From fcd03e362b1cd17de487953aac34f2d4574895cf Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Tue, 22 Aug 2017 14:26:47 -0700 Subject: [PATCH] net: phy: Deal with unbound PHY driver in phy_attached_print() Priit reported that stmmac was crashing with the trace below. This is because phy_attached_print() is called too early right after the PHY device has been found, but before it has a driver attached, since that is only done in phy_probe() which occurs later. Fix this by dealing with a possibly NULL phydev->drv point since that can happen here, but could also happen if we voluntarily did an unbind of the PHY device with the PHY driver. sun7i-dwmac 1c50000.ethernet: PTP uses main clock sun7i-dwmac 1c50000.ethernet: no reset control found sun7i-dwmac 1c50000.ethernet: no regulator found sun7i-dwmac 1c50000.ethernet: Ring mode enabled sun7i-dwmac 1c50000.ethernet: DMA HW capability register supported sun7i-dwmac 1c50000.ethernet: Normal descriptors libphy: stmmac: probed Unable to handle kernel NULL pointer dereference at virtual address 00000048 pgd = c0004000 [00000048] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.13.0-rc6-00318-g0065bd7fa384 #1 Hardware name: Allwinner sun7i (A20) Family task: ee868000 task.stack: ee85c000 PC is at phy_attached_print+0x1c/0x8c LR is at stmmac_mdio_register+0x12c/0x200 pc : [] lr : [] psr: 60000013 sp : ee85ddc8 ip : 00000000 fp : c07dfb5c r10: ee981210 r9 : 00000001 r8 : eea73000 r7 : eeaa6dd0 r6 : eeb49800 r5 : 00000000 r4 : 00000000 r3 : 00000000 r2 : 00000000 r1 : 00000000 r0 : eeb49800 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 10c5387d Table: 4000406a DAC: 00000051 Process swapper/0 (pid: 1, stack limit = 0xee85c210) Stack: (0xee85ddc8 to 0xee85e000) ddc0: 00000000 00000002 eeb49400 eea72000 00000000 eeb49400 dde0: c045e6b4 00000000 ffffffff eeab0810 00000000 c08051f8 ee9292c0 c016d480 de00: eea725c0 eea73000 eea72000 00000001 eea726c0 c0457d0c 00000040 00000020 de20: 00000000 c045b850 00000001 00000000 ee981200 eeab0810 eeaa6ed0 ee981210 de40: 00000000 c094a4a0 00000000 c0465180 eeaa7550 f08d0000 c9ffb90c 00000032 de60: fffffffa 00000032 ee981210 ffffffed c0a46620 fffffdfb c0a46620 c03f7be8 de80: ee981210 c0a9a388 00000000 00000000 c0a46620 c03f63e0 ee981210 c0a46620 dea0: ee981244 00000000 00000007 000000c6 c094a4a0 c03f6534 00000000 c0a46620 dec0: c03f6490 c03f49ec ee828a58 ee9217b4 c0a46620 eeaa4b00 c0a43230 c03f59fc dee0: c08051f8 c094a49c c0a46620 c0a46620 00000000 c091c668 c093783c c03f6dfc df00: ffffe000 00000000 c091c668 c010177c eefe0938 eefe0935 c085e200 000000c6 df20: 00000005 c0136bc8 60000013 c080b3a4 00000006 00000006 c07ce7b4 00000000 df40: c07d7ddc c07cef28 eefe0938 eefe093e c0a0b2f0 c0a641c0 c0a641c0 c0a641c0 df60: c0937834 00000007 000000c6 c094a4a0 00000000 c0900d88 00000006 00000006 df80: 00000000 c09005a8 00000000 c060ecf4 00000000 00000000 00000000 00000000 dfa0: 00000000 c060ecfc 00000000 c0107738 00000000 00000000 00000000 00000000 dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffdeffff ffffffff [] (phy_attached_print) from [] (stmmac_mdio_register+0x12c/0x200) [] (stmmac_mdio_register) from [] (stmmac_dvr_probe+0x850/0x96c) [] (stmmac_dvr_probe) from [] (sun7i_gmac_probe+0x120/0x180) [] (sun7i_gmac_probe) from [] (platform_drv_probe+0x50/0xac) [] (platform_drv_probe) from [] (driver_probe_device+0x234/0x2e4) [] (driver_probe_device) from [] (__driver_attach+0xa4/0xa8) [] (__driver_attach) from [] (bus_for_each_dev+0x4c/0x9c) [] (bus_for_each_dev) from [] (bus_add_driver+0x190/0x214) [] (bus_add_driver) from [] (driver_register+0x78/0xf4) [] (driver_register) from [] (do_one_initcall+0x44/0x168) [] (do_one_initcall) from [] (kernel_init_freeable+0x144/0x1d0) [] (kernel_init_freeable) from [] (kernel_init+0x8/0x110) [] (kernel_init) from [] (ret_from_fork+0x14/0x3c) Code: e59021c8 e59d401c e590302c e3540000 (e5922048) ---[ end trace 39ae87c7923562d0 ]--- Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Tested-By: Priit Laes Fixes: fbca164776e4 ("net: stmmac: Use the right logging function in stmmac_mdio_register") Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- drivers/net/phy/phy_device.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 1790f7fec125..2f742ae5b92e 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -864,15 +864,17 @@ EXPORT_SYMBOL(phy_attached_info); #define ATTACHED_FMT "attached PHY driver [%s] (mii_bus:phy_addr=%s, irq=%d)" void phy_attached_print(struct phy_device *phydev, const char *fmt, ...) { + const char *drv_name = phydev->drv ? phydev->drv->name : "unbound"; + if (!fmt) { dev_info(&phydev->mdio.dev, ATTACHED_FMT "\n", - phydev->drv->name, phydev_name(phydev), + drv_name, phydev_name(phydev), phydev->irq); } else { va_list ap; dev_info(&phydev->mdio.dev, ATTACHED_FMT, - phydev->drv->name, phydev_name(phydev), + drv_name, phydev_name(phydev), phydev->irq); va_start(ap, fmt); -- 2.30.2