Re: [PATCH] net: usb: lan78xx: Use phy_mac_interrupt() for interrupt handling

Daniel Wagner
2019-10-23T07:47:31Z

> > Wouldn't handle_nested_irq() work here instead of the simple thingy?
>
> Daniel could you try this suggestion? Would it work?

[ 6.427289] ------------[ cut here ]------------
[ 6.431977] kernel BUG at drivers/net/phy/mdio_bus.c:626!
[ 6.437453] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[ 6.443013] Modules linked in:
[ 6.446116] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc3-00100-g70cc5ab156c3-dirty #50
[ 6.454763] Hardware name: Raspberry Pi 3 Model B+ (DT)
[ 6.460062] pstate: 00000005 (nzcv daif -PAN -UAO)
[ 6.464928] pc : mdiobus_read+0x68/0x70
[ 6.468821] lr : lan88xx_phy_ack_interrupt+0x1c/0x30
[ 6.473852] sp : ffff800010003d70
[ 6.477208] x29: ffff800010003d70 x28: 0000000000000000
[ 6.482597] x27: 0000000000000001 x26: 0000000000000060
[ 6.487985] x25: 00000000000000e0 x24: ffff8000113ca680
[ 6.493373] x23: ffff0000372ac174 x22: ffff00003768f6d4
[ 6.498762] x21: ffff00003768f600 x20: 0000000000000000
[ 6.504149] x19: ffff0000372c1000 x18: 000000000000000e
[ 6.509537] x17: 0000000000000001 x16: 0000000000000007
[ 6.514923] x15: 000000000000000e x14: 0000000000000013
[ 6.520311] x13: 0000000000000000 x12: 0000000000000000
[ 6.525699] x11: 000000000000057b x10: 0000000000000003
[ 6.531087] x9 : ffff0000383f4750 x8 : ffff0000383f3dc0
[ 6.536474] x7 : ffff0000374be100 x6 : ffff0000383f4750
[ 6.541862] x5 : ffff000037cab700 x4 : 0000000000000008
[ 6.547249] x3 : 0000000000000101 x2 : 000000000000001a
[ 6.552636] x1 : 0000000000000001 x0 : ffff0000372c0800
[ 6.558023] Call trace:
[ 6.560506] mdiobus_read+0x68/0x70
[ 6.564045] phy_interrupt+0x5c/0xb0
[ 6.567672] handle_nested_irq+0xb8/0x130
[ 6.571740] intr_complete+0xb0/0xe0
[ 6.575368] __usb_hcd_giveback_urb+0x58/0xf8
[ 6.579787] usb_giveback_urb_bh+0xac/0x108
[ 6.584032] tasklet_action_common.isra.0+0x154/0x1a0
[ 6.589155] tasklet_hi_action+0x24/0x30
[ 6.593134] __do_softirq+0x120/0x23c
[ 6.596847] irq_exit+0xb8/0xd8
[ 6.600031] __handle_domain_irq+0x64/0xb8
[ 6.604183] bcm2836_arm_irqchip_handle_irq+0x60/0xc0
[ 6.609305] el1_irq+0xb8/0x180
[ 6.612490] arch_cpu_idle+0x10/0x18
[ 6.616115] do_idle+0x200/0x280
[ 6.619387] cpu_startup_entry+0x20/0x40
[ 6.623366] rest_init+0xd4/0xe0
[ 6.626642] arch_call_rest_init+0xc/0x14
[ 6.630706] start_kernel+0x420/0x44c
[ 6.634425] Code: a94153f3 a9425bf5 a8c37bfd d65f03c0 (d4210000)
[ 6.640614] ---[ end trace 97efd7bf12ed0c65 ]---
[ 6.645295] Kernel panic - not syncing: Fatal exception in interrupt
[ 6.651740] SMP: stopping secondary CPUs
[ 6.655719] Kernel Offset: disabled
[ 6.659254] CPU features: 0x0002,24002004
[ 6.663315] Memory Limit: none
[ 6.666416] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

Not really. It turns out phy_interrupt() wants to be run in a threaded
context. As Sebastian says on IRC "but this means, that it was broken from
the beginning"