2014-04-29 19:33:12

by Fabian Frédérick

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Subject: [PATCH 1/1] Revert "affs: use ->kill_sb() to simplify ->put_super() and failure exits of ->mount()"

This reverts commit 842a859db26b70 due to permanent crash issues.

Sample scenario:

dd if=/dev/zero of=f1 bs=1M count=1
losetup -f f1
mount -t affs -o unknownoption /dev/loop0 mnt1
-> crash

With patch revert:
"mount: wrong fs type, bad option, bad superblock on /dev/loop0"

Cc: Alexander Viro <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Fabian Frederick <[email protected]>
---
fs/affs/super.c | 57 ++++++++++++++++++++++++++++++++-------------------------
1 file changed, 32 insertions(+), 25 deletions(-)

diff --git a/fs/affs/super.c b/fs/affs/super.c
index 6d589f2..d617b2a 100644
--- a/fs/affs/super.c
+++ b/fs/affs/super.c
@@ -49,6 +49,11 @@ affs_put_super(struct super_block *sb)
pr_debug("AFFS: put_super()\n");

cancel_delayed_work_sync(&sbi->sb_work);
+ kfree(sbi->s_prefix);
+ affs_free_bitmap(sb);
+ affs_brelse(sbi->s_root_bh);
+ kfree(sbi);
+ sb->s_fs_info = NULL;
}

static int
@@ -315,7 +320,7 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
unsigned long mount_flags;
int tmp_flags; /* fix remount prototype... */
u8 sig[4];
- int ret;
+ int ret = -EINVAL;

save_mount_options(sb, data);

@@ -411,19 +416,17 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
if (!silent)
printk(KERN_ERR "AFFS: No valid root block on device %s\n",
sb->s_id);
- return -EINVAL;
+ goto out_error;

/* N.B. after this point bh must be released */
got_root:
- /* Keep super block in cache */
- sbi->s_root_bh = root_bh;
root_block = sbi->s_root_block;

/* Find out which kind of FS we have */
boot_bh = sb_bread(sb, 0);
if (!boot_bh) {
printk(KERN_ERR "AFFS: Cannot read boot block\n");
- return -EINVAL;
+ goto out_error;
}
memcpy(sig, boot_bh->b_data, 4);
brelse(boot_bh);
@@ -472,7 +475,7 @@ got_root:
default:
printk(KERN_ERR "AFFS: Unknown filesystem on device %s: %08X\n",
sb->s_id, chksum);
- return -EINVAL;
+ goto out_error;
}

if (mount_flags & SF_VERBOSE) {
@@ -489,17 +492,22 @@ got_root:
if (sbi->s_flags & SF_OFS)
sbi->s_data_blksize -= 24;

+ /* Keep super block in cache */
+ sbi->s_root_bh = root_bh;
+ /* N.B. after this point s_root_bh must be released */
+
tmp_flags = sb->s_flags;
- ret = affs_init_bitmap(sb, &tmp_flags);
- if (ret)
- return ret;
+ if (affs_init_bitmap(sb, &tmp_flags))
+ goto out_error;
sb->s_flags = tmp_flags;

/* set up enough so that it can read an inode */

root_inode = affs_iget(sb, root_block);
- if (IS_ERR(root_inode))
- return PTR_ERR(root_inode);
+ if (IS_ERR(root_inode)) {
+ ret = PTR_ERR(root_inode);
+ goto out_error;
+ }

if (AFFS_SB(sb)->s_flags & SF_INTL)
sb->s_d_op = &affs_intl_dentry_operations;
@@ -509,11 +517,22 @@ got_root:
sb->s_root = d_make_root(root_inode);
if (!sb->s_root) {
printk(KERN_ERR "AFFS: Get root inode failed\n");
- return -ENOMEM;
+ goto out_error;
}

pr_debug("AFFS: s_flags=%lX\n",sb->s_flags);
return 0;
+
+ /*
+ * Begin the cascaded cleanup ...
+ */
+out_error:
+ kfree(sbi->s_bitmap);
+ affs_brelse(root_bh);
+ kfree(sbi->s_prefix);
+ kfree(sbi);
+ sb->s_fs_info = NULL;
+ return ret;
}

static int
@@ -601,23 +620,11 @@ static struct dentry *affs_mount(struct file_system_type *fs_type,
return mount_bdev(fs_type, flags, dev_name, data, affs_fill_super);
}

-static void affs_kill_sb(struct super_block *sb)
-{
- struct affs_sb_info *sbi = AFFS_SB(sb);
- kill_block_super(sb);
- if (sbi) {
- affs_free_bitmap(sb);
- affs_brelse(sbi->s_root_bh);
- kfree(sbi->s_prefix);
- kfree(sbi);
- }
-}
-
static struct file_system_type affs_fs_type = {
.owner = THIS_MODULE,
.name = "affs",
.mount = affs_mount,
- .kill_sb = affs_kill_sb,
+ .kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("affs");
--
1.8.4.5


2014-04-29 22:30:25

by Andrew Morton

[permalink] [raw]
Subject: Re: [PATCH 1/1] Revert "affs: use ->kill_sb() to simplify ->put_super() and failure exits of ->mount()"

On Tue, 29 Apr 2014 21:35:12 +0200 Fabian Frederick <[email protected]> wrote:

> This reverts commit 842a859db26b70 due to permanent crash issues.
>
> Sample scenario:
>
> dd if=/dev/zero of=f1 bs=1M count=1
> losetup -f f1
> mount -t affs -o unknownoption /dev/loop0 mnt1
> -> crash

Thanks for the bug report ;)

> With patch revert:
> "mount: wrong fs type, bad option, bad superblock on /dev/loop0"

But reverting is premature. With this info Al will presumably fix this up.

2014-04-30 05:10:56

by Fabian Frédérick

[permalink] [raw]
Subject: Re: [PATCH 1/1] Revert "affs: use ->kill_sb() to simplify ->put_super() and failure exits of ->mount()"

On Tue, 29 Apr 2014 15:30:22 -0700
Andrew Morton <[email protected]> wrote:

> On Tue, 29 Apr 2014 21:35:12 +0200 Fabian Frederick <[email protected]> wrote:
>
> > This reverts commit 842a859db26b70 due to permanent crash issues.
> >
> > Sample scenario:
> >
> > dd if=/dev/zero of=f1 bs=1M count=1
> > losetup -f f1
> > mount -t affs -o unknownoption /dev/loop0 mnt1
> > -> crash
>
> Thanks for the bug report ;)
Sorry, it was only tested under X window and box was completely frozen.
I guess Al can test with the simple steps above or I can make a complete console report.

>
> > With patch revert:
> > "mount: wrong fs type, bad option, bad superblock on /dev/loop0"
>
> But reverting is premature. With this info Al will presumably fix this up.
Of course :)