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From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
To: qemu-block@nongnu.org
Cc: "Kevin Wolf" <kwolf@redhat.com>, "Fam Zheng" <fam@euphon.net>,
	"Vladimir Sementsov-Ogievskiy" <vsementsov@virtuozzo.com>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Juan Quintela" <quintela@redhat.com>,
	"John Snow" <jsnow@redhat.com>,
	"Emanuele Giuseppe Esposito" <eesposit@redhat.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	qemu-devel@nongnu.org, "Hanna Reitz" <hreitz@redhat.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Eric Blake" <eblake@redhat.com>
Subject: [RFC PATCH 2/4] migration: block-dirty-bitmap: add missing qemu_mutex_lock_iothread
Date: Wed,  8 Sep 2021 09:10:19 -0400	[thread overview]
Message-ID: <20210908131021.774533-3-eesposit@redhat.com> (raw)
In-Reply-To: <20210908131021.774533-1-eesposit@redhat.com>

init_dirty_bitmap_migration assumes the iothread lock (BQL)
to be held, but instead it isn't.

Instead of adding the lock to qemu_savevm_state_setup(),
follow the same pattern as the other ->save_setup callbacks
and lock+unlock inside dirty_bitmap_save_setup().

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 migration/block-dirty-bitmap.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
index 35f5ef688d..9aba7d9c22 100644
--- a/migration/block-dirty-bitmap.c
+++ b/migration/block-dirty-bitmap.c
@@ -1215,7 +1215,10 @@ static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque)
 {
     DBMSaveState *s = &((DBMState *)opaque)->save;
     SaveBitmapState *dbms = NULL;
+
+    qemu_mutex_lock_iothread();
     if (init_dirty_bitmap_migration(s) < 0) {
+        qemu_mutex_unlock_iothread();
         return -1;
     }
 
@@ -1223,7 +1226,7 @@ static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque)
         send_bitmap_start(f, s, dbms);
     }
     qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);
-
+    qemu_mutex_unlock_iothread();
     return 0;
 }
 
-- 
2.27.0



  parent reply	other threads:[~2021-09-08 13:12 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-08 13:10 [RFC PATCH 0/4] block layer: split block APIs in graph and I/O Emanuele Giuseppe Esposito
2021-09-08 13:10 ` [RFC PATCH 1/4] main-loop.h: introduce qemu_in_main_thread() Emanuele Giuseppe Esposito
2021-09-13 13:15   ` Stefan Hajnoczi
2021-09-08 13:10 ` Emanuele Giuseppe Esposito [this message]
2021-09-13 13:19   ` [RFC PATCH 2/4] migration: block-dirty-bitmap: add missing qemu_mutex_lock_iothread Stefan Hajnoczi
2021-09-08 13:10 ` [RFC PATCH 3/4] include/sysemu/block-backend: split header into I/O and graph API Emanuele Giuseppe Esposito
2021-09-13 13:27   ` Stefan Hajnoczi
2021-09-15 12:14     ` Paolo Bonzini
2021-09-15 14:38       ` Stefan Hajnoczi
2021-09-13 13:41   ` Stefan Hajnoczi
2021-09-08 13:10 ` [RFC PATCH 4/4] block/block-backend.c: assertions for block-backend Emanuele Giuseppe Esposito
2021-09-13 13:38   ` Stefan Hajnoczi
2021-09-13 13:10 ` [RFC PATCH 0/4] block layer: split block APIs in graph and I/O Stefan Hajnoczi
2021-09-15 12:11   ` Paolo Bonzini
2021-09-15 14:43     ` Stefan Hajnoczi
2021-09-16 14:03       ` Emanuele Giuseppe Esposito
2021-09-16 19:49         ` Paolo Bonzini
2021-09-13 13:39 ` Stefan Hajnoczi

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