[CRIU] Using p.haul migration failure

[Pavel Emelyanov]

On 10/28/2014 06:07 AM, Sowmini Varadhan wrote:
> On (10/27/14 17:21), Pavel Emelyanov wrote:
>>
>> Pre-dump logs terminate at collect_mntinfo() and the criu just quits.
>> This typically happens when it crashes somewhere afterwards, so it
>> would be useful if you could help us fining out where.
>>
> 
> It's seg-faulting here:
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x000000000046624d in validate_mounts (info=0x114e050, for_dump=true)
>     at mount.c:433
> 433                                             ret = run_plugins(DUMP_EXT_MOUNT, m->mountpoint, m->mnt_id);

Ah, I see. This is a pre-dump during which plugins are not initialized,
but mount.c tries to call them on unsupported (external?) mountpoint.

> Is there something wrong with these values? How to tell? How to validate
> this data?

No, the problem is in plugins are called for unsupported mount points,
while not initialized. Can you check this patch:

diff --git a/include/namespaces.h b/include/namespaces.h
index 9b93b29..79327f5 100644
--- a/include/namespaces.h
+++ b/include/namespaces.h
@@ -48,7 +48,7 @@ extern struct collect_image_info nsfile_cinfo;
 
 extern int walk_namespaces(struct ns_desc *nd, int (*cb)(struct ns_id *, void *), void *oarg);
 extern int collect_namespaces(bool for_dump);
-extern int collect_mnt_namespaces(void);
+extern int collect_mnt_namespaces(bool for_dump);
 extern int dump_mnt_namespaces(void);
 extern int dump_namespaces(struct pstree_item *item, unsigned int ns_flags);
 extern int prepare_namespace(struct pstree_item *item, unsigned long clone_flags);
diff --git a/mount.c b/mount.c
index a60c86e..59ffe53 100644
--- a/mount.c
+++ b/mount.c
@@ -2097,7 +2097,7 @@ static int collect_mntns(struct ns_id *ns, void *oarg)
 	return 0;
 }
 
-int collect_mnt_namespaces(void)
+int collect_mnt_namespaces(bool for_dump)
 {
 	int need_to_validate = 0, ret;
 
@@ -2105,7 +2105,7 @@ int collect_mnt_namespaces(void)
 	if (ret)
 		goto err;
 
-	if (need_to_validate) {
+	if (for_dump && need_to_validate) {
 		if (collect_shared(mntinfo))
 			goto err;
 		if (validate_mounts(mntinfo, true))
diff --git a/namespaces.c b/namespaces.c
index 87849fa..481b23d 100644
--- a/namespaces.c
+++ b/namespaces.c
@@ -574,7 +574,7 @@ int collect_namespaces(bool for_dump)
 {
 	int ret;
 
-	ret = collect_mnt_namespaces();
+	ret = collect_mnt_namespaces(for_dump);
 	if (ret < 0)
 		return ret;
 

---

Please, note, that your dump stage will fail anyway, as there are some
mount points in your program, that CRIU doesn't support for now. Let's
check what it is.

Thanks,
Pavel