Messages in this thread Patch in this message | | | Date | Thu, 16 Dec 2010 16:39:43 -0800 | From | Yinghai Lu <> | Subject | Re: kdump broken on 2.6.37-rc4 |
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On 12/16/2010 03:49 PM, Yinghai Lu wrote: > On 12/16/2010 03:30 PM, Yinghai Lu wrote: >> On 12/16/2010 11:58 AM, H. Peter Anvin wrote: >>> On 12/16/2010 09:28 AM, Yinghai Lu wrote: >>>> >>>> the brk is complaining if i change that to >>>> >>>> if (end > ((-__PAGE_OFFSET-(128 <<20)-1) & 0x7fffffff)) >>>> error("Destination address too large"); >>>> >>>> brk is complaining when try to get more for dmi ... >>>> ... >>>> I'm in purgatory >>>> bootconsole [uart0] enabled >>>> Kernel Layout: >>>> .text: [0x2e000000-0x2e3f08ca] >>>> .rodata: [0x2e3f2000-0x2e5a2fff] >>>> .data: [0x2e5a3000-0x2e5f6467] >>>> .init: [0x2e5f7000-0x2e670fff] >>>> .bss: [0x2e675000-0x2e76ffff] >>>> .brk: [0x2e770000-0x2e894fff] >>>> memblock_x86_reserve_range: [0x00001000-0x00001fff] EX TRAMPOLINE >>>> memblock_x86_reserve_range: [0x2e000000-0x2e76ffff] TEXT DATA BSS >>>> memblock_x86_reserve_range: [0x35bdd000-0x35f49fff] RAMDISK >>>> memblock_x86_reserve_range: [0x0009c800-0x000fffff] * BIOS reserved >>>> Initializing cgroup subsys cpuset >>>> Initializing cgroup subsys cpu >>>> Linux version 2.6.37-rc5-tip+ (root@mpk12-3214-189-181) (gcc version 4.4.4 20100726 (Red Hat 4.4.4-13) (GCC) ) #4 SMP Wed Dec 15 11:04:32 PST 2010 >>>> KERNEL supported cpus: >>>> Intel GenuineIntel >>>> AMD AuthenticAMD >>>> NSC Geode by NSC >>>> Cyrix CyrixInstead >>>> Centaur CentaurHauls >>>> Transmeta GenuineTMx86 >>>> Transmeta TransmetaCPU >>>> UMC UMC UMC UMC >>>> BIOS-provided physical RAM map: >>>> BIOS-e820: [0x00000000000100-0x0000000009c7ff] (usable) >>>> BIOS-e820: [0x0000000009c800-0x0000000009ffff] (reserved) >>>> BIOS-e820: [0x000000000e0000-0x000000000fffff] (reserved) >>>> BIOS-e820: [0x00000000100000-0x0000007ff9ffff] (usable) >>>> BIOS-e820: [0x0000007ffae000-0x0000007ffaffff] (usable) >>>> BIOS-e820: [0x0000007ffb0000-0x0000007ffbdfff] (ACPI data) >>>> BIOS-e820: [0x0000007ffbe000-0x0000007ffeffff] (ACPI NVS) >>>> BIOS-e820: [0x0000007fff0000-0x0000007fffffff] (reserved) >>>> BIOS-e820: [0x000000e0000000-0x000000efffffff] (reserved) >>>> BIOS-e820: [0x000000fec00000-0x000000fec00fff] (reserved) >>>> BIOS-e820: [0x000000fee00000-0x000000feefffff] (reserved) >>>> BIOS-e820: [0x000000ff700000-0x000000ffffffff] (reserved) >>>> last_pfn = 0x7ffb0 max_arch_pfn = 0x1000000 >>>> NX (Execute Disable) protection: active >>>> user-defined physical RAM map: >>>> user: [0x00000000000000-0x0000000009ffff] (usable) >>>> user: [0x0000002e000000-0x00000035f59fff] (usable) >>>> user: [0x0000007ffb0000-0x0000007ffeffff] (ACPI data) >>>> DMI present. >>>> BUG: Int 6: CR2 (null) >>>> EDI 00000019 ESI ff940c18 EBP (null) ESP ee5a5e84 >>>> EBX ee5cfb68 EDX 00000006 ECX 00000019 EAX ee8e6019 >>>> err (null) EIP ee5fb4dd CS 00000060 flg 00010002 >>>> Stack: 00000019 ee62bf45 ff942000 00000563 00000001 ff940c00 000018c7 ee62bf83 >>>> ff940c00 ee62c063 80000000 ee3e6f2f ee50a3c0 ee5a5ed4 ff940c00 ff940c43 >>>> 000018c7 (null) ee3173d4 000018c8 0000007f ff940c00 ff90b1bf ee5a5f18 >>>> Pid: 0, comm: swapper Not tainted 2.6.37-rc5-tip+ #4 >>>> Call Trace: >>>> [<ee3dd1d5>] ? hlt_loop+0x0/0x3 >>>> [<ee5fb4dd>] ? extend_brk+0x31/0x44 >>> >>> I'm assuming it bails due to: >>> >>> BUG_ON((char *)(_brk_end + size) > __brk_limit); >>> >>> ... could you find out what _brk_end and __brk_limit are? >> >> void __init print_kernel_layout(void) >> { >> printk("Kernel Layout:\n"); >> printk(" .text: [%#010lx-%#010lx]\n", __pa_symbol(&_text), __pa_symbol(&_etext) - 1); >> printk(".rodata: [%#010lx-%#010lx]\n", __pa_symbol(&__start_rodata), __pa_symbol(&__end_rodata) - 1); >> printk(" .data: [%#010lx-%#010lx]\n", __pa_symbol(&_sdata), __pa_symbol(&_edata) - 1); >> printk(" .init: [%#010lx-%#010lx]\n", __pa_symbol(&__init_begin), __pa_symbol(&__init_end) - 1); >> printk(" .bss: [%#010lx-%#010lx]\n", __pa_symbol(&__bss_start), __pa_symbol(&__bss_stop) - 1); >> printk(" .brk: [%#010lx-%#010lx]\n", __pa_symbol(&__brk_base), __pa_symbol(&__brk_limit) - 1); >> } >> >>>> Kernel Layout: >>>> .text: [0x2e000000-0x2e3f08ca] >>>> .rodata: [0x2e3f2000-0x2e5a2fff] >>>> .data: [0x2e5a3000-0x2e5f6467] >>>> .init: [0x2e5f7000-0x2e670fff] >>>> .bss: [0x2e675000-0x2e76ffff] >>>> .brk: [0x2e770000-0x2e894fff] >> >> DMI present. >> _brk_end: ee8e6000, __brk_limit: ee895000 >> > > looks like in arch/x86/kernel/head_32.S > will put page_table in _brk.... > > if the whole range is some high, it will use more buffer in _brk for ... > > brk pre-calucation could be wrong and too small.
32bit have assume KERNEL_IMAGE_SIZE is 512M arch/x86/include/asm/page_32_types.h:#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024) arch/x86/include/asm/page_64_types.h:#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024) arch/x86/kernel/head64.c: BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE); arch/x86/kernel/head64.c: BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE); arch/x86/kernel/head64.c: max_pfn_mapped = KERNEL_IMAGE_SIZE >> PAGE_SHIFT; arch/x86/kernel/head_32.S: * (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE) arch/x86/kernel/head_32.S: * (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE) arch/x86/kernel/head_32.S: * KERNEL_IMAGE_SIZE should be greater than pa(_end) arch/x86/kernel/head_32.S:KERNEL_PAGES = (KERNEL_IMAGE_SIZE + MAPPING_BEYOND_END)>>PAGE_SHIFT
and use that to estimate BRK size.
so we could change the BRK calculating code to handle 896M or just limit crashkernel for 32bit to 512M...
handle 896M one:
--- arch/x86/boot/compressed/misc.c | 2 +- arch/x86/kernel/head_32.S | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-)
Index: linux-2.6/arch/x86/boot/compressed/misc.c =================================================================== --- linux-2.6.orig/arch/x86/boot/compressed/misc.c +++ linux-2.6/arch/x86/boot/compressed/misc.c @@ -365,7 +365,7 @@ asmlinkage void decompress_kernel(void * if (heap > 0x3fffffffffffUL) error("Destination address too large"); #else - if (heap > ((-__PAGE_OFFSET-(512<<20)-1) & 0x7fffffff)) + if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff)) error("Destination address too large"); #endif #ifndef CONFIG_RELOCATABLE Index: linux-2.6/arch/x86/kernel/head_32.S =================================================================== --- linux-2.6.orig/arch/x86/kernel/head_32.S +++ linux-2.6/arch/x86/kernel/head_32.S @@ -68,8 +68,10 @@ MAPPING_BEYOND_END = \ * Worst-case size of the kernel mapping we need to make: * the worst-case size of the kernel itself, plus the extra we need * to map for the linear map. + * to make crashkernel bzImage to stay high, make it map to 896M + * but it will be claimed back when brk is concluded. So no wasting. */ -KERNEL_PAGES = (KERNEL_IMAGE_SIZE + MAPPING_BEYOND_END)>>PAGE_SHIFT +KERNEL_PAGES = (KERNEL_IMAGE_SIZE + (384<<20) + MAPPING_BEYOND_END)>>PAGE_SHIFT INIT_MAP_SIZE = PAGE_TABLE_SIZE(KERNEL_PAGES) * PAGE_SIZE_asm RESERVE_BRK(pagetables, INIT_MAP_SIZE)
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