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References: <202307201141.PYWS6ird-lkp@intel.com> <840cdf34-f38e-ab37-623f-9744c3436350@grimberg.me>
In-Reply-To: <840cdf34-f38e-ab37-623f-9744c3436350@grimberg.me>
From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Mon, 24 Jul 2023 10:07:38 -0700
Message-ID: <CAKwvOdnfHeEZcKYJh_VPoMfB5oDa3aAU0CYVt-6TNc3a6Jtc6w@mail.gmail.com>
Subject: Re: drivers/nvme/host/tcp.c:835:12: warning: stack frame size (2256)
 exceeds limit (2048) in 'nvme_tcp_recv_skb'
To:     Sagi Grimberg <sagi@grimberg.me>
Cc:     kernel test robot <lkp@intel.com>,
        Varun Prakash <varun@chelsio.com>, llvm@lists.linux.dev,
        oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org,
        Christoph Hellwig <hch@lst.de>
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On Mon, Jul 24, 2023 at 12:46=E2=80=AFAM Sagi Grimberg <sagi@grimberg.me> w=
rote:
>
>
>
> On 7/20/23 06:10, kernel test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.=
git master
> > head:   bfa3037d828050896ae52f6467b6ca2489ae6fb1
> > commit: c2700d2886a87f83f31e0a301de1d2350b52c79b nvme-tcp: send H2CData=
 PDUs based on MAXH2CDATA
> > date:   1 year, 5 months ago
> > config: riscv-randconfig-r042-20230720 (https://download.01.org/0day-ci=
/archive/20230720/202307201141.PYWS6ird-lkp@intel.com/config)

^ it's from a randconfig...the sanitizers tend to blow up stack usage.

> > compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.gi=
t 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
> > reproduce: (https://download.01.org/0day-ci/archive/20230720/2023072011=
41.PYWS6ird-lkp@intel.com/reproduce)
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new ve=
rsion of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202307201141.PYWS6ird-l=
kp@intel.com/
> >
> > All warnings (new ones prefixed by >>):
> >
> >>> drivers/nvme/host/tcp.c:835:12: warning: stack frame size (2256) exce=
eds limit (2048) in 'nvme_tcp_recv_skb' [-Wframe-larger-than]
> >       835 | static int nvme_tcp_recv_skb(read_descriptor_t *desc, struc=
t sk_buff *skb,
> >           |            ^
> >     1 warning generated.
> >
> >
> > vim +/nvme_tcp_recv_skb +835 drivers/nvme/host/tcp.c
> >
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  834
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03 @835  static int nvme_tcp_recv_=
skb(read_descriptor_t *desc, struct sk_buff *skb,
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  836                           =
    unsigned int offset, size_t len)
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  837  {
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  838          struct nvme_tcp_q=
ueue *queue =3D desc->arg.data;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  839          size_t consumed =
=3D len;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  840          int result;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  841
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  842          while (len) {
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  843                  switch (n=
vme_tcp_recv_state(queue)) {
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  844                  case NVME=
_TCP_RECV_PDU:
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  845                          r=
esult =3D nvme_tcp_recv_pdu(queue, skb, &offset, &len);
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  846                          b=
reak;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  847                  case NVME=
_TCP_RECV_DATA:
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  848                          r=
esult =3D nvme_tcp_recv_data(queue, skb, &offset, &len);
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  849                          b=
reak;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  850                  case NVME=
_TCP_RECV_DDGST:
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  851                          r=
esult =3D nvme_tcp_recv_ddgst(queue, skb, &offset, &len);
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  852                          b=
reak;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  853                  default:
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  854                          r=
esult =3D -EFAULT;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  855                  }
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  856                  if (resul=
t) {
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  857                          d=
ev_err(queue->ctrl->ctrl.device,
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  858                           =
       "receive failed:  %d\n", result);
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  859                          q=
ueue->rd_enabled =3D false;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  860                          n=
vme_tcp_error_recovery(&queue->ctrl->ctrl);
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  861                          r=
eturn result;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  862                  }
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  863          }
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  864
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  865          return consumed;
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  866  }
> > 3f2304f8c6d6ed Sagi Grimberg 2018-12-03  867
> >
> > :::::: The code at line 835 was first introduced by commit
> > :::::: 3f2304f8c6d6ed97849057bd16fee99e434ca796 nvme-tcp: add NVMe over=
 TCP host driver
> >
> > :::::: TO: Sagi Grimberg <sagi@lightbitslabs.com>
> > :::::: CC: Christoph Hellwig <hch@lst.de>
> >
>
> I don't understand how the stack frame size is that big. Looks like a
> wrong complaint?
>


--=20
Thanks,
~Nick Desaulniers