[dpdk-dev] [PATCH 1/3] vhost: fix error path when setting memory tables

Xia, Chenbo chenbo.xia at intel.com
Fri Nov 6 03:53:00 CET 2020


Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin at redhat.com>
> Sent: Thursday, November 5, 2020 7:46 PM
> To: dev at dpdk.org; Ding, Xuan <xuan.ding at intel.com>;
> stephen at networkplumber.org; Yigit, Ferruh <ferruh.yigit at intel.com>;
> thomas at monjalon.net; Xia, Chenbo <chenbo.xia at intel.com>
> Cc: stable at dpdk.org; Maxime Coquelin <maxime.coquelin at redhat.com>
> Subject: [PATCH 1/3] vhost: fix error path when setting memory tables
> 
> If the an error is encountered before the memory regions

'the' should be deleted.

> are parsed, the file descriptors for these shared buffers
> is leaked.

s/is/are/

> 
> This patch fixes this by closing the message file descriptors
> on error, taking care of avoiding double closing of the file
> descriptors. guest_pages is also freed, even though it was not
> leaked as its pointer was not overiden on subsequent function

s/overiden/overridden

With above changes:

Reviewed-by: Chenbo Xia <chenbo.xia at intel.com>

> calls.
> 
> Fixes: 8f972312b8f4 ("vhost: support vhost-user")
> Cc: stable at dpdk.org
> 
> Reported-by: Xuan Ding <xuan.ding at intel.com>
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
>  lib/librte_vhost/vhost_user.c | 65 +++++++++++++++++++++--------------
>  1 file changed, 39 insertions(+), 26 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 8a8726f8b8..473fd778ca 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -99,8 +99,15 @@ close_msg_fds(struct VhostUserMsg *msg)
>  {
>  	int i;
> 
> -	for (i = 0; i < msg->fd_num; i++)
> -		close(msg->fds[i]);
> +	for (i = 0; i < msg->fd_num; i++) {
> +		int fd = msg->fds[i];
> +
> +		if (fd == -1)
> +			continue;
> +
> +		msg->fds[i] = -1;
> +		close(fd);
> +	}
>  }
> 
>  /*
> @@ -1004,7 +1011,6 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  	uint64_t alignment;
>  	uint32_t i;
>  	int populate;
> -	int fd;
> 
>  	if (validate_msg_fds(msg, memory->nregions) != 0)
>  		return RTE_VHOST_MSG_RESULT_ERR;
> @@ -1012,16 +1018,13 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  	if (memory->nregions > VHOST_MEMORY_MAX_NREGIONS) {
>  		VHOST_LOG_CONFIG(ERR,
>  			"too many memory regions (%u)\n", memory->nregions);
> -		return RTE_VHOST_MSG_RESULT_ERR;
> +		goto close_msg_fds;
>  	}
> 
>  	if (dev->mem && !vhost_memory_changed(memory, dev->mem)) {
>  		VHOST_LOG_CONFIG(INFO,
>  			"(%d) memory regions not changed\n", dev->vid);
> -
> -		close_msg_fds(msg);
> -
> -		return RTE_VHOST_MSG_RESULT_OK;
> +		goto close_msg_fds;
>  	}
> 
>  	if (dev->mem) {
> @@ -1054,7 +1057,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  				"(%d) failed to allocate memory "
>  				"for dev->guest_pages\n",
>  				dev->vid);
> -			return RTE_VHOST_MSG_RESULT_ERR;
> +			goto close_msg_fds;
>  		}
>  	}
> 
> @@ -1064,18 +1067,23 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  		VHOST_LOG_CONFIG(ERR,
>  			"(%d) failed to allocate memory for dev->mem\n",
>  			dev->vid);
> -		return RTE_VHOST_MSG_RESULT_ERR;
> +		goto free_guest_pages;
>  	}
>  	dev->mem->nregions = memory->nregions;
> 
>  	for (i = 0; i < memory->nregions; i++) {
> -		fd  = msg->fds[i];
>  		reg = &dev->mem->regions[i];
> 
>  		reg->guest_phys_addr = memory->regions[i].guest_phys_addr;
>  		reg->guest_user_addr = memory->regions[i].userspace_addr;
>  		reg->size            = memory->regions[i].memory_size;
> -		reg->fd              = fd;
> +		reg->fd              = msg->fds[i];
> +
> +		/*
> +		 * Assign invalid file descriptor value to avoid double
> +		 * closing on error path.
> +		 */
> +		msg->fds[i] = -1;
> 
>  		mmap_offset = memory->regions[i].mmap_offset;
> 
> @@ -1085,7 +1093,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  				"mmap_offset (%#"PRIx64") and memory_size "
>  				"(%#"PRIx64") overflow\n",
>  				mmap_offset, reg->size);
> -			goto err_mmap;
> +			goto free_mem_table;
>  		}
> 
>  		mmap_size = reg->size + mmap_offset;
> @@ -1098,11 +1106,11 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  		 * to avoid failure, make sure in caller to keep length
>  		 * aligned.
>  		 */
> -		alignment = get_blk_size(fd);
> +		alignment = get_blk_size(reg->fd);
>  		if (alignment == (uint64_t)-1) {
>  			VHOST_LOG_CONFIG(ERR,
>  				"couldn't get hugepage size through fstat\n");
> -			goto err_mmap;
> +			goto free_mem_table;
>  		}
>  		mmap_size = RTE_ALIGN_CEIL(mmap_size, alignment);
>  		if (mmap_size == 0) {
> @@ -1118,17 +1126,17 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  			VHOST_LOG_CONFIG(ERR, "mmap size (0x%" PRIx64 ") "
>  					"or alignment (0x%" PRIx64 ") is invalid\n",
>  					reg->size + mmap_offset, alignment);
> -			goto err_mmap;
> +			goto free_mem_table;
>  		}
> 
>  		populate = dev->async_copy ? MAP_POPULATE : 0;
>  		mmap_addr = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
> -				 MAP_SHARED | populate, fd, 0);
> +				 MAP_SHARED | populate, reg->fd, 0);
> 
>  		if (mmap_addr == MAP_FAILED) {
>  			VHOST_LOG_CONFIG(ERR,
>  				"mmap region %u failed.\n", i);
> -			goto err_mmap;
> +			goto free_mem_table;
>  		}
> 
>  		reg->mmap_addr = mmap_addr;
> @@ -1141,7 +1149,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  				VHOST_LOG_CONFIG(ERR,
>  					"adding guest pages to region %u failed.\n",
>  					i);
> -				goto err_mmap;
> +				goto free_mem_table;
>  			}
> 
>  		VHOST_LOG_CONFIG(INFO,
> @@ -1184,17 +1192,17 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  		if (read_vhost_message(main_fd, &ack_msg) <= 0) {
>  			VHOST_LOG_CONFIG(ERR,
>  				"Failed to read qemu ack on postcopy set-mem-
> table\n");
> -			goto err_mmap;
> +			goto free_mem_table;
>  		}
> 
>  		if (validate_msg_fds(&ack_msg, 0) != 0)
> -			goto err_mmap;
> +			goto free_mem_table;
> 
>  		if (ack_msg.request.master != VHOST_USER_SET_MEM_TABLE) {
>  			VHOST_LOG_CONFIG(ERR,
>  				"Bad qemu ack on postcopy set-mem-table (%d)\n",
>  				ack_msg.request.master);
> -			goto err_mmap;
> +			goto free_mem_table;
>  		}
> 
>  		/* Now userfault register and we can use the memory */
> @@ -1218,7 +1226,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  					"Failed to register ufd for region %d: (ufd
> = %d) %s\n",
>  					i, dev->postcopy_ufd,
>  					strerror(errno));
> -				goto err_mmap;
> +				goto free_mem_table;
>  			}
>  			VHOST_LOG_CONFIG(INFO,
>  				"\t userfaultfd registered for range : "
> @@ -1227,7 +1235,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  				(uint64_t)reg_struct.range.start +
>  				(uint64_t)reg_struct.range.len - 1);
>  #else
> -			goto err_mmap;
> +			goto free_mem_table;
>  #endif
>  		}
>  	}
> @@ -1249,7 +1257,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  			dev = translate_ring_addresses(dev, i);
>  			if (!dev) {
>  				dev = *pdev;
> -				goto err_mmap;
> +				goto free_mem_table;
>  			}
> 
>  			*pdev = dev;
> @@ -1260,10 +1268,15 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
> 
>  	return RTE_VHOST_MSG_RESULT_OK;
> 
> -err_mmap:
> +free_mem_table:
>  	free_mem_region(dev);
>  	rte_free(dev->mem);
>  	dev->mem = NULL;
> +free_guest_pages:
> +	rte_free(dev->guest_pages);
> +	dev->guest_pages = NULL;
> +close_msg_fds:
> +	close_msg_fds(msg);
>  	return RTE_VHOST_MSG_RESULT_ERR;
>  }
> 
> --
> 2.26.2



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