From: John Groves <John@Groves.net>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
linux-fsdevel@vger.kernel.org
Cc: John Groves <John@Groves.net>, John Groves <jgroves@micron.com>,
john@jagalactic.com, John Groves <john@groves.net>
Subject: [PATCH 1/1] sget_dev() bug fix: dev_t passed by value but stored via stack address
Date: Tue, 9 Apr 2024 18:31:44 -0500 [thread overview]
Message-ID: <7a37d4832e0c2e7cfe8000b0bf47dcc2c50d78d0.1712704849.git.john@groves.net> (raw)
In-Reply-To: <cover.1712704849.git.john@groves.net>
The ref vs. value logic used by sget_dev() was ungood, storing the
stack address of the key (dev_t) rather than the value of the key.
This straightens that out.
In the sget_dev() path, the (void *)data passed to the test and set
helpers should be the value of the dev_t, not its address.
Signed-off-by: John Groves <john@groves.net>
---
fs/super.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/fs/super.c b/fs/super.c
index 69ce6c600968..b4ef775e95da 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1308,7 +1308,9 @@ EXPORT_SYMBOL(get_tree_keyed);
static int set_bdev_super(struct super_block *s, void *data)
{
- s->s_dev = *(dev_t *)data;
+ u64 devno = (u64)data;
+
+ s->s_dev = (dev_t)devno;
return 0;
}
@@ -1319,8 +1321,10 @@ static int super_s_dev_set(struct super_block *s, struct fs_context *fc)
static int super_s_dev_test(struct super_block *s, struct fs_context *fc)
{
+ u64 devno = (u64)fc->sget_key;
+
return !(s->s_iflags & SB_I_RETIRED) &&
- s->s_dev == *(dev_t *)fc->sget_key;
+ s->s_dev == (dev_t)devno;
}
/**
@@ -1345,7 +1349,9 @@ static int super_s_dev_test(struct super_block *s, struct fs_context *fc)
*/
struct super_block *sget_dev(struct fs_context *fc, dev_t dev)
{
- fc->sget_key = &dev;
+ u64 devno = (u64)dev;
+
+ fc->sget_key = (void *)devno;
return sget_fc(fc, super_s_dev_test, super_s_dev_set);
}
EXPORT_SYMBOL(sget_dev);
@@ -1637,13 +1643,15 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
struct super_block *s;
int error;
dev_t dev;
+ u64 devno;
error = lookup_bdev(dev_name, &dev);
if (error)
return ERR_PTR(error);
+ devno = (u64)dev;
flags |= SB_NOSEC;
- s = sget(fs_type, test_bdev_super, set_bdev_super, flags, &dev);
+ s = sget(fs_type, test_bdev_super, set_bdev_super, flags, (void *)devno);
if (IS_ERR(s))
return ERR_CAST(s);
--
2.43.0
next prev parent reply other threads:[~2024-04-09 23:31 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-09 23:31 [PATCH 0/1] sget_dev() minor bug fix John Groves
2024-04-09 23:31 ` John Groves [this message]
2024-04-10 9:18 ` [PATCH 1/1] sget_dev() bug fix: dev_t passed by value but stored via stack address kernel test robot
2024-04-10 10:16 ` Christian Brauner
2024-04-10 13:38 ` John Groves
2024-04-10 15:23 ` Christian Brauner
2024-04-10 21:24 ` John Groves
2024-04-17 5:06 ` kernel test robot
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