[PATCH v2 1/1] eal/linux: reject --huge-dir not parent of mountpt
Ashish Sadanandan
ashish.sadanandan at gmail.com
Wed Jan 4 01:00:30 CET 2023
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 at nutanix.com
Cc: stable at dpdk.org
Signed-off-by: Ashish Sadanandan <ashish.sadanandan at 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);
+
/*
* 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] != '/') {
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 */
--
2.27.0
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