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hw/vfio-user: wait for proxy close correctly

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Coverity reported:

CID 1611806: Concurrent data access violations (BAD_CHECK_OF_WAIT_COND)

A wait is performed without a loop. If there is a spurious wakeup, the
condition may not be satisfied.

Fix this by checking ->state for VFIO_PROXY_CLOSED in a loop.

Also rename the callback for clarity.

Signed-off-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Mark Cave-Ayland <markcaveayland@nutanix.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250715115954.515819-4-john.levon@nutanix.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
John Levon 2025-07-15 13:59:53 +02:00 • committed by Cédric Le Goater
parent 09353802f0
commit ea6788440d
1 changed files with 6 additions and 4 deletions
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10
hw/vfio-user/proxy.c
View file

@ -32,7 +32,6 @@ static void vfio_user_recycle(VFIOUserProxy *proxy, VFIOUserMsg *msg);
static void vfio_user_recv(void *opaque);
static void vfio_user_send(void *opaque);
static void vfio_user_cb(void *opaque);
static void vfio_user_request(void *opaque);
@ -492,7 +491,7 @@ static void vfio_user_send(void *opaque)
}
}
static void vfio_user_cb(void *opaque)
static void vfio_user_close_cb(void *opaque)
{
VFIOUserProxy *proxy = opaque;
@ -984,8 +983,11 @@ void vfio_user_disconnect(VFIOUserProxy *proxy)
* handler to run after the proxy fd handlers were
* deleted above.
*/
aio_bh_schedule_oneshot(proxy->ctx, vfio_user_cb, proxy);
qemu_cond_wait(&proxy->close_cv, &proxy->lock);
aio_bh_schedule_oneshot(proxy->ctx, vfio_user_close_cb, proxy);
while (proxy->state != VFIO_PROXY_CLOSED) {
qemu_cond_wait(&proxy->close_cv, &proxy->lock);
}
/* we now hold the only ref to proxy */
qemu_mutex_unlock(&proxy->lock);