linux-kernel - [PATCH] Xen: Fix pte unpin BUG when !CONFIG

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-next>] [day] [month] [year] [list]

Date:	Tue,  9 Sep 2008 12:25:08 +0100
From:	Alex Nixon <alex.nixon@...rix.com>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:	Alex Nixon <alex.nixon@...rix.com>,
	Jeremy Fitzhardinge <jeremy@...p.org>,
	Ingo Molnar <mingo@...e.hu>
Subject: [PATCH] Xen: Fix pte unpin BUG when !CONFIG_SMP

We still need to pin PTEs, even if there are no PTE locks.  Otherwise we'll BUG whenever there aren't PTE locks (i.e. whenever NR_CPUS < CONFIG_SPLIT_PTLOCK_CPUS), as we try to unpin PTEs which were never pinned in the first place.

Signed-off-by: Alex Nixon <alex.nixon@...rix.com>
Cc: Jeremy Fitzhardinge <jeremy@...p.org>
Cc: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/xen/mmu.c |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index f5af913..1239bda 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -819,9 +819,10 @@ static int xen_pin_page(struct page *page, enum pt_level level)
 					pfn_pte(pfn, PAGE_KERNEL_RO),
 					level == PT_PGD ? UVMF_TLB_FLUSH : 0);
 
-		if (ptl) {
+		if (level == PT_PTE)
 			xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
 
+		if (ptl) {
 			/* Queue a deferred unlock for when this batch
 			   is completed. */
 			xen_mc_callback(xen_pte_unlock, ptl);
@@ -924,9 +925,7 @@ static int xen_unpin_page(struct page *page, enum pt_level level)
 		 */
 		if (level == PT_PTE) {
 			ptl = xen_pte_lock(page);
-
-			if (ptl)
-				xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
+			xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
 		}
 
 		mcs = __xen_mc_entry(0);
-- 
1.5.4.3

--
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/