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

[Linux regression tracking (Thorsten Leemhuis)]

On 13.06.24 09:32, Ilkka Naulapää wrote:
> On Wed, Jun 12, 2024 at 6:56 PM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>> On Wed, 12 Jun 2024 15:36:22 +0200
>> "Linux regression tracking (Thorsten Leemhuis)" <regressions@xxxxxxxxxxxxx> wrote:
>>>
>>> Ilkka or Steven, what happened to this? This thread looks stalled. I
>>> also was unsuccessful when looking for other threads related to this
>>> report or the culprit. Did it fall through the cracks or am I missing
>>> something here?
>
>> Honesty, I have no idea where the bug is. I can't reproduce it. [...]

Steven, thx for the update! And yeah, that's how it sometimes is. Given
that we haven't seen similar reports (at least afaics) it's nothing I
worry much about.

> ok, so if you don't have any idea where this bug is after those debug
> patches, I'll try to find some time to bisect it as a last resort.
> Stay tuned.

Yeah, that would be great help. Thank you, too!

Ciao, Thorsten

>>> On 02.06.24 09:32, Ilkka Naulapää wrote:
>>>> sorry longer delay, been a bit busy but here is the result from that
>>>> new patch. Only applied this patch so if the previous one is needed
>>>> also, let me know and I'll rerun it.
>>>>
>>>> --Ilkka
>>>>
>>>> On Thu, May 30, 2024 at 5:00 PM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>>>>>
>>>>> On Thu, 30 May 2024 16:02:37 +0300
>>>>> Ilkka Naulapää <digirigawa@xxxxxxxxx> wrote:
>>>>>
>>>>>> applied your patch and here's the output.
>>>>>>
>>>>>
>>>>> Unfortunately, it doesn't give me any new information. I added one more
>>>>> BUG on, want to try this? Otherwise, I'm pretty much at a lost. :-/
>>>>>
>>>>> -- 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..9059b8b11bb6 100644
>>>>> --- a/fs/tracefs/internal.h
>>>>> +++ b/fs/tracefs/internal.h
>>>>> @@ -9,12 +9,15 @@ enum {
>>>>>  struct tracefs_inode {
>>>>>         unsigned long           flags;
>>>>>         void                    *private;
>>>>> +       unsigned long           magic;
>>>>>         struct inode            vfs_inode;
>>>>>  };
>>>>>
>>>>>  static inline struct tracefs_inode *get_tracefs(const struct inode *inode)
>>>>>  {
>>>>> -       return container_of(inode, struct tracefs_inode, vfs_inode);
>>>>> +       struct tracefs_inode *ti = container_of(inode, struct tracefs_inode, vfs_inode);
>>>>> +       BUG_ON(ti->magic != 20240823);
>>>>> +       return ti;
>>>>>  }
>>>>>
>>>>>  struct dentry *tracefs_start_creating(const char *name, struct dentry *parent);
>>
> 
>