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From: Fabiano Rosas <farosas@suse.de>
To: qemu-devel@nongnu.org
Cc: "Juan Quintela" <quintela@redhat.com>,
	"Peter Xu" <peterx@redhat.com>,
	"Leonardo Bras" <leobras@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>
Subject: [RFC PATCH 0/2] migration: Fix multifd qemu_mutex_destroy race
Date: Thu,  9 Nov 2023 13:58:54 -0300	[thread overview]
Message-ID: <20231109165856.15224-1-farosas@suse.de> (raw)

We're calling qemu_sem_post() in threads other than the multifd
channel and the migration thread. This is vulnerable to a race with
multifd_save_cleanup() which calls qemu_sem_destroy(). If we attempt
to destroy the semaphore mutex with the lock taken, the code asserts.

We're hitting this in the current master and we've had reports of this
in the past already:

[PATCH] migrate/multifd: fix coredump when the multifd thread cleanup
https://lore.kernel.org/r/20230621081826.3203053-1-zhangjianguo18@huawei.com

Fabiano Rosas (2):
  migration: Report error in incoming migration
  migration/multifd: Move semaphore release into main thread

 migration/migration.c | 11 ++++++++++-
 migration/multifd.c   | 29 +++++++++++------------------
 2 files changed, 21 insertions(+), 19 deletions(-)

-- 
2.35.3



             reply	other threads:[~2023-11-09 16:59 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-09 16:58 Fabiano Rosas [this message]
2023-11-09 16:58 ` [RFC PATCH 1/2] migration: Report error in incoming migration Fabiano Rosas
2023-11-09 18:57   ` Peter Xu
2023-11-10 10:58     ` Fabiano Rosas
2023-11-13 16:51       ` Peter Xu
2023-11-14  1:54         ` Fabiano Rosas
2023-11-09 16:58 ` [RFC PATCH 2/2] migration/multifd: Move semaphore release into main thread Fabiano Rosas
2023-11-09 18:56   ` Peter Xu
2023-11-10 12:05     ` Fabiano Rosas
2023-11-10 12:37       ` Fabiano Rosas
2023-11-16 15:51         ` Juan Quintela
2023-11-13 16:45       ` Peter Xu
2023-11-14  1:50         ` Fabiano Rosas
2023-11-14 17:28           ` Peter Xu
2023-11-16 15:44       ` Juan Quintela
2023-11-16 14:56     ` Juan Quintela
2023-11-16 18:13       ` Fabiano Rosas

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