linux-kernel - Re: [regression v6.5-rc1] PCI: comm "swapper/0" leaking memory

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Message-ID: <CAG7k0Ep6ZT6f_wcr67ZOz-kDjNx2M-wax8QFoA5-WfyMhycR3A@mail.gmail.com>
Date:   Wed, 6 Sep 2023 12:03:20 +0100
From:   Ross Lagerwall <ross.lagerwall@...ud.com>
To:     Kalle Valo <kvalo@...nel.org>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, ath11k@...ts.infradead.org,
        regressions@...ts.linux.dev
Subject: Re: [regression v6.5-rc1] PCI: comm "swapper/0" leaking memory

On Wed, Sep 6, 2023 at 9:40 AM Kalle Valo <kvalo@...nel.org> wrote:
>
> Ross Lagerwall <ross.lagerwall@...ud.com> writes:
>
> > On Wed, Aug 30, 2023 at 10:21 AM Kalle Valo <kvalo@...nel.org> wrote:
> >
> >>
> >> I noticed that starting from v6.5-rc1 my ath11k tests reported several
> >> memory leaks from swapper/0:
> >>
> >> unreferenced object 0xffff88810a02b7a8 (size 96):
> >>   comm "swapper/0", pid 1, jiffies 4294671838 (age 98.120s)
> >>   hex dump (first 32 bytes):
> >>     80 b8 02 0a 81 88 ff ff b8 72 07 00 00 c9 ff ff  .........r......
> >>     c8 b7 02 0a 81 88 ff ff 00 00 00 00 00 00 00 00  ................
> >>   backtrace:
> >> unreferenced object 0xffff88810a02b880 (size 96):
> >>   comm "swapper/0", pid 1, jiffies 4294671838 (age 98.120s)
> >>   hex dump (first 32 bytes):
> >>     58 b9 02 0a 81 88 ff ff a8 b7 02 0a 81 88 ff ff  X...............
> >>     a0 b8 02 0a 81 88 ff ff 00 00 00 00 00 00 00 00  ................
> >>   backtrace:
> >> unreferenced object 0xffff88810a02b958 (size 96):
> >>   comm "swapper/0", pid 1, jiffies 4294671838 (age 98.120s)
> >>   hex dump (first 32 bytes):
> >>     30 ba 02 0a 81 88 ff ff 80 b8 02 0a 81 88 ff ff  0...............
> >>     78 b9 02 0a 81 88 ff ff 00 00 00 00 00 00 00 00  x...............
> >>   backtrace:
> >> unreferenced object 0xffff88810a02ba30 (size 96):
> >>   comm "swapper/0", pid 1, jiffies 4294671838 (age 98.120s)
> >>   hex dump (first 32 bytes):
> >>     08 bb 02 0a 81 88 ff ff 58 b9 02 0a 81 88 ff ff  ........X.......
> >>     50 ba 02 0a 81 88 ff ff 00 00 00 00 00 00 00 00  P...............
> >>   backtrace:
> >> unreferenced object 0xffff88810a02bb08 (size 96):
> >>   comm "swapper/0", pid 1, jiffies 4294671838 (age 98.120s)
> >>   hex dump (first 32 bytes):
> >>     e0 bb 02 0a 81 88 ff ff 30 ba 02 0a 81 88 ff ff  ........0.......
> >>     28 bb 02 0a 81 88 ff ff 00 00 00 00 00 00 00 00  (...............
> >>   backtrace:
> >>
> >> I can easily reproduce this by doing a simple insmod and rmmod of ath11k
> >> and it's dependencies (mac80211, MHI etc). I can reliability reproduce
> >> the leaks but I only see them once after a boot, I need to reboot the
> >> host to see the leaks again. v6.4 has no leaks.
> >>
> >> I did a bisect and found the commit below. I verified reverting the
> >> commit makes the leaks go away.
> >>
> >> commit e54223275ba1bc6f704a6bab015fcd2ae4f72572
> >> Author:     Ross Lagerwall <ross.lagerwall@...rix.com>
> >> AuthorDate: Thu May 25 16:32:48 2023 +0100
> >> Commit:     Bjorn Helgaas <bhelgaas@...gle.com>
> >> CommitDate: Fri Jun 9 15:06:16 2023 -0500
> >>
> >>     PCI: Release resource invalidated by coalescing
> >
> > Hi Kalle,
> >
> > I can't reproduce the leak by loading/unloading the ath11k module. I suspect
> > that the leak is always there when PCI resources are coalesced but
> > kmemleak doesn't notice until ath11k is loaded.
> >
> > Can you please try the following to confirm it fixes it?
>
> I run various tests with your patch and I don't see leaks anymore. I
> also veried that without your patch I see the leak immediately.
>
> Thanks for fixing this so quickly, it would good to have this fix in
> v6.6 if possible.
>
> Tested-by: Kalle Valo <kvalo@...nel.org>
>

Thanks, I will send out a proper patch now.

Ross