On Fri, Dec 14, 2007 at 01:48:23PM -0800, Greg KH wrote: > On Mon, Dec 03, 2007 at 01:25:51PM -0800, Greg KH wrote: > > On Tue, Dec 04, 2007 at 12:09:59AM +0300, Alexey Dobriyan wrote: > > > On Mon, Dec 03, 2007 at 12:47:16PM -0800, Greg KH wrote: > > > > On Mon, Dec 03, 2007 at 12:26:07PM +0300, Alexey Dobriyan wrote: > > > > > Hi, Greg! > > > > > > > > > > Commit ce2c9cb0259acd2aed184499ebe41ab00da13b25 aka > > > > > "kobject: remove the static array for the name" introduced memory leak > > > > > of a module name after modprobe/rmmod. Apparently for modules > > > > > ->release > > > > > callback is NULL. > > > > > > > > > > kobject_cleanup: ->release = 00000000, name = 'foo_sysctl' > > > > > Pid: 1927, comm: rmmod Not tainted > > > > > 2.6.24-rc3-e1cca7e8d484390169777b423a7fe46c7021fec1 #5 > > > > > [<c10d4a58>] kobject_cleanup+0xb8/0xc0 > > > > > [<c10d4a60>] kobject_release+0x0/0x10 > > > > > [<c10d587b>] kref_put+0x2b/0xa0 > > > > > [<c11dbe85>] _spin_unlock+0x25/0x40 > > > > > [<c1045b78>] free_module+0x78/0xd0 > > > > > [<c104773f>] sys_delete_module+0x12f/0x1a0 > > > > > > > > Hm, _which_ kobject associated with a module, there are 3 of them I > > > > think :) > > > > > > Ouch! > > > > > > > They should all have a release function, and if they do not, we think > > > > it's a "static" kobject and it is not safe to free that name. > > > > > > > > I've been working on cleaning this up a lot in the -mm tree with over 80 > > > > patches for the kset/kobject apis and interfaces. > > > > > > > > But if we have a dynamic kobject, and we aren't freeing it properly, > > > > please let me know which one it is and I'll work to fix it for 2.6.24. > > > > > > The one which is passed to kobject_set_name() in mod_sysfs_init().. > > > > That one should be set to the module_ktype, which is in kernel/params.c, > > so the release function there should... oh crap, there is no release > > function. That's a bug. After I get out of meetings tonight I'll write > > up a patch for that, unless someone beats me to it :) > > Ok, this is a mess. We can't really have a release function for this > kobject, as the structure it is embedded it has it's own memory > management issues. > > To fix this properly is going to take some major kobject/module surgery, > it's not a simple fix at all. I'll tackle it for 2.6.25, as it fits in > nicely with the other kobject rework that I've already done in the -mm > tree. > > So, for now, can we just live with this tiny memory leak on module > unload?
For the record, this leak screws any testing one can do wrt module unload races. You can't really leave box overnight running modprobe/rmmod in a loop, because OOM killer will finally kick in. Hey, this is exactly how it was noticed at all. > Or is the above trace something that users will see when unloading > modules? No, it's added debugging. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
