Re: 2.6.12-rc4-mm1

[steve <steve@friservices.com>]

David Woodhouse wrote:

>On Fri, 2005-05-13 at 09:53 -0500, steve would have written, if his mail
>client hadn't been broken:
>  
>
>>a bug that appeared after running for about 2 hours:
>>
>>May 13 09:32:34 localhost kernel: BUG: atomic counter underflow at:
>>May 13 09:32:34 localhost kernel:  [reiserfs_clear_inode+129/176] reiserfs_clear_inode+0x81/0xb0
>>May 13 09:32:34 localhost kernel:  [clear_inode+228/304] clear_inode+0xe4/0x130
>>May 13 09:32:34 localhost kernel:  [dispose_list+112/304] dispose_list+0x70/0x130
>>May 13 09:32:34 localhost kernel:  [prune_icache+191/432] prune_icache+0xbf/0x1b0
>>May 13 09:32:34 localhost kernel:  [shrink_icache_memory+20/64] shrink_icache_memory+0x14/0x40
>>May 13 09:32:34 localhost kernel:  [shrink_slab+345/416] shrink_slab+0x159/0x1a0
>>May 13 09:32:34 localhost kernel:  [balance_pgdat+695/944] balance_pgdat+0x2b7/0x3b0
>>May 13 09:32:34 localhost kernel:  [kswapd+210/240] kswapd+0xd2/0xf0 
>>May 13 09:32:34 localhost kernel:  [autoremove_wake_function+0/80] autoremove_wake_function+0x0/0x50
>>May 13 09:32:34 localhost kernel:  [ret_from_fork+6/20] ret_from_fork+0x6/0x14
>>May 13 09:32:34 localhost kernel:  [autoremove_wake_function+0/80] autoremove_wake_function+0x0/0x50
>>May 13 09:32:34 localhost kernel:  [kswapd+0/240] kswapd+0x0/0xf0
>>May 13 09:32:34 localhost kernel:  [kernel_thread_helper+5/24] kernel_thread_helper+0x5/0x18
>>    
>>
>
>Hmmm. We're hitting that bug when posix_acl_release() decrements the
>refcount on one of the inode's ACLs and it goes negative.
>
>First glance at this had me suspecting that we were somehow calling
>clear_inode() twice... but since we clear the pointer to the ACL after
>calling posix_acl_release(), that seems unlikely -- unless you managed
>to get two CPUs in reiserfs_clear_inode() simultaneously for the same
>inode. Is this SMP? Is preempt enabled?
>
>Can you reproduce it? If so, does it go away if you revert one or both
>of these:
>
>ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.12-rc4/2.6.12-rc4-mm1/broken-out/vfs-bugfix-two-read_inode-calles-without.patch
>ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.12-rc4/2.6.12-rc4-mm1/broken-out/__wait_on_freeing_inode-fix.patch
>
>  
>
okay, reproduced after a couple hours of running (nothing intensive), 
then doing a grep blah -r /*

here's the new output:
May 13 19:54:16 localhost kernel: BUG: atomic counter underflow at:
May 13 19:54:16 localhost kernel:  [reiserfs_clear_inode+129/176] 
reiserfs_clear_inode+0x81/0xb0
May 13 19:54:16 localhost kernel:  [clear_inode+228/304] 
clear_inode+0xe4/0x130
May 13 19:54:16 localhost kernel:  [dispose_list+112/304] 
dispose_list+0x70/0x130
May 13 19:54:16 localhost kernel:  [prune_icache+191/432] 
prune_icache+0xbf/0x1b0
May 13 19:54:16 localhost kernel:  [shrink_icache_memory+20/64] 
shrink_icache_memory+0x14/0x40
May 13 19:54:16 localhost kernel:  [shrink_slab+345/416] 
shrink_slab+0x159/0x1a0
May 13 19:54:16 localhost kernel:  [try_to_free_pages+226/416] 
try_to_free_pages+0xe2/0x1a0
May 13 19:54:16 localhost kernel:  [__alloc_pages+383/960] 
__alloc_pages+0x17f/0x3c0
May 13 19:54:16 localhost kernel:  [__do_page_cache_readahead+285/352] 
__do_page_cache_readahead+0x11d/0x160
May 13 19:54:16 localhost kernel:  
[blockable_page_cache_readahead+81/208] 
blockable_page_cache_readahead+0x51/0xd0
May 13 19:54:16 localhost kernel:  [make_ahead_window+112/176] 
make_ahead_window+0x70/0xb0
May 13 19:54:16 localhost kernel:  [page_cache_readahead+169/384] 
page_cache_readahead+0xa9/0x180
May 13 19:54:16 localhost kernel:  [file_read_actor+198/224] 
file_read_actor+0xc6/0xe0
May 13 19:54:16 localhost kernel:  [do_generic_mapping_read+1446/1472] 
do_generic_mapping_read+0x5a6/0x5c0
May 13 19:54:16 localhost kernel:  [pg0+542324240/1068651520] 
ieee80211_recv_mgmt+0xed0/0x1d90 [wlan]
May 13 19:54:16 localhost kernel:  [file_read_actor+0/224] 
file_read_actor+0x0/0xe0
May 13 19:54:16 localhost kernel:  [__generic_file_aio_read+484/544] 
__generic_file_aio_read+0x1e4/0x220
May 13 19:54:16 localhost kernel:  [file_read_actor+0/224] 
file_read_actor+0x0/0xe0
May 13 19:54:16 localhost kernel:  [generic_file_read+149/176] 
generic_file_read+0x95/0xb0
May 13 19:54:16 localhost kernel:  [try_to_wake_up+166/192] 
try_to_wake_up+0xa6/0xc0
May 13 19:54:16 localhost kernel:  [autoremove_wake_function+0/80] 
autoremove_wake_function+0x0/0x50
May 13 19:54:16 localhost kernel:  [schedule+791/1616] schedule+0x317/0x650
May 13 19:54:16 localhost kernel:  [vfs_read+156/336] vfs_read+0x9c/0x150
May 13 19:54:16 localhost kernel:  [sys_read+71/128] sys_read+0x47/0x80
May 13 19:54:16 localhost kernel:  [syscall_call+7/11] syscall_call+0x7/0xb


i'll recompile without those two patches, and try it again.

Steve