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From: Andres Lagar-Cavilla <andres@lagarcavilla.org>
To: xen-devel@lists.xensource.com
Cc: olaf@aepfle.de, tim@xen.org, andres@gridcentric.ca, adin@gridcentric.ca
Subject: [PATCH 2 of 8] x86/mm: Fix p2m teardown locking
Date: Wed, 25 Jan 2012 22:53:26 -0500	[thread overview]
Message-ID: <2e7c77585adbb6aa3f04.1327550006@xdev.gridcentric.ca> (raw)
In-Reply-To: <patchbomb.1327550004@xdev.gridcentric.ca>

 xen/arch/x86/mm/p2m.c |  4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)


Holding the p2m lock during a p2m teardown, while unsharing entries pointing to
shared frames, causes a locking inversion and deadlock panic.

Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>

diff -r 143e4982c9bf -r 2e7c77585adb xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -343,8 +343,6 @@ void p2m_teardown(struct p2m_domain *p2m
     if (p2m == NULL)
         return;
 
-    p2m_lock(p2m);
-
 #ifdef __x86_64__
     for ( gfn=0; gfn < p2m->max_mapped_pfn; gfn++ )
     {
@@ -358,6 +356,8 @@ void p2m_teardown(struct p2m_domain *p2m
     }
 #endif
 
+    p2m_lock(p2m);
+
     p2m->phys_table = pagetable_null();
 
     while ( (pg = page_list_remove_head(&p2m->pages)) )

  parent reply	other threads:[~2012-01-26  3:53 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-26  3:53 [PATCH 0 of 8] x86/mm fixes Andres Lagar-Cavilla
2012-01-26  3:53 ` [PATCH 1 of 8] x86/mm: Fix paging_load Andres Lagar-Cavilla
2012-01-26  9:46   ` Olaf Hering
2012-01-26 10:49     ` Andres Lagar-Cavilla
2012-01-26 12:05       ` Olaf Hering
2012-01-26 12:23         ` Andres Lagar-Cavilla
2012-01-26 12:43           ` Olaf Hering
2012-01-26  3:53 ` Andres Lagar-Cavilla [this message]
2012-01-26  3:53 ` [PATCH 3 of 8] x86/mm: Allow foreign read-only mappings of shared pages Andres Lagar-Cavilla
2012-01-26  3:53 ` [PATCH 4 of 8] x86/mm: Output domain count of paged pages in console Andres Lagar-Cavilla
2012-01-26  9:47   ` Olaf Hering
2012-01-26  3:53 ` [PATCH 5 of 8] x86/mm: Remove stale variable from debugtrace printk in p2m audit Andres Lagar-Cavilla
2012-01-26  3:53 ` [PATCH 6 of 8] x86/mm: Properly account for paged out pages Andres Lagar-Cavilla
2012-01-26  9:54   ` Olaf Hering
2012-01-26 10:47     ` Andres Lagar-Cavilla
2012-01-26 12:11       ` Olaf Hering
2012-01-26 12:26         ` Andres Lagar-Cavilla
2012-01-26 13:08           ` Olaf Hering
2012-01-26  3:53 ` [PATCH 7 of 8] x86/mm: clean use of p2m unlocked queries Andres Lagar-Cavilla
2012-01-26  3:53 ` [PATCH 8 of 8] x86/mm: Avoid spurious deadlock panic trigger Andres Lagar-Cavilla
2012-01-26 13:31 ` [PATCH 0 of 8] x86/mm fixes Tim Deegan

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