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[Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full
From: |
Didier Pallard |
Subject: |
[Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full |
Date: |
Thu, 3 Dec 2015 10:53:17 +0100 |
unix_send_msgfds is used by vhost-user control socket. qemu_chr_fe_write_all
is used to send a message and retries as long as EAGAIN errno is set,
but write_msgfds buffer is freed after first EAGAIN failure, causing
message to be sent without proper fds attachment.
In case unix_send_msgfds is called through qemu_chr_fe_write, it will be
user responsability to resend message as is or to free write_msgfds
using set_msgfds(0)
Signed-off-by: Didier Pallard <address@hidden>
Reviewed-by: Thibaut Collet <address@hidden>
---
qemu-char.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/qemu-char.c b/qemu-char.c
index 5448b0f..26d5f2e 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2614,6 +2614,16 @@ static int unix_send_msgfds(CharDriverState *chr, const
uint8_t *buf, int len)
r = sendmsg(s->fd, &msgh, 0);
} while (r < 0 && errno == EINTR);
+ /* Ancillary data are not sent if no byte is written
+ * so don't free msgfds buffer if return value is EAGAIN
+ * If called from qemu_chr_fe_write_all retry will come soon
+ * If called from qemu_chr_fe_write, it is the user responsibility
+ * to resend message or free fds using set_msgfds(0)
+ */
+ if (r < 0 && errno == EAGAIN) {
+ return r;
+ }
+
/* free the written msgfds, no matter what */
if (s->write_msgfds_num) {
g_free(s->write_msgfds);
--
2.1.4
- [Qemu-devel] Linux vhost-user interrupt management fixes, Didier Pallard, 2015/12/03
- [Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full,
Didier Pallard <=
- Re: [Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full, Marc-André Lureau, 2015/12/07
- Re: [Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full, Victor Kaplansky, 2015/12/09
- Re: [Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full, Didier Pallard, 2015/12/09
- Re: [Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full, Victor Kaplansky, 2015/12/10
- Re: [Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full, Didier Pallard, 2015/12/10
- Re: [Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full, Victor Kaplansky, 2015/12/17
[Qemu-devel] [PATCH 2/3] virtio-pci: add an option to bypass guest_notifier_mask, Didier Pallard, 2015/12/03