RE: [PATCH 4.19 006/103] net: phy: phy driver features are mandatory

[Camelia Alexandra Groza]

> -----Original Message-----
> From: Holger HoffstÃtte <holger@xxxxxxxxxxxxxxxxxxxxxx>
> Sent: Tuesday, January 29, 2019 17:50
> To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; linux-
> kernel@xxxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxxxxxxx; Scott Wood <oss@xxxxxxxxxxxx>; Camelia
> Alexandra Groza <camelia.groza@xxxxxxx>; David S. Miller
> <davem@xxxxxxxxxxxxx>; Heiner Kallweit <hkallweit1@xxxxxxxxx>
> Subject: Re: [PATCH 4.19 006/103] net: phy: phy driver features are
> mandatory
> 
> On 1/29/19 12:34 PM, Greg Kroah-Hartman wrote:
> > 4.19-stable review patch.  If anyone has any objections, please let me
> know.
> >
> > ------------------
> >
> > From: Camelia Groza <camelia.groza@xxxxxxx>
> >
> > [ Upstream commit 3e64cf7a435ed0500e3adaa8aada2272d3ae8abc ]
> >
> > Since phy driver features became a link_mode bitmap, phy drivers that
> > don't have a list of features configured will cause the kernel to crash
> > when probed.
> >
> > Prevent the phy driver from registering if the features field is missing.
> >
> > Fixes: 719655a14971 ("net: phy: Replace phy driver features u32 with
> link_mode bitmap")
> > Reported-by: Scott Wood <oss@xxxxxxxxxxxx>
> > Signed-off-by: Camelia Groza <camelia.groza@xxxxxxx>
> > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > ---
> >   drivers/net/phy/phy_device.c |    5 +++++
> >   include/linux/phy.h          |    4 ++--
> >   2 files changed, 7 insertions(+), 2 deletions(-)
> >
> > --- a/drivers/net/phy/phy_device.c
> > +++ b/drivers/net/phy/phy_device.c
> > @@ -1917,6 +1917,11 @@ int phy_driver_register(struct phy_drive
> >   {
> >   	int retval;
> >
> > +	if (WARN_ON(!new_driver->features)) {
> > +		pr_err("%s: Driver features are missing\n", new_driver-
> >name);
> > +		return -EINVAL;
> > +	}
> > +
> >   	new_driver->mdiodrv.flags |= MDIO_DEVICE_IS_PHY;
> >   	new_driver->mdiodrv.driver.name = new_driver->name;
> >   	new_driver->mdiodrv.driver.bus = &mdio_bus_type;
> > --- a/include/linux/phy.h
> > +++ b/include/linux/phy.h
> > @@ -491,8 +491,8 @@ struct phy_device {
> >    *   only works for PHYs with IDs which match this field
> >    * name: The friendly name of this PHY type
> >    * phy_id_mask: Defines the important bits of the phy_id
> > - * features: A list of features (speed, duplex, etc) supported
> > - *   by this PHY
> > + * features: A mandatory list of features (speed, duplex, etc)
> > + *   supported by this PHY
> >    * flags: A bitfield defining certain other features this PHY
> >    *   supports (like interrupts)
> >    *
> >
> 
> This patch leads to the following dump during boot and no working
> network:
> 
> Jan 29 13:11:50 ragnarok kernel: RIP: 0010:phy_driver_register+0x5f/0x80
> [libphy]
> Jan 29 13:11:50 ragnarok kernel: Code: dd 06 a0 48 c7 47 40 30 e4 06 a0 48 89
> 77 10 c7 47 24 02 00 00 00 e8 10 5c 44 e1 89 c5 85 c0 0f 85 aa 1d 00 00 89 e8 5b
> 5d c3 <0f> 0b 48 c7 c7 f0 20 07 a0 48 89 c6 bd ea ff ff ff e8 c9 4c 02 e1
> Jan 29 13:11:50 ragnarok kernel: RSP: 0018:ffffc90000df3c78 EFLAGS:
> 00010246
> Jan 29 13:11:50 ragnarok kernel: RAX: ffffffffa0071c8d RBX: 0000000000000000
> RCX: 0000000000000000
> Jan 29 13:11:50 ragnarok kernel: RDX: 0000000000000000 RSI: ffffffffa0076900
> RDI: ffffffffa0076040
> Jan 29 13:11:50 ragnarok kernel: RBP: ffffffffa007a000 R08: 0000000000000044
> R09: 0000000000000228
> Jan 29 13:11:50 ragnarok kernel: R10: ffff888603a0d6f8 R11:
> 000000000000003c R12: ffff888601252d00
> Jan 29 13:11:50 ragnarok kernel: R13: 0000000000000002 R14:
> ffffc90000df3e98 R15: ffffffffa0076900
> Jan 29 13:11:50 ragnarok kernel: FS:  00007feea9ced800(0000)
> GS:ffff888607240000(0000) knlGS:0000000000000000
> Jan 29 13:11:50 ragnarok kernel: CS:  0010 DS: 0000 ES: 0000 CR0:
> 0000000080050033
> Jan 29 13:11:50 ragnarok kernel: CR2: 00007feea9cdfc42 CR3:
> 00000005fec64001 CR4: 00000000000606e0
> Jan 29 13:11:50 ragnarok kernel: Call Trace:
> Jan 29 13:11:50 ragnarok kernel:  ? 0xffffffffa007a000
> Jan 29 13:11:50 ragnarok kernel:  phy_init+0x24/0x58 [libphy]
> Jan 29 13:11:50 ragnarok kernel:  do_one_initcall+0x43/0x1af
> Jan 29 13:11:50 ragnarok kernel:  ? _cond_resched+0x15/0x30
> Jan 29 13:11:50 ragnarok kernel:  ? kmem_cache_alloc_trace+0x154/0x1b0
> Jan 29 13:11:50 ragnarok kernel:  do_init_module+0x5a/0x210
> Jan 29 13:11:50 ragnarok kernel:  load_module+0x203a/0x2500
> Jan 29 13:11:50 ragnarok kernel:  ? vfs_read+0x10d/0x130
> Jan 29 13:11:50 ragnarok kernel:  ? __se_sys_finit_module+0xb1/0xd0
> Jan 29 13:11:50 ragnarok kernel:  __se_sys_finit_module+0xb1/0xd0
> Jan 29 13:11:50 ragnarok kernel:  do_syscall_64+0x3e/0xe0
> Jan 29 13:11:50 ragnarok kernel:
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> Jan 29 13:11:50 ragnarok kernel: RIP: 0033:0x7feeaa2417c9
> Jan 29 13:11:50 ragnarok kernel: Code: 00 00 00 75 05 48 83 c4 18 c3 e8 82 9c 01
> 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05
> <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 87 c6 0c 00 f7 d8 64 89 01 48
> Jan 29 13:11:50 ragnarok kernel: RSP: 002b:00007fff6fa6ea08 EFLAGS:
> 00000246 ORIG_RAX: 0000000000000139
> Jan 29 13:11:50 ragnarok kernel: RAX: ffffffffffffffda RBX: 000055c6eac06db0
> RCX: 00007feeaa2417c9
> Jan 29 13:11:50 ragnarok kernel: RDX: 0000000000000000 RSI:
> 00007feeaa4198fd RDI: 0000000000000006
> Jan 29 13:11:50 ragnarok kernel: RBP: 00007feeaa4198fd R08:
> 0000000000000000 R09: 000055c6eac03000
> Jan 29 13:11:50 ragnarok kernel: R10: 0000000000000006 R11:
> 0000000000000246 R12: 0000000000000000
> Jan 29 13:11:50 ragnarok kernel: R13: 000055c6eabfc1d0 R14:
> 0000000000020000 R15: 000055c6eac06db0
> Jan 29 13:11:50 ragnarok kernel: ---[ end trace 18e05a0afeb140b2 ]---
> Jan 29 13:11:50 ragnarok kernel: libphy: Generic 10G PHY: Driver features are
> missing
> 
> Apparently the r8169 driver for my NIC does something wrong wrt. this
> fix and the original commit (719655a14971), but regardless - reverting this
> patch leads to a booting & working 4.19.19:
> 
> Jan 29 13:29:16 ragnarok kernel: libphy: r8169: probed
> Jan 29 13:29:19 ragnarok kernel: RTL8211E Gigabit Ethernet r8169-400:00:
> attached PHY driver [RTL8211E Gigabit Ethernet] (mii_bus:phy_addr=r8169-
> 400:00, irq=IGNORE)
> 
> I've cc'ed Heiner Kallweit who might know why phylib with this fix and r8169
> don't like each other.
> 
> cheers,
> Holger

Hi

This points to an issue with the Generic 10G PHY driver. The following patch seems to be missing from the 4.19 stable tree and should be merged:
f802912 net: phy: genphy_10g_driver: Avoid NULL pointer dereference

Thanks for pointing this out.

Regards,
Camelia