Messages in this thread Patch in this message |  | | Date | Mon, 16 Jun 2008 12:25:28 +0800 | From | Dave Young <> | Subject | [PATCH] kernel parameter vmalloc size fix |
| |
booting kernel with vmalloc=[any size<=16m] will oops.
It's due to the vm area hole.
In include/asm-x86/pgtable_32.h: #define VMALLOC_OFFSET (8 * 1024 * 1024) #define VMALLOC_START (((unsigned long)high_memory + 2 * VMALLOC_OFFSET - 1) \ & ~(VMALLOC_OFFSET - 1))
BUG_ON in arch/x86/mm/init_32.c will be triggered: BUG_ON((unsigned long)high_memory > VMALLOC_START);
Fixed by return -EINVAL for invalid parameter
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Documentation/kernel-parameters.txt | 3 ++- arch/x86/kernel/setup_32.c | 11 +++++++++-- 2 files changed, 11 insertions(+), 3 deletions(-)
diff -upr linux/Documentation/kernel-parameters.txt linux.new/Documentation/kernel-parameters.txt --- linux/Documentation/kernel-parameters.txt 2008-06-16 11:30:29.000000000 +0800 +++ linux.new/Documentation/kernel-parameters.txt 2008-06-16 11:43:01.000000000 +0800 @@ -2139,7 +2139,8 @@ and is between 256 and 4096 characters. size of <nn>. This can be used to increase the minimum size (128MB on x86). It can also be used to decrease the size and leave more room for directly - mapped kernel RAM. + mapped kernel RAM. Note that the size must be bigger + than 16M now on i386 due to the memory hole. vmhalt= [KNL,S390] Perform z/VM CP command after system halt. Format: <command> diff -upr linux/arch/x86/kernel/setup_32.c linux.new/arch/x86/kernel/setup_32.c --- linux/arch/x86/kernel/setup_32.c 2008-06-16 11:28:51.000000000 +0800 +++ linux.new/arch/x86/kernel/setup_32.c 2008-06-16 11:43:35.000000000 +0800 @@ -305,15 +305,22 @@ early_param("highmem", parse_highmem); /* * vmalloc=size forces the vmalloc area to be exactly 'size' - * bytes. This can be used to increase (or decrease) the + * bytes. Now size must be bigger than 16m due to the memory hole. + * This can be used to increase (or decrease) the * vmalloc area - the default is 128m. */ static int __init parse_vmalloc(char *arg) { + unsigned int v; + if (!arg) return -EINVAL; - __VMALLOC_RESERVE = memparse(arg, &arg); + v = memparse(arg, &arg); + if (v <= 2 * VMALLOC_OFFSET) + return -EINVAL; + __VMALLOC_RESERVE = v; + return 0; } early_param("vmalloc", parse_vmalloc);
|  |