[Xen-devel] [PATCH 2/8] xen: add using domlist_read_lock in keyhandlers

From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: "Juergen Gross" <jgross@suse.com>,
	"Kevin Tian" <kevin.tian@intel.com>,
	"Stefano Stabellini" <sstabellini@kernel.org>,
	"Julien Grall" <julien@xen.org>,
	"Jun Nakajima" <jun.nakajima@intel.com>, "Wei Liu" <wl@xen.org>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"George Dunlap" <george.dunlap@eu.citrix.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Ian Jackson" <ian.jackson@eu.citrix.com>,
	"Jan Beulich" <jbeulich@suse.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: [Xen-devel] [PATCH 2/8] xen: add using domlist_read_lock in keyhandlers
Date: Thu, 13 Feb 2020 13:54:43 +0100	[thread overview]
Message-ID: <20200213125449.14226-3-jgross@suse.com> (raw)
In-Reply-To: <20200213125449.14226-1-jgross@suse.com>

Using for_each_domain() with out holding the domlist_read_lock is
fragile, so add the lock in the keyhandlers it is missing.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 xen/arch/x86/mm/p2m-ept.c       | 4 ++++
 xen/arch/x86/time.c             | 5 +++++
 xen/common/grant_table.c        | 7 +++++++
 xen/drivers/passthrough/iommu.c | 5 +++++
 4 files changed, 21 insertions(+)

diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index d4defa01c2..eb0f0edfef 100644
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -1297,6 +1297,8 @@ static void ept_dump_p2m_table(unsigned char key)
     struct p2m_domain *p2m;
     struct ept_data *ept;
 
+    rcu_read_lock(&domlist_read_lock);
+
     for_each_domain(d)
     {
         if ( !hap_enabled(d) )
@@ -1347,6 +1349,8 @@ static void ept_dump_p2m_table(unsigned char key)
             unmap_domain_page(table);
         }
     }
+
+    rcu_read_unlock(&domlist_read_lock);
 }
 
 void setup_ept_dump(void)
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index cf3e51fb5e..509679235d 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -2401,6 +2401,9 @@ static void dump_softtsc(unsigned char key)
     } else
         printk("TSC not marked as either constant or reliable, "
                "warp=%lu (count=%lu)\n", tsc_max_warp, tsc_check_count);
+
+    rcu_read_lock(&domlist_read_lock);
+
     for_each_domain ( d )
     {
         if ( is_hardware_domain(d) && d->arch.tsc_mode == TSC_MODE_DEFAULT )
@@ -2417,6 +2420,8 @@ static void dump_softtsc(unsigned char key)
         domcnt++;
     }
 
+    rcu_read_unlock(&domlist_read_lock);
+
     if ( !domcnt )
             printk("No domains have emulated TSC\n");
 }
diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index 2ecf38dfbe..c793927cd6 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -4104,9 +4104,16 @@ static void gnttab_usage_print(struct domain *rd)
 static void gnttab_usage_print_all(unsigned char key)
 {
     struct domain *d;
+
     printk("%s [ key '%c' pressed\n", __func__, key);
+
+    rcu_read_lock(&domlist_read_lock);
+
     for_each_domain ( d )
         gnttab_usage_print(d);
+
+    rcu_read_unlock(&domlist_read_lock);
+
     printk("%s ] done\n", __func__);
 }
 
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 9d421e06de..cab7a068aa 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -591,6 +591,9 @@ static void iommu_dump_p2m_table(unsigned char key)
     }
 
     ops = iommu_get_ops();
+
+    rcu_read_lock(&domlist_read_lock);
+
     for_each_domain(d)
     {
         if ( is_hardware_domain(d) || !is_iommu_enabled(d) )
@@ -605,6 +608,8 @@ static void iommu_dump_p2m_table(unsigned char key)
         printk("\ndomain%d IOMMU p2m table: \n", d->domain_id);
         ops->dump_p2m_table(d);
     }
+
+    rcu_read_unlock(&domlist_read_lock);
 }
 
 /*
-- 
2.16.4


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