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

From: Holger HoffstÃtte
Date: Tue Jan 29 2019 - 10:58:58 EST


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