Re: [PATCH v2 1/5] char-socket: return -1 in case of disconnect during tcp_chr_write

2020-05-06 Thread Marc-André Lureau 
On Thu, Apr 30, 2020 at 3:37 PM Dima Stepanov  wrote:
>
> During testing of the vhost-user-blk reconnect functionality the qemu
> SIGSEGV was triggered:
>  start qemu as:
>  x86_64-softmmu/qemu-system-x86_64 -m 1024M -M q35 \
>-object 
> memory-backend-file,id=ram-node0,size=1024M,mem-path=/dev/shm/qemu,share=on \
>-numa node,cpus=0,memdev=ram-node0 \
>-chardev socket,id=chardev0,path=./vhost.sock,noserver,reconnect=1 \
>-device vhost-user-blk-pci,chardev=chardev0,num-queues=4 --enable-kvm
>  start vhost-user-blk daemon:
>  ./vhost-user-blk -s ./vhost.sock -b test-img.raw
>
> If vhost-user-blk will be killed during the vhost initialization
> process, for instance after getting VHOST_SET_VRING_CALL command, then
> QEMU will fail with the following backtrace:
>
> Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
> 0x559272bb in vhost_user_read (dev=0x7fffef2d53e0, msg=0x7fffd5b0)
> at ./hw/virtio/vhost-user.c:260
> 260 CharBackend *chr = u->user->chr;
>
>  #0  0x559272bb in vhost_user_read (dev=0x7fffef2d53e0, 
> msg=0x7fffd5b0)
> at ./hw/virtio/vhost-user.c:260
>  #1  0x5592acb8 in vhost_user_get_config (dev=0x7fffef2d53e0, 
> config=0x7fffef2d5394 "", config_len=60)
> at ./hw/virtio/vhost-user.c:1645
>  #2  0x55925525 in vhost_dev_get_config (hdev=0x7fffef2d53e0, 
> config=0x7fffef2d5394 "", config_len=60)
> at ./hw/virtio/vhost.c:1490
>  #3  0x558cc46b in vhost_user_blk_device_realize (dev=0x7fffef2d51a0, 
> errp=0x7fffd8f0)
> at ./hw/block/vhost-user-blk.c:429
>  #4  0x55920090 in virtio_device_realize (dev=0x7fffef2d51a0, 
> errp=0x7fffd948)
> at ./hw/virtio/virtio.c:3615
>  #5  0x55a9779c in device_set_realized (obj=0x7fffef2d51a0, 
> value=true, errp=0x7fffdb88)
> at ./hw/core/qdev.c:891
>  ...
>
> The problem is that vhost_user_write doesn't get an error after
> disconnect and try to call vhost_user_read(). The tcp_chr_write()
> routine should return -1 in case of disconnect. Indicate the EIO error
> if this routine is called in the disconnected state.
>
> Signed-off-by: Dima Stepanov 


Reviewed-by: Marc-André Lureau 

> ---
>  chardev/char-socket.c | 8 +---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/chardev/char-socket.c b/chardev/char-socket.c
> index 185fe38..c128cca 100644
> --- a/chardev/char-socket.c
> +++ b/chardev/char-socket.c
> @@ -175,14 +175,16 @@ static int tcp_chr_write(Chardev *chr, const uint8_t 
> *buf, int len)
>  if (ret < 0 && errno != EAGAIN) {
>  if (tcp_chr_read_poll(chr) <= 0) {
>  tcp_chr_disconnect_locked(chr);
> -return len;
> +/* Return an error since we made a disconnect. */
> +return ret;
>  } /* else let the read handler finish it properly */
>  }
>
>  return ret;
>  } else {
> -/* XXX: indicate an error ? */
> -return len;
> +/* Indicate an error. */
> +errno = EIO;
> +return -1;
>  }
>  }
>
> --
> 2.7.4
>

Re: [PATCH v2 1/5] char-socket: return -1 in case of disconnect during tcp_chr_write

2020-05-06 Thread Li Feng 
Thanks,

Feng Li

Dima Stepanov  于2020年4月30日周四 下午9:36写道：
>
> During testing of the vhost-user-blk reconnect functionality the qemu
> SIGSEGV was triggered:
>  start qemu as:
>  x86_64-softmmu/qemu-system-x86_64 -m 1024M -M q35 \
>-object 
> memory-backend-file,id=ram-node0,size=1024M,mem-path=/dev/shm/qemu,share=on \
>-numa node,cpus=0,memdev=ram-node0 \
>-chardev socket,id=chardev0,path=./vhost.sock,noserver,reconnect=1 \
>-device vhost-user-blk-pci,chardev=chardev0,num-queues=4 --enable-kvm
>  start vhost-user-blk daemon:
>  ./vhost-user-blk -s ./vhost.sock -b test-img.raw
>
> If vhost-user-blk will be killed during the vhost initialization
> process, for instance after getting VHOST_SET_VRING_CALL command, then
> QEMU will fail with the following backtrace:
>
> Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
> 0x559272bb in vhost_user_read (dev=0x7fffef2d53e0, msg=0x7fffd5b0)
> at ./hw/virtio/vhost-user.c:260
> 260 CharBackend *chr = u->user->chr;
>
>  #0  0x559272bb in vhost_user_read (dev=0x7fffef2d53e0, 
> msg=0x7fffd5b0)
> at ./hw/virtio/vhost-user.c:260
>  #1  0x5592acb8 in vhost_user_get_config (dev=0x7fffef2d53e0, 
> config=0x7fffef2d5394 "", config_len=60)
> at ./hw/virtio/vhost-user.c:1645
>  #2  0x55925525 in vhost_dev_get_config (hdev=0x7fffef2d53e0, 
> config=0x7fffef2d5394 "", config_len=60)
> at ./hw/virtio/vhost.c:1490
>  #3  0x558cc46b in vhost_user_blk_device_realize (dev=0x7fffef2d51a0, 
> errp=0x7fffd8f0)
> at ./hw/block/vhost-user-blk.c:429
>  #4  0x55920090 in virtio_device_realize (dev=0x7fffef2d51a0, 
> errp=0x7fffd948)
> at ./hw/virtio/virtio.c:3615
>  #5  0x55a9779c in device_set_realized (obj=0x7fffef2d51a0, 
> value=true, errp=0x7fffdb88)
> at ./hw/core/qdev.c:891
>  ...
>
> The problem is that vhost_user_write doesn't get an error after
> disconnect and try to call vhost_user_read(). The tcp_chr_write()
> routine should return -1 in case of disconnect. Indicate the EIO error
> if this routine is called in the disconnected state.
>
> Signed-off-by: Dima Stepanov 
> ---
>  chardev/char-socket.c | 8 +---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/chardev/char-socket.c b/chardev/char-socket.c
> index 185fe38..c128cca 100644
> --- a/chardev/char-socket.c
> +++ b/chardev/char-socket.c
> @@ -175,14 +175,16 @@ static int tcp_chr_write(Chardev *chr, const uint8_t 
> *buf, int len)
>  if (ret < 0 && errno != EAGAIN) {
>  if (tcp_chr_read_poll(chr) <= 0) {
>  tcp_chr_disconnect_locked(chr);
> -return len;
> +/* Return an error since we made a disconnect. */
> +return ret;
The `return` statement could be deleted.
The outside has a return statement.

>  } /* else let the read handler finish it properly */
>  }
>
>  return ret;
>  } else {
> -/* XXX: indicate an error ? */
> -return len;
> +/* Indicate an error. */
> +errno = EIO;
> +return -1;
>  }
>  }
>
> --
> 2.7.4
>

[PATCH v2 1/5] char-socket: return -1 in case of disconnect during tcp_chr_write

2020-04-30 Thread Dima Stepanov 
During testing of the vhost-user-blk reconnect functionality the qemu
SIGSEGV was triggered:
 start qemu as:
 x86_64-softmmu/qemu-system-x86_64 -m 1024M -M q35 \
   -object 
memory-backend-file,id=ram-node0,size=1024M,mem-path=/dev/shm/qemu,share=on \
   -numa node,cpus=0,memdev=ram-node0 \
   -chardev socket,id=chardev0,path=./vhost.sock,noserver,reconnect=1 \
   -device vhost-user-blk-pci,chardev=chardev0,num-queues=4 --enable-kvm
 start vhost-user-blk daemon:
 ./vhost-user-blk -s ./vhost.sock -b test-img.raw

If vhost-user-blk will be killed during the vhost initialization
process, for instance after getting VHOST_SET_VRING_CALL command, then
QEMU will fail with the following backtrace:

Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
0x559272bb in vhost_user_read (dev=0x7fffef2d53e0, msg=0x7fffd5b0)
at ./hw/virtio/vhost-user.c:260
260 CharBackend *chr = u->user->chr;

 #0  0x559272bb in vhost_user_read (dev=0x7fffef2d53e0, 
msg=0x7fffd5b0)
at ./hw/virtio/vhost-user.c:260
 #1  0x5592acb8 in vhost_user_get_config (dev=0x7fffef2d53e0, 
config=0x7fffef2d5394 "", config_len=60)
at ./hw/virtio/vhost-user.c:1645
 #2  0x55925525 in vhost_dev_get_config (hdev=0x7fffef2d53e0, 
config=0x7fffef2d5394 "", config_len=60)
at ./hw/virtio/vhost.c:1490
 #3  0x558cc46b in vhost_user_blk_device_realize (dev=0x7fffef2d51a0, 
errp=0x7fffd8f0)
at ./hw/block/vhost-user-blk.c:429
 #4  0x55920090 in virtio_device_realize (dev=0x7fffef2d51a0, 
errp=0x7fffd948)
at ./hw/virtio/virtio.c:3615
 #5  0x55a9779c in device_set_realized (obj=0x7fffef2d51a0, value=true, 
errp=0x7fffdb88)
at ./hw/core/qdev.c:891
 ...

The problem is that vhost_user_write doesn't get an error after
disconnect and try to call vhost_user_read(). The tcp_chr_write()
routine should return -1 in case of disconnect. Indicate the EIO error
if this routine is called in the disconnected state.

Signed-off-by: Dima Stepanov 
---
 chardev/char-socket.c | 8 +---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index 185fe38..c128cca 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -175,14 +175,16 @@ static int tcp_chr_write(Chardev *chr, const uint8_t 
*buf, int len)
 if (ret < 0 && errno != EAGAIN) {
 if (tcp_chr_read_poll(chr) <= 0) {
 tcp_chr_disconnect_locked(chr);
-return len;
+/* Return an error since we made a disconnect. */
+return ret;
 } /* else let the read handler finish it properly */
 }
 
 return ret;
 } else {
-/* XXX: indicate an error ? */
-return len;
+/* Indicate an error. */
+errno = EIO;
+return -1;
 }
 }
 
-- 
2.7.4