diff mbox series

[v2,net-next,01/13] net: annotate data-races around dev->name_assign_type

Message ID 20240208141154.1131622-2-edumazet@google.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: complete dev_base_lock removal | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1056 this patch: 1056
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 4 of 4 maintainers
netdev/build_clang success Errors and warnings before: 1066 this patch: 1066
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1073 this patch: 1073
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 39 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-02-09--00-00 (tests: 687)

Commit Message

Eric Dumazet Feb. 8, 2024, 2:11 p.m. UTC 
name_assign_type_show() runs locklessly, we should annotate
accesses to dev->name_assign_type.

Alternative would be to grab devnet_rename_sem semaphore
from name_assign_type_show(), but this would not bring
more accuracy.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/core/dev.c       | 6 +++---
 net/core/net-sysfs.c | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/net/core/dev.c b/net/core/dev.c
index e52e2888cccd37e0df794155004e77261c812ef9..c0db7408fa9f9a3ae9b5b83d34b50663604a5f99 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1220,13 +1220,13 @@  int dev_change_name(struct net_device *dev, const char *newname)
 			    dev->flags & IFF_UP ? " (while UP)" : "");
 
 	old_assign_type = dev->name_assign_type;
-	dev->name_assign_type = NET_NAME_RENAMED;
+	WRITE_ONCE(dev->name_assign_type, NET_NAME_RENAMED);
 
 rollback:
 	ret = device_rename(&dev->dev, dev->name);
 	if (ret) {
 		memcpy(dev->name, oldname, IFNAMSIZ);
-		dev->name_assign_type = old_assign_type;
+		WRITE_ONCE(dev->name_assign_type, old_assign_type);
 		up_write(&devnet_rename_sem);
 		return ret;
 	}
@@ -1255,7 +1255,7 @@  int dev_change_name(struct net_device *dev, const char *newname)
 			down_write(&devnet_rename_sem);
 			memcpy(dev->name, oldname, IFNAMSIZ);
 			memcpy(oldname, newname, IFNAMSIZ);
-			dev->name_assign_type = old_assign_type;
+			WRITE_ONCE(dev->name_assign_type, old_assign_type);
 			old_assign_type = NET_NAME_RENAMED;
 			goto rollback;
 		} else {
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index a09d507c5b03d24a829bf7af0b7cf1e6a0bdb65a..f4c2b82674951bbeefd880ca22c54e6a32c9f988 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -125,7 +125,7 @@  static DEVICE_ATTR_RO(iflink);
 
 static ssize_t format_name_assign_type(const struct net_device *dev, char *buf)
 {
-	return sysfs_emit(buf, fmt_dec, dev->name_assign_type);
+	return sysfs_emit(buf, fmt_dec, READ_ONCE(dev->name_assign_type));
 }
 
 static ssize_t name_assign_type_show(struct device *dev,
@@ -135,7 +135,7 @@  static ssize_t name_assign_type_show(struct device *dev,
 	struct net_device *ndev = to_net_dev(dev);
 	ssize_t ret = -EINVAL;
 
-	if (ndev->name_assign_type != NET_NAME_UNKNOWN)
+	if (READ_ONCE(ndev->name_assign_type) != NET_NAME_UNKNOWN)
 		ret = netdev_show(dev, attr, buf, format_name_assign_type);
 
 	return ret;