Memory leak problem with JFFS2

[Frederic Giasson]

You have the right procedure to reproduce the problem ( vmstat ; while true
; do mount -t jffs2 mtd0 /mnt/spare ; ).  I can reproduce the problem using
this line on my system.

I updated my JFFS2 code with the lastest from CVS, and I am using kernel
2.4.19-rc2, and the problem is still there.  Do you think you could do the
same test under 2.4.19-rc2?

Thanks,

Frédéric Giasson 

|-----Original Message-----
|From: David Woodhouse [mailto:dwmw2 at infradead.org]
|Sent: Wednesday, July 31, 2002 11:17 AM
|To: Frederic Giasson
|Cc: linux-mtd at lists.infradead.org
|Subject: Re: Memory leak problem with JFFS2 
|
|
|
|fgiasson at mediatrix.com said:
|>  I took some time to track down the memory leak that happens after
|> umount. First I compiled JFFS2 as a module and loaded/unloaded it
|> doing a mount/umount in between.  No BUG occured, meaning 
|that no slab
|> object is still allocated when I unload the module.  Then I
|> investigated around the kmalloc/kfree, but I found nothing.  I put
|> traces and counters each time a kmalloc / kfree was called, and the
|> number of kmalloc and kfree is balanced. Therefore, I can conclude
|> than the memory leak is not an allocated object still allocated at
|> umount time and is not a kmalloc without kfree neither. Do you have
|> any other idea about it?  This is not very likely to be the mount /
|> umount mechanism that could cause the leak, I tried mounting and
|> unmounting NFS and the memory usage before and after does 
|not change. 
|
|Can you remind me what you have to do to reproduce this?
|
|With 2.5.29, which contains the latest JFFS2 code from CVS...
|
|# vmstat ; while true ; do mount -t jffs2 mtd0 /mnt/spare ; 
|sync ; umount /mnt/spare ; vmstat|tail -1 ; done
|   procs                      memory    swap          io     
|system         cpu
| r  b  w   swpd   free   buff  cache  si  so    bi    bo   in  
|  cs  us  sy  id
| 0  0  0      0  81800      0  26244   0   0     2     5 1003  
|   8   2   3  95
| 1  0  0      0  81696      0  26244   0   0     2     5 1003  
|   8   2   3  95
| 1  0  0      0  81700      0  26244   0   0     2     5 1003  
|   9   2   3  95
| 1  0  0      0  81712      0  26244   0   0     2     5 1003  
|   9   2   3  95
| 1  0  0      0  81696      0  26244   0   0     2     5 1003  
|   9   2   3  95
| 2  0  0      0  81704      0  26244   0   0     2     5 1003  
|   9   2   3  95
| 2  0  0      0  81708      0  26248   0   0     2     5 1003  
|   9   2   3  95
| 2  0  0      0  81696      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  0      0  81696      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  0      0  81712      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  1      0  81688      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  1      0  81696      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  0      0  81708      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  0      0  81692      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  0      0  81696      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  0      0  81708      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  0      0  81692      0  26248   0   0     2     5 1003  
|  10   2   3  95
| 2  0  0      0  81696      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  0      0  81708      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  0      0  81680      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  0      0  81724      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  0      0  81712      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  0      0  81704      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  0      0  81696      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  1      0  81708      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  0      0  81688      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  0      0  81696      0  26248   0   0     2     5 1003  
|  11   2   3  95
| 2  0  0      0  81708      0  26248   0   0     2     5 1003  
|  12   2   3  95
| 2  0  0      0  81692      0  26248   0   0     2     5 1003  
|  12   2   3  95
| 2  0  0      0  81696      0  26248   0   0     2     5 1003  
|  12   2   3  95
| 2  0  0      0  81708      0  26248   0   0     2     5 1003  
|  12   2   3  95
| 2  0  0      0  81692      0  26248   0   0     2     5 1003  
|  12   2   3  95
| 2  0  0      0  81696      0  26248   0   0     2     5 1003  
|  12   2   3  95
| 2  0  0      0  81708      0  26248   0   0     2     5 1003  
|  12   2   3  95
|Interrupt
|
|> Between, we still don't know why doing a sync after an "rm" command
|> triggers the garbage collector.  Do you have any other clue 
|about it? 
|
|Not off-hand. 
|
|--
|dwmw2
|
|
|