geli(4) memory leak

[Mikolaj Golub]

On Fri, 1 Apr 2011 19:43:54 +0200 Victor Balada Diaz wrote:

 VBD> On Sat, Mar 26, 2011 at 01:33:48AM +0100, Victor Balada Diaz wrote:
 >> Hello,
 >> 
 >> I'm trying to setup a new geli disk and i'm seeing what looks like a memory leak.
 >> After initializing the device i've tried to do the dd command from /dev/random
 >> like this one:
 >> 
 >> dd if=/dev/random of=/dev/da0p1.eli  bs=1m
 >> 

 VBD> Hello again,

 VBD> I've found the cause of the memory leak and i attach a patch to fix it. I hope
 VBD> the patch is good enough to get committed or at least helps someone made a better
 VBD> patch and commit it. Patched file is src/sys/geom/eli/g_eli.c

 VBD> The problem happens when you're using data integrity verification and you need
 VBD> to write more than MAXPHYS. If you look at g_eli_integrity.c:314 you'll 
 VBD> see that geli creates a second request to write all that's needed.

 VBD> Each of the request get the callback to g_eli_write_done once they're done. The   
 VBD> first request will get up to g_eli.c:209 and find that there are still requests
 VBD> pending so instead of calling g_io_deliver to notify it's written data, it just
 VBD> returns and waits until all requests are done to say everything's OK. The problem
 VBD> is that once you return, you're leaking this g_bio. You can see with vmstat -z how
 VBD> g_bio increases and never releases memory.

 VBD> I just destroy the current bio before returning and that prevents the memory leak.

For me your patch look correct. But the same issue is for read :-). Also, to
avoid the leak I think we can just do g_destroy_bio() before "all sectors"
check. See the attached patch (had some testing).

-- 
Mikolaj Golub

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