Re: [discuss] Re: 2.6.16-rc5-mm3: spinlock bad magic on CPU#0 on AMD64

[Andrew Morton <akpm@osdl.org>]

"Rafael J. Wysocki" <rjw@sisk.pl> wrote:
>
>  Done, and now it looks like this:

Helps a lot, thanks.

>  BUG: spinlock bad magic on CPU#0, soffice.bin/5192
>   lock: ffff81005f79ae28, .magic: 000001ff, .owner: 1..1..|1. |1.|1..|1.___1..|1..1. 1./-1,
>  .owner_cpu: -2141838208
> 
>  Call Trace: <ffffffff80210383>{__alloc_pages+99} <ffffffff802156c3>{spin_bug+195}
>         <ffffffff802077dc>{_raw_spin_lock+44} <ffffffff80270a4e>{_spin_lock+30}
>         <ffffffff8033712d>{journal_extend+77} <ffffffff80327255>{ext3_get_block+165}
>         <ffffffff8022c2f9>{do_mpage_readpage+425} <ffffffff80270cc4>{_write_unlock_irq+20}
>         <ffffffff8020cce2>{add_to_page_cache+162} <ffffffff8023fdee>{mpage_readpages+254}
>         <ffffffff803271b0>{ext3_get_block+0} <ffffffff803271b0>{ext3_get_block+0}
>         <ffffffff803146df>{get_cnode+95} <ffffffff8020a3bb>{get_page_from_freelist+619}
>         <ffffffff80210383>{__alloc_pages+99} <ffffffff80323c1a>{ext3_readpages+26}
>         <ffffffff80214030>{__do_page_cache_readahead+416} <ffffffff80213c12>{poison_obj+66}
>         <ffffffff80232058>{wake_up_bit+40} <ffffffff80243152>{unlock_buffer+18}
>         <ffffffff80315bb8>{reiserfs_prepare_for_journal+104}
>         <ffffffff802b6ab4>{do_page_cache_readahead+100} <ffffffff80215942>{filemap_nopage+322}
>         <ffffffff80208b2c>{__handle_mm_fault+1004} <ffffffff80270e7d>{_spin_unlock_irqrestore+29}
>         <ffffffff8020ae99>{do_page_fault+1257} <ffffffff8026af8d>{error_exit+0}
>         <ffffffff802ffb40>{reiserfs_copy_from_user_to_file_region+80}
>         <ffffffff80302446>{reiserfs_file_write+6102} <ffffffff802f8f4e>{reiserfs_add_entry+1054}
>         <ffffffff8033c1ff>{journal_cancel_revoke+351} <ffffffff80213c12>{poison_obj+66}
>         <ffffffff80236d27>{cache_free_debugcheck+711} <ffffffff80335734>{journal_stop+772}
>         <ffffffff80270f30>{_spin_unlock+16} <ffffffff802193a2>{vfs_write+226}
>         <ffffffff80219c80>{sys_write+80} <ffffffff8026d234>{cstar_do_call+27}
>  BUG: spinlock lockup on CPU#0, soffice.bin/5192, ffff81005f79ae28

It's a pretty vile backtrace.  I supposed you have CONFIG_FRAME_POINTER=n.

Still.  It seems that what's happened is that we took a pagefault while
reiserfs had a transaction open.  The fault is against a mmapped ext3 file
and we ended up in the recently-reworked ext3_get_block() which tests
journal_current_handle() to work out whether we're in a write or a read. 
oops.  The presence of reiserfs journal_info makes it decide it's a write,
not a read so it starts treating a reiserfs journal_info as an ext3 one.

The code used to work OK because it was only for direct-IO, which doesn't
get recurred into like this.  But it got used for regular I/O in -mm.

This should fix:

--- devel/fs/ext3/inode.c~ext3-get-blocks-maping-multiple-blocks-at-a-once-journal-reentry-fix	2006-03-12 14:25:04.000000000 -0800
+++ devel-akpm/fs/ext3/inode.c	2006-03-12 14:25:04.000000000 -0800
@@ -830,7 +830,7 @@ ext3_direct_io_get_blocks(struct inode *
 	handle_t *handle = journal_current_handle();
 	int ret = 0;
 
-	if (!handle)
+	if (!create)
 		goto get_block;		/* A read */
 
 	if (max_blocks == 1)
_