patch 'eal/linux: fix hugetlbfs sub-directories discovery' has been queued to stable release 22.11.2

[Xueming Li]

Hi,

FYI, your patch has been queued to stable release 22.11.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 03/01/23. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://git.dpdk.org/dpdk-stable/log/?h=22.11-staging

This queued commit can be viewed at:
https://git.dpdk.org/dpdk-stable/commit/?h=22.11-staging&id=acacb53810bc6949ab5517b75e947cdd6e482e06

Thanks.

Xueming Li <xuemingl at nvidia.com>

---
>From acacb53810bc6949ab5517b75e947cdd6e482e06 Mon Sep 17 00:00:00 2001
From: Ashish Sadanandan <ashish.sadanandan at gmail.com>
Date: Sun, 8 Jan 2023 18:52:39 -0700
Subject: [PATCH] eal/linux: fix hugetlbfs sub-directories discovery
Cc: Xueming Li <xuemingl at nvidia.com>

[ upstream commit f9d1ef28619a2dd16cafca36f5a5ca6d3315c5fc ]

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")

Signed-off-by: Ashish Sadanandan <ashish.sadanandan at gmail.com>
Reviewed-by: John Levon <john.levon at nutanix.com>
Tested-by: Julien Meunier <julien.meunier at nokia.com>
---
 lib/eal/linux/eal_hugepage_info.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/lib/eal/linux/eal_hugepage_info.c b/lib/eal/linux/eal_hugepage_info.c
index 24411d9c5b..581d9dfc91 100644
--- a/lib/eal/linux/eal_hugepage_info.c
+++ b/lib/eal/linux/eal_hugepage_info.c
@@ -214,6 +214,8 @@ get_hugepage_dir(uint64_t hugepage_sz, char *hugedir, int len)
 	char buf[BUFSIZ];
 	const struct internal_config *internal_conf =
 		eal_get_internal_configuration();
+	const size_t hugepage_dir_len = (internal_conf->hugepage_dir != NULL) ?
+		strlen(internal_conf->hugepage_dir) : 0;
 	struct stat st;

 	/*
@@ -233,6 +235,7 @@ get_hugepage_dir(uint64_t hugepage_sz, char *hugedir, int len)

 	while (fgets(buf, sizeof(buf), fd)){
 		const char *pagesz_str;
+		size_t mountpt_len = 0;

 		if (rte_strsplit(buf, sizeof(buf), splitstr, _FIELDNAME_MAX,
 				split_tok) != _FIELDNAME_MAX) {
@@ -265,12 +268,16 @@ get_hugepage_dir(uint64_t hugepage_sz, char *hugedir, int len)
 			break;
 		}

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

@@ -278,7 +285,7 @@ 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 */

--
2.25.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2023-02-27 14:08:43.458882900 +0800
+++ 0080-eal-linux-fix-hugetlbfs-sub-directories-discovery.patch	2023-02-27 14:08:40.799237000 +0800
@@ -1 +1 @@
-From f9d1ef28619a2dd16cafca36f5a5ca6d3315c5fc Mon Sep 17 00:00:00 2001
+From acacb53810bc6949ab5517b75e947cdd6e482e06 Mon Sep 17 00:00:00 2001
@@ -4,0 +5,3 @@
+Cc: Xueming Li <xuemingl at nvidia.com>
+
+[ upstream commit f9d1ef28619a2dd16cafca36f5a5ca6d3315c5fc ]
@@ -32 +34,0 @@
-Cc: stable at dpdk.org