Re: Bug in Kernel 6.8.x, 6.9.x Causing Trace/Panic During Shutdown/Reboot

[Ilkka Naulapää]

applied your patch and here's the output.

--Ilkka

On Wed, May 29, 2024 at 10:48 PM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> On Wed, 29 May 2024 14:47:57 -0400
> Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> > Let me make a debug patch (that crashes on this issue) for that kernel,
> > and perhaps you could bisect it?
>
> Can you try this on 6.6-rc1 and see if it gives you any other splats?
>
> Hmm, you can switch it to WARN_ON and that way it may not crash the
> machine, and you can use dmesg to get the output.
>
> Thanks,
>
> -- Steve
>
>
> diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
> index de5b72216b1a..a090495e78c9 100644
> --- a/fs/tracefs/inode.c
> +++ b/fs/tracefs/inode.c
> @@ -39,13 +39,17 @@ static struct inode *tracefs_alloc_inode(struct super_block *sb)
>                 return NULL;
>
>         ti->flags = 0;
> +       ti->magic = 20240823;
>
>         return &ti->vfs_inode;
>  }
>
>  static void tracefs_free_inode(struct inode *inode)
>  {
> -       kmem_cache_free(tracefs_inode_cachep, get_tracefs(inode));
> +       struct tracefs_inode *ti = get_tracefs(inode);
> +
> +       BUG_ON(ti->magic != 20240823);
> +       kmem_cache_free(tracefs_inode_cachep, ti);
>  }
>
>  static ssize_t default_read_file(struct file *file, char __user *buf,
> @@ -147,16 +151,6 @@ static const struct inode_operations tracefs_dir_inode_operations = {
>         .rmdir          = tracefs_syscall_rmdir,
>  };
>
> -struct inode *tracefs_get_inode(struct super_block *sb)
> -{
> -       struct inode *inode = new_inode(sb);
> -       if (inode) {
> -               inode->i_ino = get_next_ino();
> -               inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
> -       }
> -       return inode;
> -}
> -
>  struct tracefs_mount_opts {
>         kuid_t uid;
>         kgid_t gid;
> @@ -384,6 +378,7 @@ static void tracefs_dentry_iput(struct dentry *dentry, struct inode *inode)
>                 return;
>
>         ti = get_tracefs(inode);
> +       BUG_ON(ti->magic != 20240823);
>         if (ti && ti->flags & TRACEFS_EVENT_INODE)
>                 eventfs_set_ef_status_free(dentry);
>         iput(inode);
> @@ -568,6 +563,18 @@ struct dentry *eventfs_end_creating(struct dentry *dentry)
>         return dentry;
>  }
>
> +struct inode *tracefs_get_inode(struct super_block *sb)
> +{
> +       struct inode *inode = new_inode(sb);
> +
> +       BUG_ON(sb->s_op != &tracefs_super_operations);
> +       if (inode) {
> +               inode->i_ino = get_next_ino();
> +               inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
> +       }
> +       return inode;
> +}
> +
>  /**
>   * tracefs_create_file - create a file in the tracefs filesystem
>   * @name: a pointer to a string containing the name of the file to create.
> diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
> index 69c2b1d87c46..9f6f303a9e58 100644
> --- a/fs/tracefs/internal.h
> +++ b/fs/tracefs/internal.h
> @@ -9,6 +9,7 @@ enum {
>  struct tracefs_inode {
>         unsigned long           flags;
>         void                    *private;
> +       unsigned long           magic;
>         struct inode            vfs_inode;
>  };
>

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