Re: files_lock deadlock?

[Alexander Nyberg <alexn@telia.com>]

tis 2005-07-19 klockan 18:45 +0200 skrev Martin Wilck:
> Hello,
> 
> I apologize in advance if this is a dummy question. My web search turned 
> up nothing, so I'm trying it here.
> 
> We came across the following error message:
> 
> Kernelpanic - not syncing: fs/proc/
> Generic.c:521: spin_lock(fs/file_table.c:ffffffff80420280)
> Already locked by fs/file_table.c/204
> 
> This shows a locking problem with the files_lock on a UP kernel with 
> spinlock debugging enabled.
> 
> I noticed that files_lock is only protected with spin_lock() 
> (file_list_lock(), include/linux/fs.h). Is it possible that this should 
> be changed to spin_lock_irq()) or spin_lock_irqsave()? Or am I misssing 
> something obvious?

spin_lock_irqsave is only needed when a lock is taken both in normal
context and in interrupt context. Clearly this lock is not intended to
be taken in interrupt context. 

I'll take a look, that spinlock debugging information unfortunately
doesn't give too much info :|