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| author | Kevin Cernekee <cernekee@gmail.com> | 2010-05-30 11:32:51 +0400 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2011-07-25 20:26:52 +0400 |
| commit | b6da0ffb09ad4468e6749488909f04f1efac5de3 (patch) | |
| tree | c2c3f5f2a00531809c309fffb9ee9ab28bce44a8 /arch/mips/mm | |
| parent | e36863a550da44595b155c6b86ff46b50cbff5c0 (diff) | |
| download | linux-b6da0ffb09ad4468e6749488909f04f1efac5de3.tar.xz | |
MIPS: pfn_valid() is broken on low memory HIGHMEM systems
pfn_valid() compares the PFN to max_mapnr:
__pfn >= min_low_pfn && __pfn < max_mapnr;
On HIGHMEM kernels, highend_pfn is used to set the value of max_mapnr.
Unfortunately, highend_pfn is left at zero if the system does not
actually have enough RAM to reach into the HIGHMEM range. This causes
pfn_valid() to always return false, and when debug checks are enabled
the kernel will fail catastrophically:
Memory: 22432k/32768k available (2249k kernel code, 10336k reserved, 653k data, 1352k init, 0k highmem)
NR_IRQS:128
kfree_debugcheck: out of range ptr 81c02900h.
Kernel bug detected[#1]:
Cpu 0
$ 0 : 00000000 10008400 00000034 00000000
$ 4 : 8003e160 802a0000 8003e160 00000000
$ 8 : 00000000 0000003e 00000747 00000747
...
On such a configuration, max_low_pfn should be used to set max_mapnr.
This was seen on 2.6.34.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1992/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/mm')
| -rw-r--r-- | arch/mips/mm/init.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 1aadeb42c5a5..11689e1a2924 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -368,7 +368,7 @@ void __init mem_init(void) #ifdef CONFIG_DISCONTIGMEM #error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet" #endif - max_mapnr = highend_pfn; + max_mapnr = highend_pfn ? highend_pfn : max_low_pfn; #else max_mapnr = max_low_pfn; #endif |