From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:35440) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RJpmi-0001B1-2r for qemu-devel@nongnu.org; Fri, 28 Oct 2011 13:00:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RJpmh-0001R6-5d for qemu-devel@nongnu.org; Fri, 28 Oct 2011 13:00:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:30242) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RJpmg-0001R1-RV for qemu-devel@nongnu.org; Fri, 28 Oct 2011 12:59:59 -0400 Date: Fri, 28 Oct 2011 14:59:52 -0200 From: Luiz Capitulino Message-ID: <20111028145952.4bb63294@doriath> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] [PATCH v2] Fix segfault on migration completion List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel Cc: Paolo Bonzini , Eduardo Habkost , Juan Jose Quintela Carreira A simple migration reproduces it: 1. Start the source VM with: # qemu [...] -S 2. Start the destination VM with: # qemu -incoming tcp:0:4444 3. In the source VM: (qemu) migrate -d tcp:0:4444 4. The source VM will segfault as soon as migration completes (might not happen in the first try) What is happening here is that qemu_file_put_notify() can end up closing 's->file' (in which case it's also set to NULL). The call stack is rather complex, but Eduardo helped tracking it to: select loop -> migrate_fd_put_notify() -> qemu_file_put_notify() -> buffered_put_buffer() -> migrate_fd_put_ready() -> migrate_fd_completed() -> migrate_fd_cleanup(). To be honest, it's not completely clear to me in which cases 's->file' is not closed (on error maybe)? But I doubt this fix will make anything worse. Reviewed-by: Paolo Bonzini Acked-by: Eduardo Habkost Signed-off-by: Luiz Capitulino --- V2: better commit log migration.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/migration.c b/migration.c index bdca72e..f6e6208 100644 --- a/migration.c +++ b/migration.c @@ -252,7 +252,7 @@ static void migrate_fd_put_notify(void *opaque) qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL); qemu_file_put_notify(s->file); - if (qemu_file_get_error(s->file)) { + if (s->file && qemu_file_get_error(s->file)) { migrate_fd_error(s); } } -- 1.7.7.1.488.ge8e1c.dirty