{"id":2225495,"url":"http://patchwork.ozlabs.org/api/patches/2225495/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260421052227.8278-1-prtyagi@redhat.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260421052227.8278-1-prtyagi@redhat.com>","list_archive_url":null,"date":"2026-04-21T05:22:27","name":"migration: Fix blocking in POSTCOPY_DEVICE during package load","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"8f912c7f04e7f7c698f290c90fb1ee59fc1c5701","submitter":{"id":93199,"url":"http://patchwork.ozlabs.org/api/people/93199/?format=json","name":"Pranav Tyagi","email":"prtyagi@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260421052227.8278-1-prtyagi@redhat.com/mbox/","series":[{"id":500732,"url":"http://patchwork.ozlabs.org/api/series/500732/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=500732","date":"2026-04-21T05:22:27","name":"migration: Fix blocking in POSTCOPY_DEVICE during package load","version":1,"mbox":"http://patchwork.ozlabs.org/series/500732/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2225495/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2225495/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=Gj1o1qO/;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=google header.b=IXgiEvht;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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envelope-from=prtyagi@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_PASS=-0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"The package_loaded event is not set in case MIG_RP_MSG_PONG does not\narrive on the source from the destination in the return path thread. The\nmigration thread would then be blocked waiting for package_loaded event\nindefinitely in POSTCOPY_DEVICE state. Where as, in such a condition the\nsource VM can safely resume as the destination has not yet started. The\npong message can get lost in case of a network failure or destination\ncrash before sending the pong.\n\nThis patch uses the error detected in case of network failure or\ndestination crash to set the package_loaded event in the out path of the\nreturn path thread. This will kick the migration thread out from\na condition of indefinitely waiting for the package_loaded event. The\nmigration thread then fails early and breaks from the migration loop to\nresume the VM on the source side.\n\nFixes: 7b842fe354c6 (\"migration: Introduce POSTCOPY_DEVICE state\")\nSigned-off-by: Pranav Tyagi \n---\n migration/migration.c | 20 ++++++++++++++++++++\n 1 file changed, 20 insertions(+)","diff":"diff --git a/migration/migration.c b/migration/migration.c\nindex 5c9aaa6e58..1656c1203c 100644\n--- a/migration/migration.c\n+++ b/migration/migration.c\n@@ -2386,6 +2386,15 @@ out:\n if (err) {\n migrate_error_propagate(ms, err);\n trace_source_return_path_thread_bad_end();\n+ if (ms->state == MIGRATION_STATUS_POSTCOPY_DEVICE) {\n+ /*\n+ * Kick the migration thread if it gets stuck in\n+ * POSTCOPY_DEVICE state waiting for\n+ * postcopy_package_loaded_event. The event will never be\n+ * set as MIG_RP_MSG_PONG from the destination is lost.\n+ */\n+ qemu_event_set(&ms->postcopy_package_loaded_event);\n+ }\n }\n \n if (ms->state == MIGRATION_STATUS_POSTCOPY_RECOVER) {\n@@ -3232,6 +3241,17 @@ static MigIterateState migration_iteration_run(MigrationState *s)\n * package before actually completing.\n */\n qemu_event_wait(&s->postcopy_package_loaded_event);\n+ /*\n+ * Check for errors in case the migration thread was stuck in\n+ * POSTCOPY_DEVICE state waiting for the\n+ * postcopy_package_loaded_event which was never set.\n+ * If so, fail now and break out of the iteration.\n+ */\n+ if (migrate_has_error(s)) {\n+ migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_DEVICE,\n+ MIGRATION_STATUS_FAILING);\n+ return MIG_ITERATE_BREAK;\n+ }\n migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_DEVICE,\n MIGRATION_STATUS_POSTCOPY_ACTIVE);\n }\n","prefixes":[]}