Migration 20240423 patches

[PULL 26/26] migration/colo: Fix bdrv_graph_rdlock_main_loop: Assertion `!qemu_in_coroutine()' failed.

Peter Xu posted 26 patches 1 year, 9 months ago

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Maintainers: Stefano Stabellini <sstabellini@kernel.org>, Anthony Perard <anthony.perard@citrix.com>, Paul Durrant <paul@xen.org>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, Nicholas Piggin <npiggin@gmail.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, David Gibson <david@gibson.dropbear.id.au>, Harsh Prateek Bora <harshpb@linux.ibm.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, David Hildenbrand <david@redhat.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Thomas Huth <thuth@redhat.com>, Alex Williamson <alex.williamson@redhat.com>, "Cédric Le Goater" <clg@redhat.com>, Peter Xu <peterx@redhat.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Fabiano Rosas <farosas@suse.de>, Stefan Hajnoczi <stefanha@redhat.com>, Fam Zheng <fam@euphon.net>, Eric Blake <eblake@redhat.com>, Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>, John Snow <jsnow@redhat.com>, Hailiang Zhang <zhanghailiang@xfusion.com>, Hyman Huang <yong.huang@smartx.com>, Laurent Vivier <lvivier@redhat.com>

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[PULL 26/26] migration/colo: Fix bdrv_graph_rdlock_main_loop: Assertion `!qemu_in_coroutine()' failed.

Posted by Peter Xu 1 year, 9 months ago

From: Li Zhijian <lizhijian@fujitsu.com>

bdrv_activate_all() should not be called from the coroutine context, move
it to the QEMU thread colo_process_incoming_thread() with the bql_lock
protected.

The backtrace is as follows:
 #4  0x0000561af7948362 in bdrv_graph_rdlock_main_loop () at ../block/graph-lock.c:260
 #5  0x0000561af7907a68 in graph_lockable_auto_lock_mainloop (x=0x7fd29810be7b) at /patch/to/qemu/include/block/graph-lock.h:259
 #6  0x0000561af79167d1 in bdrv_activate_all (errp=0x7fd29810bed0) at ../block.c:6906
 #7  0x0000561af762b4af in colo_incoming_co () at ../migration/colo.c:935
 #8  0x0000561af7607e57 in process_incoming_migration_co (opaque=0x0) at ../migration/migration.c:793
 #9  0x0000561af7adbeeb in coroutine_trampoline (i0=-106876144, i1=22042) at ../util/coroutine-ucontext.c:175
 #10 0x00007fd2a5cf21c0 in  () at /lib64/libc.so.6

Cc: qemu-stable@nongnu.org
Cc: Fabiano Rosas <farosas@suse.de>
Closes: https://gitlab.com/qemu-project/qemu/-/issues/2277
Fixes: 2b3912f135 ("block: Mark bdrv_first_blk() and bdrv_is_root_node() GRAPH_RDLOCK")
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Tested-by: Zhang Chen <chen.zhang@intel.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240417025634.1014582-1-lizhijian@fujitsu.com
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/colo.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/migration/colo.c b/migration/colo.c
index 84632a603e..5600a43d78 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -835,6 +835,16 @@ static void *colo_process_incoming_thread(void *opaque)
         return NULL;
     }
 
+    /* Make sure all file formats throw away their mutable metadata */
+    bql_lock();
+    bdrv_activate_all(&local_err);
+    if (local_err) {
+        bql_unlock();
+        error_report_err(local_err);
+        return NULL;
+    }
+    bql_unlock();
+
     failover_init_state();
 
     mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);
@@ -922,7 +932,6 @@ out:
 int coroutine_fn colo_incoming_co(void)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
-    Error *local_err = NULL;
     QemuThread th;
 
     assert(bql_locked());
@@ -931,13 +940,6 @@ int coroutine_fn colo_incoming_co(void)
         return 0;
     }
 
-    /* Make sure all file formats throw away their mutable metadata */
-    bdrv_activate_all(&local_err);
-    if (local_err) {
-        error_report_err(local_err);
-        return -EINVAL;
-    }
-
     qemu_thread_create(&th, "COLO incoming", colo_process_incoming_thread,
                        mis, QEMU_THREAD_JOINABLE);
 
-- 
2.44.0