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Message-ID: <20240209203428.307351-2-edumazet@google.com>
Date: Fri, 9 Feb 2024 20:34:16 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org, eric.dumazet@...il.com,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH v3 net-next 01/13] net: annotate data-races around dev->name_assign_type
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@...gle.com>
---
net/core/dev.c | 6 +++---
net/core/net-sysfs.c | 4 ++--
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 31f2c97d19903a7b4ce92292dd53486c0043cd1b..7bba4a47231726d666348539538ae94eb248fc3a 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;
--
2.43.0.687.g38aa6559b0-goog
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