linux-kernel - [PATCH] [5/8] Fix logic error in 64bit memory hotadd

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 11 Feb 2008 10:34:33 +0100 (CET)
From:	Andi Kleen <ak@...e.de>
To:	tglx@...utronix.de, mingo@...e.hu, linux-kernel@...r.kernel.org
Subject: [PATCH] [5/8] Fix logic error in 64bit memory hotadd


The memory hotadd code assumes that the pud always exists already, but 
that might be not true. Allocate it if it isn't there.

Signed-off-by: Andi Kleen <ak@...e.de>

---
 arch/x86/mm/init_64.c |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

Index: linux/arch/x86/mm/init_64.c
===================================================================
--- linux.orig/arch/x86/mm/init_64.c
+++ linux/arch/x86/mm/init_64.c
@@ -432,17 +432,22 @@ void __init_refok init_memory_mapping(un
 		unsigned long pud_phys;
 		pud_t *pud;
 
-		if (after_bootmem)
+		if (after_bootmem) {
 			pud = pud_offset(pgd, start & PGDIR_MASK);
-		else
+			if (!pud_present(*pud)) {
+				pud = (pud_t *)get_zeroed_page(GFP_ATOMIC);
+				if (!pud)
+					panic("Out of memory");
+			}
+			pud_phys = __pa(pud);
+		} else
 			pud = alloc_low_page(&pud_phys);
 
 		next = start + PGDIR_SIZE;
 		if (next > end)
 			next = end;
 		phys_pud_init(pud, __pa(start), __pa(next));
-		if (!after_bootmem)
-			set_pgd(pgd_offset_k(start), mk_kernel_pgd(pud_phys));
+		set_pgd(pgd_offset_k(start), mk_kernel_pgd(pud_phys));
 		unmap_low_page(pud);
 	}
 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/