On Sun, Jun 04, 2017 at 10:17:49AM -0700, Florian Fainelli wrote:
> Hi Alex,
>
> On 06/04/2017 01:12 AM, Levin, Alexander (Sasha Levin) wrote:
> > From: Mao Wenan <maowenan@xxxxxxxxxx>
> >
> > [ Upstream commit cafe8df8b9bc9aa3dffa827c1a6757c6cd36f657 ]
> >
> > There is currently no reference count being held on the PHY driver,
> > which makes it possible to remove the PHY driver module while the PHY
> > state machine is running and polling the PHY. This could cause crashes
> > similar to this one to show up:
> >
> > [ 43.361162] BUG: unable to handle kernel NULL pointer dereference at 0000000000000140
> > [ 43.361162] IP: phy_state_machine+0x32/0x490
> > [ 43.361162] PGD 59dc067
> > [ 43.361162] PUD 0
> > [ 43.361162]
> > [ 43.361162] Oops: 0000 [#1] SMP
> > [ 43.361162] Modules linked in: dsa_loop [last unloaded: broadcom]
> > [ 43.361162] CPU: 0 PID: 1299 Comm: kworker/0:3 Not tainted 4.10.0-rc5+ #415
> > [ 43.361162] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> > BIOS Ubuntu-1.8.2-1ubuntu2 04/01/2014
> > [ 43.361162] Workqueue: events_power_efficient phy_state_machine
> > [ 43.361162] task: ffff880006782b80 task.stack: ffffc90000184000
> > [ 43.361162] RIP: 0010:phy_state_machine+0x32/0x490
> > [ 43.361162] RSP: 0018:ffffc90000187e18 EFLAGS: 00000246
> > [ 43.361162] RAX: 0000000000000000 RBX: ffff8800059e53c0 RCX:
> > ffff880006a15c60
> > [ 43.361162] RDX: ffff880006782b80 RSI: 0000000000000000 RDI:
> > ffff8800059e5428
> > [ 43.361162] RBP: ffffc90000187e48 R08: ffff880006a15c40 R09:
> > 0000000000000000
> > [ 43.361162] R10: 0000000000000000 R11: 0000000000000000 R12:
> > ffff8800059e5428
> > [ 43.361162] R13: ffff8800059e5000 R14: 0000000000000000 R15:
> > ffff880006a15c40
> > [ 43.361162] FS: 0000000000000000(0000) GS:ffff880006a00000(0000)
> > knlGS:0000000000000000
> > [ 43.361162] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 43.361162] CR2: 0000000000000140 CR3: 0000000005979000 CR4:
> > 00000000000006f0
> > [ 43.361162] Call Trace:
> > [ 43.361162] process_one_work+0x1b4/0x3e0
> > [ 43.361162] worker_thread+0x43/0x4d0
> > [ 43.361162] ? __schedule+0x17f/0x4e0
> > [ 43.361162] kthread+0xf7/0x130
> > [ 43.361162] ? process_one_work+0x3e0/0x3e0
> > [ 43.361162] ? kthread_create_on_node+0x40/0x40
> > [ 43.361162] ret_from_fork+0x29/0x40
> > [ 43.361162] Code: 56 41 55 41 54 4c 8d 67 68 53 4c 8d af 40 fc ff ff
> > 48 89 fb 4c 89 e7 48 83 ec 08 e8 c9 9d 27 00 48 8b 83 60 ff ff ff 44 8b
> > 73 98 <48> 8b 90 40 01 00 00 44 89 f0 48 85 d2 74 08 4c 89 ef ff d2 8b
> >
> > Keep references on the PHY driver module right before we are going to
> > utilize it in phy_attach_direct(), and conversely when we don't use it
> > anymore in phy_detach().
> >
> > Signed-off-by: Mao Wenan <maowenan@xxxxxxxxxx>
> > [florian: rebase, rework commit message]
> > Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
> > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> >
> > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
>
> This commit alone will cause problems, you will also need to pick this
> one on top of it:
>
> 6d9f66ac7fec2a6ccd649e5909806dfe36f1fc25 ("net: phy: Fix PHY module
> checks and NULL deref in phy_attach_direct()")
Should I also be grabbing a7dac9f9c1
("phy: fix error case of phy_led_triggers_(un)register")?
It says it fixes a commit that's not in -stable, but it looks like it's
still relevant even without that commit.
--
Thanks,
Sasha