linux-stable.git/drivers/net/phy/phy.c, branch linux-5.4.y

net: phy: Fix race condition on link status change

2022-05-18T07:47:28+00:00

commit 91a7cda1f4b8bdf770000a3b60640576dafe0cec upstream.

This fixes the following error caused by a race condition between
phydev->adjust_link() and a MDIO transaction in the phy interrupt
handler. The issue was reproduced with the ethernet FEC driver and a
micrel KSZ9031 phy.

[  146.195696] fec 2188000.ethernet eth0: MDIO read timeout
[  146.201779] ------------[ cut here ]------------
[  146.206671] WARNING: CPU: 0 PID: 571 at drivers/net/phy/phy.c:942 phy_error+0x24/0x6c
[  146.214744] Modules linked in: bnep imx_vdoa imx_sdma evbug
[  146.220640] CPU: 0 PID: 571 Comm: irq/128-2188000 Not tainted 5.18.0-rc3-00080-gd569e86915b7 #9
[  146.229563] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[  146.236257]  unwind_backtrace from show_stack+0x10/0x14
[  146.241640]  show_stack from dump_stack_lvl+0x58/0x70
[  146.246841]  dump_stack_lvl from __warn+0xb4/0x24c
[  146.251772]  __warn from warn_slowpath_fmt+0x5c/0xd4
[  146.256873]  warn_slowpath_fmt from phy_error+0x24/0x6c
[  146.262249]  phy_error from kszphy_handle_interrupt+0x40/0x48
[  146.268159]  kszphy_handle_interrupt from irq_thread_fn+0x1c/0x78
[  146.274417]  irq_thread_fn from irq_thread+0xf0/0x1dc
[  146.279605]  irq_thread from kthread+0xe4/0x104
[  146.284267]  kthread from ret_from_fork+0x14/0x28
[  146.289164] Exception stack(0xe6fa1fb0 to 0xe6fa1ff8)
[  146.294448] 1fa0:                                     00000000 00000000 00000000 00000000
[  146.302842] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[  146.311281] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[  146.318262] irq event stamp: 12325
[  146.321780] hardirqs last  enabled at (12333): [] __up_console_sem+0x50/0x60
[  146.330013] hardirqs last disabled at (12342): [] __up_console_sem+0x3c/0x60
[  146.338259] softirqs last  enabled at (12324): [] __do_softirq+0x2c0/0x624
[  146.346311] softirqs last disabled at (12319): [] __irq_exit_rcu+0x138/0x178
[  146.354447] ---[ end trace 0000000000000000 ]---

With the FEC driver phydev->adjust_link() calls fec_enet_adjust_link()
calls fec_stop()/fec_restart() and both these function reset and
temporary disable the FEC disrupting any MII transaction that
could be happening at the same time.

fec_enet_adjust_link() and phy_read() can be running at the same time
when we have one additional interrupt before the phy_state_machine() is
able to terminate.

Thread 1 (phylib WQ)       | Thread 2 (phy interrupt)
                           |
                           | phy_interrupt()            <-- PHY IRQ
                           |  handle_interrupt()
                           |   phy_read()
                           |   phy_trigger_machine()
                           |    --> schedule phylib WQ
                           |
                           |
phy_state_machine()        |
 phy_check_link_status()   |
  phy_link_change()        |
   phydev->adjust_link()   |
    fec_enet_adjust_link() |
     --> FEC reset         | phy_interrupt()            <-- PHY IRQ
                           |  phy_read()
                           |

Fix this by acquiring the phydev lock in phy_interrupt().

Link: https://lore.kernel.org/all/20220422152612.GA510015@francesco-nb.int.toradex.com/
Fixes: c974bdbc3e77 ("net: phy: Use threaded IRQ, to allow IRQ from sleeping devices")
cc: 
Signed-off-by: Francesco Dolcini 
Reviewed-by: Andrew Lunn 
Link: https://lore.kernel.org/r/20220506060815.327382-1-francesco.dolcini@toradex.com
Signed-off-by: Jakub Kicinski 
[fd: backport: adapt locking before did_interrupt()/ack_interrupt()
 callbacks removal ]
Signed-off-by: Francesco Dolcini 
Signed-off-by: Greg Kroah-Hartman

phy: phy_start_aneg: Add an unlocked version

2021-11-02T18:46:14+00:00

commit 707293a56f95f8e7e0cfae008010c7933fb68973 upstream.

Split phy_start_aneg into a wrapper which takes the PHY lock, and a
helper doing the real work. This will be needed when
phy_ethtook_ksettings_set takes the lock.

Fixes: 2d55173e71b0 ("phy: add generic function to support ksetting support")
Signed-off-by: Andrew Lunn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

phy: phy_ethtool_ksettings_get: Lock the phy for consistency

2021-11-02T18:46:14+00:00

commit c10a485c3de5ccbf1fff65a382cebcb2730c6b06 upstream.

The PHY structure should be locked while copying information out if
it, otherwise there is no guarantee of self consistency. Without the
lock the PHY state machine could be updating the structure.

Fixes: 2d55173e71b0 ("phy: add generic function to support ksetting support")
Signed-off-by: Andrew Lunn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: phy: fix save wrong speed and duplex problem if autoneg is on

2021-03-17T16:03:41+00:00

[ Upstream commit d9032dba5a2b2bbf0fdce67c8795300ec9923b43 ]

If phy uses generic driver and autoneg is on, enter command
"ethtool -s eth0 speed 50" will not change phy speed actually, but
command "ethtool eth0" shows speed is 50Mb/s because phydev->speed
has been set to 50 and no update later.

And duplex setting has same problem too.

However, if autoneg is on, phy only changes speed and duplex according to
phydev->advertising, but not phydev->speed and phydev->duplex. So in this
case, phydev->speed and phydev->duplex don't need to be set in function
phy_ethtool_ksettings_set() if autoneg is on.

Fixes: 51e2a3846eab ("PHY: Avoid unnecessary aneg restarts")
Signed-off-by: Guangbin Huang 
Signed-off-by: Huazhong Tan 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: phy: Do not warn in phy_stop() on PHY_DOWN

2020-09-26T16:03:15+00:00

[ Upstream commit 5116a8ade333b6c2e180782139c9c516a437b21c ]

When phy_is_started() was added to catch incorrect PHY states,
phy_stop() would not be qualified against PHY_DOWN. It is possible to
reach that state when the PHY driver has been unbound and the network
device is then brought down.

Fixes: 2b3e88ea6528 ("net: phy: improve phy state checking")
Signed-off-by: Florian Fainelli 
Reviewed-by: Andrew Lunn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: phy: fix aneg restart in phy_ethtool_set_eee

2020-05-20T06:20:09+00:00

[ Upstream commit 9de5d235b60a7cdfcdd5461e70c5663e713fde87 ]

phy_restart_aneg() enables aneg in the PHY. That's not what we want
if phydev->autoneg is disabled. In this case still update EEE
advertisement register, but don't enable aneg and don't trigger an
aneg restart.

Fixes: f75abeb8338e ("net: phy: restart phy autonegotiation after EEE advertisment change")
Signed-off-by: Heiner Kallweit 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: phy: avoid clearing PHY interrupts twice in irq handler

2020-03-18T06:17:46+00:00

[ Upstream commit 249bc9744e165abe74ae326f43e9d70bad54c3b7 ]

On all PHY drivers that implement did_interrupt() reading the interrupt
status bits clears them. This means we may loose an interrupt that
is triggered between calling did_interrupt() and phy_clear_interrupt().
As part of the fix make it a requirement that did_interrupt() clears
the interrupt.

The Fixes tag refers to the first commit where the patch applies
cleanly.

Fixes: 49644e68f472 ("net: phy: add callback for custom interrupt handler to struct phy_driver")
Reported-by: Michael Walle 
Signed-off-by: Heiner Kallweit 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: phy: Fix "link partner" information disappear issue

2019-10-16T20:17:01+00:00

Some drivers just call phy_ethtool_ksettings_set() to set the
links, for those phy drivers that use genphy_read_status(), if
autoneg is on, and the link is up, than execute "ethtool -s
ethx autoneg on" will cause "link partner" information disappear.

The call trace is phy_ethtool_ksettings_set()->phy_start_aneg()
->linkmode_zero(phydev->lp_advertising)->genphy_read_status(),
the link didn't change, so genphy_read_status() just return, and
phydev->lp_advertising is zero now.

This patch moves the clear operation of lp_advertising from
phy_start_aneg() to genphy_read_lpa()/genphy_c45_read_lpa(), and
if autoneg on and autoneg not complete, just clear what the
generic functions care about.

Fixes: 88d6272acaaa ("net: phy: avoid unneeded MDIO reads in genphy_read_status")
Signed-off-by: Yonglong Liu 
Reviewed-by: Heiner Kallweit 
Signed-off-by: David S. Miller

net: phy: fix write to mii-ctrl1000 register

2019-10-05T01:11:08+00:00

When userspace writes to the MII_ADVERTISE register, we update phylib's
advertising mask and trigger a renegotiation.  However, writing to the
MII_CTRL1000 register, which contains the gigabit advertisement, does
neither.  This can lead to phylib's copy of the advertisement becoming
de-synced with the values in the PHY register set, which can result in
incorrect negotiation resolution.

Fixes: 5502b218e001 ("net: phy: use phy_resolve_aneg_linkmode in genphy_read_status")
Reviewed-by: Andrew Lunn 
Signed-off-by: Russell King 
Signed-off-by: David S. Miller

net: phy: Do not check Link status when loopback is enabled

2019-09-06T13:11:21+00:00

While running stmmac selftests I found that in my 1G setup some tests
were failling when running with PHY loopback enabled.

It looks like when loopback is enabled the PHY will report that Link is
down even though there is a valid connection.

As in loopback mode the data will not be sent anywhere we can bypass the
logic of checking if Link is valid thus saving unecessary reads.

Signed-off-by: Jose Abreu 
Signed-off-by: David S. Miller