Messages in this thread |  | | Date | Sun, 25 Sep 2022 07:58:29 +0100 | From | "Russell King (Oracle)" <> | Subject | Re: [PATCH net] net: mvpp2: debugfs: fix problem with previous memory leak fix |
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On Sun, Sep 25, 2022 at 01:27:06AM +0200, Marcin Wojtas wrote: > Hi Russell, > > czw., 22 wrz 2022 o 19:08 Marcin Wojtas <mw@semihalf.com> napisał(a): > > > > Hi, > > > > Thank you both for the patches. > > > > > > czw., 22 wrz 2022 o 18:05 Russell King (Oracle) > > <linux@armlinux.org.uk> napisał(a): > > > > > > On Wed, Sep 21, 2022 at 01:44:44PM +0200, Greg Kroah-Hartman wrote: > > > > In commit fe2c9c61f668 ("net: mvpp2: debugfs: fix memory leak when using > > > > debugfs_lookup()"), if the module is unloaded, the directory will still > > > > be present if the module is loaded again and creating the directory will > > > > fail, causing the creation of additional child debugfs entries for the > > > > individual devices to fail. > > > > > > > > As this module never cleaned up the root directory it created, even when > > > > loaded, and unloading/loading a module is not a normal operation, none > > > > of would normally happen. > > > > > > > > To clean all of this up, use a tiny reference counted structure to hold > > > > the root debugfs directory for the driver, and then clean it up when the > > > > last user of it is removed from the system. This should resolve the > > > > previously reported problems, and the original memory leak that > > > > fe2c9c61f668 ("net: mvpp2: debugfs: fix memory leak when using > > > > debugfs_lookup()") was attempting to fix. > > > > > > For the record... I have a better fix for this, but I haven't been able > > > to get it into a state suitable for submission yet. > > > > > > http://www.home.armlinux.org.uk/~rmk/misc/mvpp2-debugfs.diff > > > > > > Not yet against the net tree. Might have time tomorrow to do that, not > > > sure at the moment. Medical stuff is getting in the way. :( > > > > > > > I'd lean towards this version - it is a bit more compact. I'll try to > > test that tomorrow or during the weekend. > > > > I improved the patch compile and work (tested on my CN913x board). > Feel free to submit (if you wish, I can do it too - please let me know > your preference): > https://github.com/semihalf-wojtas-marcin/Linux-Kernel/commit/0abb75115ffb2772f595bb3346573e27e650018b
I don't see what the compile fixes were in that - it looks like my patch ported onto current -net. Obvious changes:
- moved mvpp2_dbgfs_exit() declaration from after mvpp2_dbgfs_cleanup() to before. - moved definition of mvpp2_root to the top of the file (as no effect on the code.)
and the change to port it:
- dropped my mvpp2_dbgfs_init() hunk (because it's different in -net) - removed static declaration of mvpp2_root in mvpp2_dbgfs_init()
I'm not seeing any other changes.
Note that Sasha has submitted a revert of Greg's original patch for mainline, so my original patch should apply as-is if that revert happens - and I don't see any compile issues with it.
-- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
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