems.patch