Re: [PATCH v5] remoteproc: Fix NULL pointer dereference in rproc_virtio_notify

From: Mathieu Poirier
Date: Mon Mar 16 2020 - 12:55:40 EST

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On Wed, 11 Mar 2020 at 14:01, Bjorn Andersson
<bjorn.andersson@xxxxxxxxxx> wrote:
>
> On Tue 10 Mar 06:19 PDT 2020, Arnaud POULIQUEN wrote:
>
> >
> >
> > > -----Original Message-----
> > > From: linux-remoteproc-owner@xxxxxxxxxxxxxxx <linux-remoteproc-
> > > owner@xxxxxxxxxxxxxxx> On Behalf Of Nikita Shubin
> > > Sent: mardi 10 mars 2020 13:09
> > > To: Arnaud POULIQUEN <arnaud.pouliquen@xxxxxx>
> > > Cc: stable@xxxxxxxxxxxxxxx; Ohad Ben-Cohen <ohad@xxxxxxxxxx>; Bjorn
> > > Andersson <bjorn.andersson@xxxxxxxxxx>; linux-
> > > remoteproc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Mathieu Poirier
> > > <mathieu.poirier@xxxxxxxxxx>
> > > Subject: Re: [PATCH v5] remoteproc: Fix NULL pointer dereference in
> > > rproc_virtio_notify
> > >
> > > On Mon, Mar 09, 2020 at 03:22:24PM +0100, Arnaud POULIQUEN wrote:
> > > > Hi,
> > > >
> > > > sorry for the late answer...
> > > >
> > > > On 3/6/20 8:24 AM, Nikita Shubin wrote:
> > > > > Undefined rproc_ops .kick method in remoteproc driver will result in
> > > > > "Unable to handle kernel NULL pointer dereference" in
> > > > > rproc_virtio_notify, after firmware loading if:
> > > > >
> > > > > 1) .kick method wasn't defined in driver
> > > > > 2) resource_table exists in firmware and has "Virtio device entry"
> > > > > defined
> > > > >
> > > > > Let's refuse to register an rproc-induced virtio device if no kick
> > > > > method was defined for rproc.
> > > > >
> > > > > [ 13.180049][ T415] 8<--- cut here ---
> > > > > [ 13.190558][ T415] Unable to handle kernel NULL pointer dereference
> > > at virtual address 00000000
> > > > > [ 13.212544][ T415] pgd = (ptrval)
> > > > > [ 13.217052][ T415] [00000000] *pgd=00000000
> > > > > [ 13.224692][ T415] Internal error: Oops: 80000005 [#1] PREEMPT SMP
> > > ARM
> > > > > [ 13.231318][ T415] Modules linked in: rpmsg_char imx_rproc
> > > virtio_rpmsg_bus rpmsg_core [last unloaded: imx_rproc]
> > > > > [ 13.241687][ T415] CPU: 0 PID: 415 Comm: unload-load.sh Not tainted
> > > 5.5.2-00002-g707df13bbbdd #6
> > > > > [ 13.250561][ T415] Hardware name: Freescale i.MX7 Dual (Device Tree)
> > > > > [ 13.257009][ T415] PC is at 0x0
> > > > > [ 13.260249][ T415] LR is at rproc_virtio_notify+0x2c/0x54
> > > > > [ 13.265738][ T415] pc : [<00000000>] lr : [<8050f6b0>] psr: 60010113
> > > > > [ 13.272702][ T415] sp : b8d47c48 ip : 00000001 fp : bc04de00
> > > > > [ 13.278625][ T415] r10: bc04c000 r9 : 00000cc0 r8 : b8d46000
> > > > > [ 13.284548][ T415] r7 : 00000000 r6 : b898f200 r5 : 00000000 r4 :
> > > b8a29800
> > > > > [ 13.291773][ T415] r3 : 00000000 r2 : 990a3ad4 r1 : 00000000 r0 :
> > > b8a29800
> > > > > [ 13.299000][ T415] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA
> > > ARM Segment none
> > > > > [ 13.306833][ T415] Control: 10c5387d Table: b8b4806a DAC: 00000051
> > > > > [ 13.313278][ T415] Process unload-load.sh (pid: 415, stack limit =
> > > 0x(ptrval))
> > > > > [ 13.320591][ T415] Stack: (0xb8d47c48 to 0xb8d48000)
> > > > > [ 13.325651][ T415] 7c40: b895b680 00000001 b898f200 803c6430
> > > b895bc80 7f00ae18
> > > > > [ 13.334531][ T415] 7c60: 00000035 00000000 00000000 b9393200
> > > 80b3ed80 00004000 b9393268 bbf5a9a2
> > > > > [ 13.343410][ T415] 7c80: 00000e00 00000200 00000000 7f00aff0 7f00a014
> > > b895b680 b895b800 990a3ad4
> > > > > [ 13.352290][ T415] 7ca0: 00000001 b898f210 b898f200 00000000
> > > 00000000 7f00e000 00000001 00000000
> > > > > [ 13.361170][ T415] 7cc0: 00000000 803c62e0 80b2169c 802a0924
> > > b898f210 00000000 00000000 b898f210
> > > > > [ 13.370049][ T415] 7ce0: 80b9ba44 00000000 80b9ba48 00000000
> > > 7f00e000 00000008 80b2169c 80400114
> > > > > [ 13.378929][ T415] 7d00: 80b2169c 8061fd64 b898f210 7f00e000
> > > 80400744 b8d46000 80b21634 80b21634
> > > > > [ 13.387809][ T415] 7d20: 80b2169c 80400614 80b21634 80400718
> > > 7f00e000 00000000 b8d47d7c 80400744
> > > > > [ 13.396689][ T415] 7d40: b8d46000 80b21634 80b21634 803fe338
> > > b898f254 b80fe76c b8d32e38 990a3ad4
> > > > > [ 13.405569][ T415] 7d60: fffffff3 b898f210 b8d46000 00000001 b898f254
> > > 803ffe7c 80857a90 b898f210
> > > > > [ 13.414449][ T415] 7d80: 00000001 990a3ad4 b8d46000 b898f210
> > > b898f210 80b17aec b8a29c20 803ff0a4
> > > > > [ 13.423328][ T415] 7da0: b898f210 00000000 b8d46000 803fb8e0
> > > b898f200 00000000 80b17aec b898f210
> > > > > [ 13.432209][ T415] 7dc0: b8a29c20 990a3ad4 b895b900 b898f200
> > > 8050fb7c 80b17aec b898f210 b8a29c20
> > > > > [ 13.441088][ T415] 7de0: b8a29800 b895b900 b8a29a04 803c5ec0
> > > b8a29c00 b898f200 b8a29a20 00000007
> > > > > [ 13.449968][ T415] 7e00: b8a29c20 8050fd78 b8a29800 00000000
> > > b8a29a20 b8a29c04 b8a29820 b8a299d0
> > > > > [ 13.458848][ T415] 7e20: b895b900 8050e5a4 b8a29800 b8a299d8
> > > b8d46000 b8a299e0 b8a29820 b8a299d0
> > > > > [ 13.467728][ T415] 7e40: b895b900 8050e008 000041ed 00000000
> > > b8b8c440 b8a299d8 b8a299e0 b8a299d8
> > > > > [ 13.476608][ T415] 7e60: b8b8c440 990a3ad4 00000000 b8a29820
> > > b8b8c400 00000006 b8a29800 b895b880
> > > > > [ 13.485487][ T415] 7e80: b8d47f78 00000000 00000000 8050f4b4
> > > 00000006 b895b890 b8b8c400 008fbea0
> > > > > [ 13.494367][ T415] 7ea0: b895b880 8029f530 00000000 00000000
> > > b8d46000 00000006 b8d46000 008fbea0
> > > > > [ 13.503246][ T415] 7ec0: 8029f434 00000000 b8d46000 00000000
> > > 00000000 8021e2e4 0000000a 8061fd0c
> > > > > [ 13.512125][ T415] 7ee0: 0000000a b8af0c00 0000000a b8af0c40
> > > 00000001 b8af0c40 00000000 8061f910
> > > > > [ 13.521005][ T415] 7f00: 0000000a 80240af4 00000002 b8d46000
> > > 00000000 8061fd0c 00000002 80232d7c
> > > > > [ 13.529884][ T415] 7f20: 00000000 b8d46000 00000000 990a3ad4
> > > 00000000 00000006 b8a62d80 008fbea0
> > > > > [ 13.538764][ T415] 7f40: b8d47f78 00000000 b8d46000 00000000
> > > 00000000 802210c0 b88f2900 00000000
> > > > > [ 13.547644][ T415] 7f60: b8a62d80 b8a62d80 b8d46000 00000006
> > > 008fbea0 80221320 00000000 00000000
> > > > > [ 13.556524][ T415] 7f80: b8af0c00 990a3ad4 0000006c 008fbea0 76f1cda0
> > > 00000004 80101204 00000004
> > > > > [ 13.565403][ T415] 7fa0: 00000000 80101000 0000006c 008fbea0
> > > 00000001 008fbea0 00000006 00000000
> > > > > [ 13.574283][ T415] 7fc0: 0000006c 008fbea0 76f1cda0 00000004 00000006
> > > 00000006 00000000 00000000
> > > > > [ 13.583162][ T415] 7fe0: 00000004 7ebaf7d0 76eb4c0b 76e3f206
> > > 600d0030 00000001 00000000 00000000
> > > > > [ 13.592056][ T415] [<8050f6b0>] (rproc_virtio_notify) from
> > > [<803c6430>] (virtqueue_notify+0x1c/0x34)
> > > > > [ 13.601298][ T415] [<803c6430>] (virtqueue_notify) from [<7f00ae18>]
> > > (rpmsg_probe+0x280/0x380 [virtio_rpmsg_bus])
> > > > > [ 13.611663][ T415] [<7f00ae18>] (rpmsg_probe [virtio_rpmsg_bus])
> > > from [<803c62e0>] (virtio_dev_probe+0x1f8/0x2c4)
> > > > > [ 13.622022][ T415] [<803c62e0>] (virtio_dev_probe) from [<80400114>]
> > > (really_probe+0x200/0x450)
> > > > > [ 13.630817][ T415] [<80400114>] (really_probe) from [<80400614>]
> > > (driver_probe_device+0x16c/0x1ac)
> > > > > [ 13.639873][ T415] [<80400614>] (driver_probe_device) from
> > > [<803fe338>] (bus_for_each_drv+0x84/0xc8)
> > > > > [ 13.649102][ T415] [<803fe338>] (bus_for_each_drv) from [<803ffe7c>]
> > > (__device_attach+0xd4/0x164)
> > > > > [ 13.658069][ T415] [<803ffe7c>] (__device_attach) from [<803ff0a4>]
> > > (bus_probe_device+0x84/0x8c)
> > > > > [ 13.666950][ T415] [<803ff0a4>] (bus_probe_device) from
> > > [<803fb8e0>] (device_add+0x444/0x768)
> > > > > [ 13.675572][ T415] [<803fb8e0>] (device_add) from [<803c5ec0>]
> > > (register_virtio_device+0xa4/0xfc)
> > > > > [ 13.684541][ T415] [<803c5ec0>] (register_virtio_device) from
> > > [<8050fd78>] (rproc_add_virtio_dev+0xcc/0x1b8)
> > > > > [ 13.694466][ T415] [<8050fd78>] (rproc_add_virtio_dev) from
> > > [<8050e5a4>] (rproc_start+0x148/0x200)
> > > > > [ 13.703521][ T415] [<8050e5a4>] (rproc_start) from [<8050e008>]
> > > (rproc_boot+0x384/0x5c0)
> > > > > [ 13.711708][ T415] [<8050e008>] (rproc_boot) from [<8050f4b4>]
> > > (state_store+0x3c/0xc8)
> > > > > [ 13.719723][ T415] [<8050f4b4>] (state_store) from [<8029f530>]
> > > (kernfs_fop_write+0xfc/0x214)
> > > > > [ 13.728348][ T415] [<8029f530>] (kernfs_fop_write) from [<8021e2e4>]
> > > (__vfs_write+0x30/0x1cc)
> > > > > [ 13.736971][ T415] [<8021e2e4>] (__vfs_write) from [<802210c0>]
> > > (vfs_write+0xac/0x17c)
> > > > > [ 13.744985][ T415] [<802210c0>] (vfs_write) from [<80221320>]
> > > (ksys_write+0x64/0xe4)
> > > > > [ 13.752825][ T415] [<80221320>] (ksys_write) from [<80101000>]
> > > (ret_fast_syscall+0x0/0x54)
> > > > > [ 13.761178][ T415] Exception stack(0xb8d47fa8 to 0xb8d47ff0)
> > > > > [ 13.766932][ T415] 7fa0: 0000006c 008fbea0 00000001 008fbea0
> > > 00000006 00000000
> > > > > [ 13.775811][ T415] 7fc0: 0000006c 008fbea0 76f1cda0 00000004 00000006
> > > 00000006 00000000 00000000
> > > > > [ 13.784687][ T415] 7fe0: 00000004 7ebaf7d0 76eb4c0b 76e3f206
> > > > > [ 13.790442][ T415] Code: bad PC value
> > > > > [ 13.839214][ T415] ---[ end trace 1fe21ecfc9f28852 ]---
> > > > >
> > > > > Signed-off-by: Nikita Shubin <NShubin@xxxxxxxxxx>
> > > > > Fixes: 7a186941626d ("remoteproc: remove the single rpmsg vdev
> > > > > limitation")
> > > > > Cc: stable@xxxxxxxxxxxxxxx
> > > > > ---
> > > > > drivers/remoteproc/remoteproc_virtio.c | 7 +++++++
> > > > > 1 file changed, 7 insertions(+)
> > > > >
> > > > > diff --git a/drivers/remoteproc/remoteproc_virtio.c
> > > > > b/drivers/remoteproc/remoteproc_virtio.c
> > > > > index 8c07cb2ca8ba..31a62a0b470e 100644
> > > > > --- a/drivers/remoteproc/remoteproc_virtio.c
> > > > > +++ b/drivers/remoteproc/remoteproc_virtio.c
> > > > > @@ -334,6 +334,13 @@ int rproc_add_virtio_dev(struct rproc_vdev
> > > *rvdev, int id)
> > > > > struct rproc_mem_entry *mem;
> > > > > int ret;
> > > > >
> > > > > + if (rproc->ops->kick == NULL) {
> > > > > + ret = -EINVAL;
> > > > > + dev_err(dev, ".kick method not defined for %s",
> > > > > + rproc->name);
> > > > > + goto out;
> > > > > + }
> > > > > +
> > > > Should the kick ops be mandatory for all the platforms? How about making
> > > it optional instead?
> > >
> > > Hi, Arnaud.
> > >
> > > It is not mandatory, currently it must be provided if specified vdev entry is in
> > > resourse table. Otherwise it looks like there is no point in creating vdev.
> >
> > Yes, my question was about having it optional for vdev also. A platform could implement the vdev
> > without kick mechanism but by polling depending due to hardware capability...
> > This could be an alternative avoiding to implement a dummy function in platform driver.
> >

Arnaud has a point. It _could_ be possible to have a platform that
works by polling and in such a case a dummy kick function would be
required, but that would likely entail more changes to the remoteproc
core. Since we haven't seen the need to support such a scenario and
don't have the full picture of what it would take to do so, I suggest
to move forward with Nikita's approach and revise later on if there is
a need.

Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>

>
> Is this a real thing or a theoretical suggestion?
>
> Regards,
> Bjorn
>
> > Anyway it just a proposal that makes sense from MPOV. If Bjorn is ok with your patch, nothing blocking on my side.
> >
> > Regards
> > Arnaud
> >
> > >
> > >
> > > >
> > > > Regards,
> > > > Arnaud
> > > >
> > > > > /* Try to find dedicated vdev buffer carveout */
> > > > > mem = rproc_find_carveout_by_name(rproc, "vdev%dbuffer",
> > > rvdev->index);
> > > > > if (mem) {
> > > > >

Next message: Neil Armstrong: "Re: [PATCH] arm64: dts: meson-g12-common: add spicc controller nodes"
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Next in thread: Arnaud POULIQUEN: "Re: [PATCH v5] remoteproc: Fix NULL pointer dereference in rproc_virtio_notify"
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