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From: Yinghai Lu <yinghai@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
	"H. Peter Anvin" <hpa@zytor.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jan Kiszka <jan.kiszka@web.de>,
	Jason Wessel <jason.wessel@windriver.com>,
	Borislav Petkov <bp@alien8.de>,
	linux-kernel@vger.kernel.org, Yinghai Lu <yinghai@kernel.org>
Subject: [PATCH 01/35] x86, mm: Fix page table early allocation offset checking
Date: Thu, 24 Jan 2013 12:19:42 -0800	[thread overview]
Message-ID: <1359058816-7615-2-git-send-email-yinghai@kernel.org> (raw)
In-Reply-To: <1359058816-7615-1-git-send-email-yinghai@kernel.org>

During debugging loading kernel above 4G, found that one page is not used
in pre-allocated BRK area for early page allocation.
pgt_buf_top is address that can not be used, so should check if that new
end is above that top, otherwise last page will not be used.

Fix that checking and also add print out for allocation from pre-allocated
BRK area to catch possible bugs later.

But after we get back that page for pgt, it tiggers one bug in pgt allocation
with xen: We need to avoid to use page as pgt to map range that is
overlapping with that pgt page.

Add checking about overlapping, when it happens, use memblock allocation
instead.  That fixes crash on Xen PV guest with 2G that Stefan found.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 arch/x86/mm/init.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 6f85de8..78d1ef3 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -25,6 +25,8 @@ static unsigned long __initdata pgt_buf_top;
 
 static unsigned long min_pfn_mapped;
 
+static bool __initdata can_use_brk_pgt = true;
+
 /*
  * Pages returned are already directly mapped.
  *
@@ -47,7 +49,7 @@ __ref void *alloc_low_pages(unsigned int num)
 						__GFP_ZERO, order);
 	}
 
-	if ((pgt_buf_end + num) >= pgt_buf_top) {
+	if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
 		unsigned long ret;
 		if (min_pfn_mapped >= max_pfn_mapped)
 			panic("alloc_low_page: ran out of memory");
@@ -61,6 +63,8 @@ __ref void *alloc_low_pages(unsigned int num)
 	} else {
 		pfn = pgt_buf_end;
 		pgt_buf_end += num;
+		printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
+			pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
 	}
 
 	for (i = 0; i < num; i++) {
@@ -370,8 +374,15 @@ static unsigned long __init init_range_memory_mapping(
 		if (start >= end)
 			continue;
 
+		/*
+		 * if it is overlapping with brk pgt, we need to
+		 * alloc pgt buf from memblock instead.
+		 */
+		can_use_brk_pgt = max(start, (u64)pgt_buf_end<<PAGE_SHIFT) >=
+				    min(end, (u64)pgt_buf_top<<PAGE_SHIFT);
 		init_memory_mapping(start, end);
 		mapped_ram_size += end - start;
+		can_use_brk_pgt = true;
 	}
 
 	return mapped_ram_size;
-- 
1.7.10.4


  reply	other threads:[~2013-01-24 20:21 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-24 20:19 [PATCH 00/35] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G Yinghai Lu
2013-01-24 20:19 ` Yinghai Lu [this message]
2013-01-30  1:20   ` [tip:x86/mm2] x86, mm: Fix page table early allocation offset checking tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 02/35] x86: Handle multiple exactmaps and out of order exactmap Yinghai Lu
2013-01-24 20:19 ` [PATCH 03/35] x86, mm: Introduce memmap=reserveram Yinghai Lu
2013-01-24 20:19 ` [PATCH 04/35] x86: Clean up e820 add kernel range Yinghai Lu
2013-01-24 23:21   ` Jacob Shin
2013-01-30  1:21   ` [tip:x86/mm2] x86: Factor out e820_add_kernel_range() tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 05/35] x86, 64bit, mm: Make pgd next calculation consistent with pud/pmd Yinghai Lu
2013-01-30  1:22   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 06/35] x86, realmode: Set real_mode permissions early Yinghai Lu
2013-01-30  1:23   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 07/35] x86, 64bit, mm: Add generic kernel/ident mapping helper Yinghai Lu
2013-01-30  1:24   ` [tip:x86/mm2] x86, 64bit, mm: Add generic kernel/ ident " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 08/35] x86, 64bit: Copy zero-page early Yinghai Lu
2013-01-30  1:25   ` [tip:x86/mm2] x86, 64bit: Copy struct boot_params early tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 09/35] x86, 64bit, realmode: Use init_level4_pgt to set trapmoline_pgd directly Yinghai Lu
2013-01-30  1:27   ` [tip:x86/mm2] x86, 64bit, realmode: Use init_level4_pgt to set trampoline_pgd directly tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 10/35] x86, realmode: Separate real_mode reserve and setup Yinghai Lu
2013-01-30  1:28   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 11/35] x86, 64bit: early #PF handler set page table Yinghai Lu
2013-01-30  1:29   ` [tip:x86/mm2] x86, 64bit: Use a #PF handler to materialize early mappings on demand tip-bot for H. Peter Anvin
2013-01-24 20:19 ` [PATCH 12/35] x86, 64bit: #PF handler set page to cover only 2M per #PF Yinghai Lu
2013-01-30  1:30   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 13/35] x86, 64bit: Don't set max_pfn_mapped wrong value early on native path Yinghai Lu
2013-01-30  1:31   ` [tip:x86/mm2] x86, 64bit: Don' t " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 14/35] x86: Merge early_reserve_initrd for 32bit and 64bit Yinghai Lu
2013-01-30  1:32   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 15/35] x86: Add get_ramdisk_image/size() Yinghai Lu
2013-01-30  1:34   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 16/35] x86, boot: Add get_cmd_line_ptr() Yinghai Lu
2013-01-30  1:35   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 17/35] x86, boot: Move checking of cmd_line_ptr out of common path Yinghai Lu
2013-01-30  1:36   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:19 ` [PATCH 18/35] x86, boot: Pass cmd_line_ptr with unsigned long instead Yinghai Lu
2013-01-30  1:37   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 19/35] x86, boot: Move verify_cpu.S and no_longmode down Yinghai Lu
2013-01-30  1:38   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 20/35] x86, boot: Move lldt/ltr out of 64bit code section Yinghai Lu
2013-01-30  1:39   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 21/35] x86, kexec: Remove 1024G limitation for kexec buffer on 64bit Yinghai Lu
2013-01-30  1:40   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 22/35] x86, kexec: Set ident mapping for kernel that is above max_pfn Yinghai Lu
2013-01-30  1:42   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 23/35] x86, kexec: Replace ident_mapping_init and init_level4_page Yinghai Lu
2013-01-30  1:43   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 24/35] x86, kexec, 64bit: Only set ident mapping for ram Yinghai Lu
2013-01-30  1:44   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 25/35] x86, boot: Add fields to support load bzImage and ramdisk above 4G Yinghai Lu
2013-01-28  0:07   ` [tip:x86/boot] x86, boot: Define the 2.12 bzImage boot protocol tip-bot for H. Peter Anvin
2013-01-29  9:48   ` [tip:x86/boot] x86, boot: Sanitize boot_params if not zeroed on creation tip-bot for H. Peter Anvin
2013-01-30  1:45   ` [tip:x86/mm2] x86, boot: enable support load bzImage and ramdisk above 4G tip-bot for Yinghai Lu
2013-01-30  1:54     ` Yinghai Lu
2013-01-30  2:18       ` H. Peter Anvin
2013-01-30  3:47   ` [tip:x86/mm2] x86, boot: Support loading bzImage, boot_params " tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 26/35] x86, boot: Update comments about entries for 64bit image Yinghai Lu
2013-01-30  1:46   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-30  3:48   ` tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 27/35] x86, boot: Not need to check setup_header version for setup_data Yinghai Lu
2013-01-30  1:47   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-30  3:49   ` tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 28/35] memblock: Add memblock_mem_size() Yinghai Lu
2013-01-30  1:49   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-30  3:50   ` tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 29/35] x86, kdump: Remove crashkernel range find limit for 64bit Yinghai Lu
2013-01-30  1:50   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-30  3:51   ` tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 30/35] x86: Add Crash kernel low reservation Yinghai Lu
2013-01-30  1:51   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-02-07  5:14     ` Rob Landley
2013-02-07  6:39       ` Yinghai Lu
2013-01-30  3:52   ` tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 31/35] x86: Merge early kernel reserve for 32bit and 64bit Yinghai Lu
2013-01-30  1:52   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-30  3:53   ` tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 32/35] x86, 64bit, mm: Mark data/bss/brk to nx Yinghai Lu
2013-01-30  1:53   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-30  3:55   ` tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 33/35] x86, 64bit, mm: hibernate use generic mapping_init Yinghai Lu
2013-01-24 22:50   ` Rafael J. Wysocki
2013-01-30  1:54   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-30  3:56   ` tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 34/35] mm: Add alloc_bootmem_low_pages_nopanic() Yinghai Lu
2013-01-30  1:56   ` [tip:x86/mm2] " tip-bot for Yinghai Lu
2013-01-30  3:57   ` tip-bot for Yinghai Lu
2013-01-24 20:20 ` [PATCH 35/35] x86: Don't panic if can not alloc buffer for swiotlb Yinghai Lu
2013-01-25 16:47   ` Konrad Rzeszutek Wilk
2013-01-30  1:57   ` [tip:x86/mm2] x86: Don' t " tip-bot for Yinghai Lu
2013-01-30  3:58   ` tip-bot for Yinghai Lu

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