Date:   Tue, 29 Jan 2019 17:34:05 +0100
From:   Holger Hoffstätte <holger@...lied-asynchrony.com>
To:     Camelia Alexandra Groza <camelia.groza@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Scott Wood <oss@...error.net>,
        "David S. Miller" <davem@...emloft.net>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Andrew Lunn <andrew@...n.ch>
Subject: Re: [PATCH 4.19 006/103] net: phy: phy driver features are mandatory


On 1/29/19 5:05 PM, Camelia Alexandra Groza wrote:
>> -----Original Message-----
>> From: Holger Hoffstätte <holger@...lied-asynchrony.com>
>> Sent: Tuesday, January 29, 2019 17:50
>> To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>; linux-
>> kernel@...r.kernel.org
>> Cc: stable@...r.kernel.org; Scott Wood <oss@...error.net>; Camelia
>> Alexandra Groza <camelia.groza@....com>; David S. Miller
>> <davem@...emloft.net>; Heiner Kallweit <hkallweit1@...il.com>
>> 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@....com>
>>>
>>> [ 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@...error.net>
>>> Signed-off-by: Camelia Groza <camelia.groza@....com>
>>> Signed-off-by: David S. Miller <davem@...emloft.net>
>>> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
>>> ---
>>>    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.

Applied, unfortunately it doesn't compile since PHY_10GBIT_FEATURES is
nowhere to be found. Took a quick look around and didn't really
find any commit(s) that would apply as well.
Further suggestions welcome. :)

Holger

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