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From: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
To: Ashish Sadanandan <ashish.sadanandan@gmail.com>
Cc: dev@dpdk.org, john.levon@nutanix.com, stable@dpdk.org
Subject: Re: [PATCH v2 1/1] eal/linux: reject --huge-dir not parent of mountpt
Date: Wed, 4 Jan 2023 14:24:56 +0300	[thread overview]
Message-ID: <20230104142456.320fc95a@sovereign> (raw)
In-Reply-To: <20230104000030.187857-1-ashish.sadanandan@gmail.com>

2023-01-03 17:00 (UTC-0700), Ashish Sadanandan:
> The code added for allowing --huge-dir to specify hugetlbfs
> sub-directories has a bug where it incorrectly matches mounts that
> contain a prefix of the specified --huge-dir.
> 
> Consider --huge-dir=/dev/hugepages1G is passed to rte_eal_init. Given
> the following hugetlbfs mounts
> 
> $ mount | grep hugetlbfs
> hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime,pagesize=2M)
> hugetlbfs on /dev/hugepages1G type hugetlbfs (rw,relatime,pagesize=1024M)
> hugetlbfs on /mnt/huge type hugetlbfs (rw,relatime,pagesize=2M)
> 
> get_hugepage_dir is first called with hugepage_sz=2097152. While
> iterating over all mount points, /dev/hugepages is incorrectly
> determined to be a match because it's a prefix of --huge-dir. The caller
> then obtains an exclusive lock on --huge-dir.
> 
> In the next call to get_hugepage_dir, hugepage_sz=1073741824. This call
> correctly determines /dev/hugepages1G is a match. The caller again
> attempts to obtain an exclusive lock on --huge-dir and deadlocks because
> it's already holding a lock.
> 
> This has been corrected by ensuring any matched mount point is either an
> exact match or a parent path of --huge-dir.
> 
> Fixes: 24d5a1ce6b85 ("eal/linux: allow hugetlbfs sub-directories")
> Cc: john.levon@nutanix.com
> Cc: stable@dpdk.org
> Signed-off-by: Ashish Sadanandan <ashish.sadanandan@gmail.com>

Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>

> ---
>  lib/eal/linux/eal_hugepage_info.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/eal/linux/eal_hugepage_info.c b/lib/eal/linux/eal_hugepage_info.c
> index a1b6cb31ff..180abd930c 100644
> --- a/lib/eal/linux/eal_hugepage_info.c
> +++ b/lib/eal/linux/eal_hugepage_info.c
> @@ -265,12 +265,23 @@ get_hugepage_dir(uint64_t hugepage_sz, char *hugedir, int len)
>  			break;
>  		}
>  
> +		size_t mountpt_len = strlen(splitstr[MOUNTPT]);
> +		size_t hugepage_dir_len = strlen(internal_conf->hugepage_dir);

The second one can be done before the loop.
Please declare all variables at the beginning of the block per code style.

> +
>  		/*
>  		 * Ignore any mount that doesn't contain the --huge-dir
>  		 * directory.
>  		 */
>  		if (strncmp(internal_conf->hugepage_dir, splitstr[MOUNTPT],
> -			strlen(splitstr[MOUNTPT])) != 0) {
> +			mountpt_len) != 0) {
> +			continue;
> +		}
> +		/*
> +		 * Ignore any mount where hugepage_dir is not a parent path of
> +		 * the mount
> +		 */
> +		else if(hugepage_dir_len > mountpt_len &&
> +			internal_conf->hugepage_dir[mountpt_len] != '/') {

Nit: maybe a single comment for both conditions would be more clear:

/*
 * Ignore any mount that is not --huge-dir or its subdirectory.
 */

>  			continue;
>  		}
>  
> @@ -278,7 +289,7 @@ get_hugepage_dir(uint64_t hugepage_sz, char *hugedir, int len)
>  		 * We found a match, but only prefer it if it's a longer match
>  		 * (so /mnt/1 is preferred over /mnt for matching /mnt/1/2)).
>  		 */
> -		if (strlen(splitstr[MOUNTPT]) > strlen(found))
> +		if (mountpt_len > strlen(found))
>  			strlcpy(found, splitstr[MOUNTPT], len);
>  	} /* end while fgets */

  reply	other threads:[~2023-01-04 11:25 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-03 18:57 [PATCH 1/1] eal/linux: reject mountpt shorter than --huge-dir Ashish Sadanandan
2023-01-03 23:53 ` Ashish Sadanandan
2023-01-04  0:00 ` [PATCH v2 1/1] eal/linux: reject --huge-dir not parent of mountpt Ashish Sadanandan
2023-01-04 11:24   ` Dmitry Kozlyuk [this message]
2023-01-04 18:17     ` Ashish Sadanandan
2023-01-04 16:22   ` John Levon
2023-01-04 18:17     ` Ashish Sadanandan
2023-01-04 18:17 ` [PATCH v3 " Ashish Sadanandan
2023-01-09  1:52 ` [PATCH v4 1/1] eal/linux: reject mountpt not parent of --huge-dir Ashish Sadanandan
2023-01-11 12:11   ` John Levon
2023-01-16 18:25     ` Ashish Sadanandan
2023-02-10 11:04       ` David Marchand
2023-02-10 11:01   ` David Marchand

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