Messages in this thread Patch in this message | | | Date | Mon, 28 May 2012 05:29:11 -0700 (PDT) | From | Zhenzhong Duan <> | Subject | [PATCH] Fix an overflow in range_to_mtrr func |
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When boot x86_64 kernel on sun G5+ with 4T mem, see an overflow in mtrr cleanup as below.
*BAD*gran_size: 2G chunk_size: 2G num_reg: 10 lose cover RAM: -18014398505283592M
This is because 1<<31 sign extended. Use explicit type conversion to force a 64bit constant to fix it. Useful for mem larger than or equal to 4T.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> --- arch/x86/kernel/cpu/mtrr/cleanup.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c index ac140c7..853a4c6 100644 --- a/arch/x86/kernel/cpu/mtrr/cleanup.c +++ b/arch/x86/kernel/cpu/mtrr/cleanup.c @@ -266,7 +266,7 @@ range_to_mtrr(unsigned int reg, unsigned long range_startk, if (align > max_align) align = max_align; - sizek = 1 << align; + sizek = (unsigned long)1 << align; if (debug_print) { char start_factor = 'K', size_factor = 'K'; unsigned long start_base, size_base; -- 1.7.3
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