From 40823f737e5bd186a1156fb1c28f360260e1e084 Mon Sep 17 00:00:00 2001 From: Andreas Herrmann Date: Wed, 25 Feb 2009 11:26:18 +0100 Subject: [PATCH] x86: memtest: reuse test patterns when memtest parameter exceeds number of available patterns Impact: fix unexpected behaviour when pattern number is out of range Current implementation provides 4 patterns for memtest. The code doesn't check whether the memtest parameter value exceeds the maximum pattern number. Instead the memtest code pretends to test with non-existing patterns, e.g. when booting with memtest=10 I've observed the following ... early_memtest: pattern num 10 0000001000 - 0000006000 pattern 0 ... 0000001000 - 0000006000 pattern 1 ... 0000001000 - 0000006000 pattern 2 ... 0000001000 - 0000006000 pattern 3 ... 0000001000 - 0000006000 pattern 4 ... 0000001000 - 0000006000 pattern 5 ... 0000001000 - 0000006000 pattern 6 ... 0000001000 - 0000006000 pattern 7 ... 0000001000 - 0000006000 pattern 8 ... 0000001000 - 0000006000 pattern 9 ... But in fact Linux didn't test anything for patterns > 4 as the default case in memtest() is to leave the function. I suggest to use the memtest parameter as the number of tests to be performed and to re-iterate over all existing patterns. Signed-off-by: Andreas Herrmann Signed-off-by: Ingo Molnar --- arch/x86/mm/memtest.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/memtest.c b/arch/x86/mm/memtest.c index 9cab18b0b857..00b8bdc64c3e 100644 --- a/arch/x86/mm/memtest.c +++ b/arch/x86/mm/memtest.c @@ -9,6 +9,8 @@ #include +#define _MAX_MEM_PATTERNS 4 + static void __init memtest(unsigned long start_phys, unsigned long size, unsigned pattern) { @@ -21,6 +23,8 @@ static void __init memtest(unsigned long start_phys, unsigned long size, unsigned long count; unsigned long incr; + pattern = pattern % _MAX_MEM_PATTERNS; + switch (pattern) { case 0: val = 0UL; @@ -110,8 +114,9 @@ void __init early_memtest(unsigned long start, unsigned long end) t_size = end - t_start; printk(KERN_CONT "\n %010llx - %010llx pattern %d", - (unsigned long long)t_start, - (unsigned long long)t_start + t_size, pattern); + (unsigned long long)t_start, + (unsigned long long)t_start + t_size, + pattern % _MAX_MEM_PATTERNS); memtest(t_start, t_size, pattern); -- GitLab