3.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Helge Deller <deller@xxxxxx>
commit ae249b5fa27f9fba25aa59664d4338efc2dd2394 upstream.
With CONFIG_DISCONTIGMEM=y and multiple physical memory areas,
cat /proc/kpageflags triggers this kernel bug:
kernel BUG at arch/parisc/include/asm/mmzone.h:50!
CPU: 2 PID: 7848 Comm: cat Tainted: G D W 3.10.0-rc3-64bit #44
IAOQ[0]: kpageflags_read0x128/0x238
IAOQ[1]: kpageflags_read0x12c/0x238
RP(r2): proc_reg_read0xbc/0x130
Backtrace:
[<00000000402ca2d4>] proc_reg_read0xbc/0x130
[<0000000040235bcc>] vfs_read0xc4/0x1d0
[<0000000040235f0c>] SyS_read0x94/0xf0
[<0000000040105fc0>] syscall_exit0x0/0x14
kpageflags_read() walks through the whole memory, even if some memory
areas are physically not available. So, we should better not BUG on an
unavailable pfn in pfn_to_nid() but just return the expected value -1 or
0.
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/parisc/include/asm/mmzone.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
--- a/arch/parisc/include/asm/mmzone.h
+++ b/arch/parisc/include/asm/mmzone.h
@@ -39,17 +39,14 @@ extern unsigned char pfnnid_map[PFNNID_M
static inline int pfn_to_nid(unsigned long pfn)
{
unsigned int i;
- unsigned char r;
if (unlikely(pfn_is_io(pfn)))
return 0;
i = pfn >> PFNNID_SHIFT;
BUG_ON(i >= ARRAY_SIZE(pfnnid_map));
- r = pfnnid_map[i];
- BUG_ON(r == 0xff);
- return (int)r;
+ return (int)pfnnid_map[i];
}
static inline int pfn_valid(int pfn)
--
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