[PATCH v2-hci-8.0 2/2] migration/cpr: lock the ramblocks #VSTOR-145529

["Denis V. Lunev" <den@openvz.org>]

From: Denis V. Lunev <den@openvz.org>

The ramblock entries live in the same registry as the descriptors and
are reached the same way, from RAM block setup and teardown, so they
need the same protection.

Take the lock in their accessors too. qemu_ram_free() already holds the
ramlist mutex when it calls in here, and nothing takes the two in the
other order.

Signed-off-by: Denis V. Lunev <den@openvz.org>
---
 migration/cpr.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/migration/cpr.c b/migration/cpr.c
index e2a76c96a2b..a149e790c10 100644
--- a/migration/cpr.c
+++ b/migration/cpr.c
@@ -239,8 +239,13 @@ static CprRamBlock *find_ramblock(CprRamBlockList *head, const char *name)
 
 void cpr_save_ramblock(const char *name, cpr_ramblock_t ram)
 {
-    CprRamBlock *elem = find_ramblock(&cpr_state.ramblocks, name);
-    cpr_ramblock_t old_ram = elem ? elem->ram : (cpr_ramblock_t) {0, 0};
+    CprRamBlock *elem;
+    cpr_ramblock_t old_ram;
+
+    QEMU_LOCK_GUARD(&cpr_state_lock);
+
+    elem = find_ramblock(&cpr_state.ramblocks, name);
+    old_ram = elem ? elem->ram : (cpr_ramblock_t) {0, 0};
 
     if (old_ram.addr == 0) {
         do_cpr_save_ramblock(name, ram);
@@ -255,7 +260,11 @@ void cpr_save_ramblock(const char *name, cpr_ramblock_t ram)
 
 void cpr_delete_ramblock(const char *name)
 {
-    CprRamBlock *elem = find_ramblock(&cpr_state.ramblocks, name);
+    CprRamBlock *elem;
+
+    QEMU_LOCK_GUARD(&cpr_state_lock);
+
+    elem = find_ramblock(&cpr_state.ramblocks, name);
 
     if (elem) {
         QLIST_REMOVE(elem, next);
@@ -268,8 +277,13 @@ void cpr_delete_ramblock(const char *name)
 
 cpr_ramblock_t cpr_find_ramblock(const char *name)
 {
-    CprRamBlock *elem = find_ramblock(&cpr_state.ramblocks, name);
-    cpr_ramblock_t ram = elem ? elem->ram : (cpr_ramblock_t) {0, 0};
+    CprRamBlock *elem;
+    cpr_ramblock_t ram;
+
+    QEMU_LOCK_GUARD(&cpr_state_lock);
+
+    elem = find_ramblock(&cpr_state.ramblocks, name);
+    ram = elem ? elem->ram : (cpr_ramblock_t) {0, 0};
 
     trace_cpr_find_ramblock(name, (void *) ram.addr, ram.length);
     return ram;
@@ -279,6 +293,8 @@ bool cpr_walk_ramblock(cpr_walk_ramblock_cb cb)
 {
     CprRamBlock *elem;
 
+    QEMU_LOCK_GUARD(&cpr_state_lock);
+
     QLIST_FOREACH(elem, &cpr_state.ramblocks, next) {
         g_assert(elem->ram.addr && elem->ram.length);
         if (!cb(elem->ram, elem->name)) {
-- 
2.53.0