From mboxrd@z Thu Jan 1 00:00:00 1970 From: ml@communistcode.co.uk (Jack Mitchell) Date: Mon, 04 Feb 2013 11:36:36 +0000 Subject: [BUG] kernel oops in pin_request Message-ID: <510F9D44.2000700@communistcode.co.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org I am developing a driver located at [1]. The driver has two devices on a single SPI bus. When the devices are probed the pins for the SPI bus get requested twice, as so: pinctrl = devm_pinctrl_get_select_default(&spi->dev); if (IS_ERR(pinctrl)) { pr_debug("%s: Setting pins failed: %d\n", __func__, (s32) pinctrl); } The driver is DT only, and as such gets it's pins and setup from the DT [2]. When the second request happens I get the following output the kernel log: Jan 25 15:04:54 beaglebone user.err kernel: [ 67.319188] pinctrl-single 44e10800.pinmux: pin 44e1099c already requested by 48030000.spi; cannot claim for spi2.1 Jan 25 15:04:54 beaglebone user.err kernel: [ 67.330496] pinctrl-single 44e10800.pinmux: pin-103 (spi2.1) status -22 Jan 25 15:04:54 beaglebone user.err kernel: [ 67.337555] pinctrl-single 44e10800.pinmux: could not request pin 103 on device pinctrl-single Which I guess is ok as the first probe already setup the pins, everything then works as it should. Now, when I come to unload + reload the module I get an oops regarding the strmcmp() in pin_request: Jan 25 15:13:25 beaglebone user.debug kernel: [ 578.600746] r0005spi_probe: SPI Bus 2 probed Jan 25 15:13:25 beaglebone user.alert kernel: [ 578.605991] Unable to handle kernel NULL pointer dereference at virtual address 00000000 Jan 25 15:13:25 beaglebone user.alert kernel: [ 578.614641] pgd = cf570000 Jan 25 15:13:25 beaglebone user.alert kernel: [ 578.617578] [00000000] *pgd=8d93a831, *pte=00000000, *ppte=00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.624347] Internal error: Oops: 17 [#1] SMP ARM Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.629303] Modules linked in: r0005spi(O+) [last unloaded: r0005spi] Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.636135] CPU: 0 Tainted: G O (3.8.0-rc5-00538-g2431418-dirty #7) Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.644031] PC is at strcmp+0x4/0x3c Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.647807] LR is at pin_request+0xb0/0x1e8 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.652224] pc : [] lr : [] psr: a0000013 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.652224] sp : cf4dfd38 ip : 00000000 fp : ffffffff Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.664290] r10: 00000000 r9 : 00000000 r8 : 00000059 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.669792] r7 : cf33fe00 r6 : c08413f0 r5 : cf0bb680 r4 : cf0a2280 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.676659] r3 : 00000000 r2 : 00000000 r1 : cf33fe00 r0 : 00000000 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.683531] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.691038] Control: 10c5387d Table: 8f570019 DAC: 00000015 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.697087] Process insmod (pid: 566, stack limit = 0xcf4de240) Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.703318] Stack: (0xcf4dfd38 to 0xcf4e0000) Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.708307] fd20: cf0a2280 00000059 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.717039] fd40: cf33fe00 00000000 cf0a2280 cf52ebc0 c0af6010 c08413f0 00000000 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.725735] fd60: 00000001 c02a99d8 cf756e90 00000003 cf4dfda0 cf52ebc0 cf52ed0c cf756cc0 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.734427] fd80: c0af6010 cf52ed00 bf005650 c02a8018 cf5dfac0 c08411c4 cf756cc0 cf52ed00 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.743121] fda0: c0af6010 c02a8074 cf756c00 cf756cc0 cf335600 bf005218 cf335600 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.751862] fdc0: cf335600 bf005b8c bf005b8c c031e1c0 00000001 c037e678 c037e660 c031dfac Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.764322] fde0: bf005b8c cf335600 cf335600 cf335634 bf005b8c c031e228 00000000 cf4dfe08 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.773168] fe00: bf005b8c c031c53c cf0b5478 cf334880 bf005b8c bf005b8c c0852258 cf4155c0 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.781877] fe20: 00000000 c031d5c4 bf00594c cf0a2488 bf005b8c cf4dff58 00000000 bf005d3c Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.790570] fe40: 00000001 c031e71c 00000000 bf005d30 cf4dff58 00000000 bf005d3c 00000001 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.799262] fe60: bf005650 c0008878 bf005650 00000000 00000001 bf005d30 bf005d30 cf4dff58 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.817450] fe80: 00000000 bf005d3c 00000001 cf6e9880 bf005d78 c008b928 bf005d3c 00007fff Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.826624] fea0: c02a5ed0 00000053 c0875738 0000001c 00000000 c0088aac c07fab0c bf005e84 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.835756] fec0: c0534e14 d09f6970 cf4dfee4 00022008 20000013 c0753164 cf4dff14 c0529a18 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.844875] fee0: d09f9000 b6fca000 00000751 00000000 00000000 00000000 00000000 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.853984] ff00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.863087] ff20: 00000000 00000000 000000d2 b6fc0000 0000a7d1 00022008 00000080 c000e364 Jan 25 15:13:25 beaglebone user.debug kernel: [ 578.600746] r0005spi_probe: SPI Bus 2 probed Jan 25 15:13:25 beaglebone user.alert kernel: [ 578.605991] Unable to handle kernel NULL pointer dereference at virtual address 00000000 Jan 25 15:13:25 beaglebone user.alert kernel: [ 578.614641] pgd = cf570000 Jan 25 15:13:25 beaglebone user.alert kernel: [ 578.617578] [00000000] *pgd=8d93a831, *pte=00000000, *ppte=00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.624347] Internal error: Oops: 17 [#1] SMP ARM Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.629303] Modules linked in: r0005spi(O+) [last unloaded: r0005spi] Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.636135] CPU: 0 Tainted: G O (3.8.0-rc5-00538-g2431418-dirty #7) Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.644031] PC is at strcmp+0x4/0x3c Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.647807] LR is at pin_request+0xb0/0x1e8 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.652224] pc : [] lr : [] psr: a0000013 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.652224] sp : cf4dfd38 ip : 00000000 fp : ffffffff Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.664290] r10: 00000000 r9 : 00000000 r8 : 00000059 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.669792] r7 : cf33fe00 r6 : c08413f0 r5 : cf0bb680 r4 : cf0a2280 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.676659] r3 : 00000000 r2 : 00000000 r1 : cf33fe00 r0 : 00000000 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.683531] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.691038] Control: 10c5387d Table: 8f570019 DAC: 00000015 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.697087] Process insmod (pid: 566, stack limit = 0xcf4de240) Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.703318] Stack: (0xcf4dfd38 to 0xcf4e0000) Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.708307] fd20: cf0a2280 00000059 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.717039] fd40: cf33fe00 00000000 cf0a2280 cf52ebc0 c0af6010 c08413f0 00000000 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.725735] fd60: 00000001 c02a99d8 cf756e90 00000003 cf4dfda0 cf52ebc0 cf52ed0c cf756cc0 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.734427] fd80: c0af6010 cf52ed00 bf005650 c02a8018 cf5dfac0 c08411c4 cf756cc0 cf52ed00 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.743121] fda0: c0af6010 c02a8074 cf756c00 cf756cc0 cf335600 bf005218 cf335600 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.751862] fdc0: cf335600 bf005b8c bf005b8c c031e1c0 00000001 c037e678 c037e660 c031dfac Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.764322] fde0: bf005b8c cf335600 cf335600 cf335634 bf005b8c c031e228 00000000 cf4dfe08 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.773168] fe00: bf005b8c c031c53c cf0b5478 cf334880 bf005b8c bf005b8c c0852258 cf4155c0 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.781877] fe20: 00000000 c031d5c4 bf00594c cf0a2488 bf005b8c cf4dff58 00000000 bf005d3c Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.790570] fe40: 00000001 c031e71c 00000000 bf005d30 cf4dff58 00000000 bf005d3c 00000001 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.799262] fe60: bf005650 c0008878 bf005650 00000000 00000001 bf005d30 bf005d30 cf4dff58 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.817450] fe80: 00000000 bf005d3c 00000001 cf6e9880 bf005d78 c008b928 bf005d3c 00007fff Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.826624] fea0: c02a5ed0 00000053 c0875738 0000001c 00000000 c0088aac c07fab0c bf005e84 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.835756] fec0: c0534e14 d09f6970 cf4dfee4 00022008 20000013 c0753164 cf4dff14 c0529a18 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.844875] fee0: d09f9000 b6fca000 00000751 00000000 00000000 00000000 00000000 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.853984] ff00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.863087] ff20: 00000000 00000000 000000d2 b6fc0000 0000a7d1 00022008 00000080 c000e364 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.872190] ff40: cf4de000 00000000 00000000 c008bce8 00000002 c0529780 d09ef000 0000a7d1 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.881468] ff60: d09f6420 d09f62c8 d09f92f8 00000e98 00001218 bf005bc8 0000000f 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.890834] ff80: 00000022 00000023 0000000e 00000009 00000007 00000000 00000000 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.899961] ffa0: 00022da8 c000e1e0 00000000 00000000 b6fc0000 0000a7d1 00022008 00022da8 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.909073] ffc0: 00000000 00000000 00022da8 00000080 00022098 0000a7d1 00022008 00000000 Jan 25 15:13:25 beaglebone user.emerg kernel: [ 578.918243] ffe0: 4ff71978 bed65ba8 4ff60790 4fe2e870 60000010 b6fc0000 00000000 00000000 Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.927032] [] (strcmp+0x4/0x3c) from [] (pin_request+0xb0/0x1e8) Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.935371] [] (pin_request+0xb0/0x1e8) from [] (pinmux_enable_setting+0x74/0x1a4) Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.945369] [] (pinmux_enable_setting+0x74/0x1a4) from [] (pinctrl_select_state_locked+0xb8/0xf0) Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.956637] [] (pinctrl_select_state_locked+0xb8/0xf0) from [] (pinctrl_select_state+0x24/0x3c) Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.967743] [] (pinctrl_select_state+0x24/0x3c) from [] (r0005spi_probe+0xfc/0x310 [r0005spi]) Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.978751] [] (r0005spi_probe+0xfc/0x310 [r0005spi]) from [] (spi_drv_probe+0x18/0x1c) Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.989093] [] (spi_drv_probe+0x18/0x1c) from [] (driver_probe_device+0x11c/0x330) Jan 25 15:13:25 beaglebone user.warn kernel: [ 578.998970] [] (driver_probe_device+0x11c/0x330) from [] (__driver_attach+0x68/0x8c) Jan 25 15:13:25 beaglebone user.warn kernel: [ 579.009125] [] (__driver_attach+0x68/0x8c) from [] (bus_for_each_dev+0x48/0x80) Jan 25 15:13:25 beaglebone user.warn kernel: [ 579.018774] [] (bus_for_each_dev+0x48/0x80) from [] (bus_add_driver+0xf0/0x248) Jan 25 15:13:25 beaglebone user.warn kernel: [ 579.028379] [] (bus_add_driver+0xf0/0x248) from [] (driver_register+0x9c/0x12c) Jan 25 15:13:25 beaglebone user.warn kernel: [ 579.037982] [] (driver_register+0x9c/0x12c) from [] (do_one_initcall+0x90/0x160) Jan 25 15:13:25 beaglebone user.warn kernel: [ 579.047681] [] (do_one_initcall+0x90/0x160) from [] (load_module+0x1b64/0x1e28) Jan 25 15:13:25 beaglebone user.warn kernel: [ 579.057284] [] (load_module+0x1b64/0x1e28) from [] (sys_init_module+0xfc/0x11c) Jan 25 15:13:25 beaglebone user.warn kernel: [ 579.066891] [] (sys_init_module+0xfc/0x11c) from [] (ret_fast_syscall+0x0/0x30) The pin_request portion of that driver where the traceback points to is as so: dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n", pin, desc->name, owner); if (gpio_range) { /* There's no need to support multiple GPIO requests */ if (desc->gpio_owner) { dev_err(pctldev->dev, "pin %s already requested by %s; cannot claim for %s\n", desc->name, desc->gpio_owner, owner); goto out; } desc->gpio_owner = owner; } else { if (desc->mux_usecount && strcmp(desc->mux_owner, owner)) { dev_err(pctldev->dev, "pin %s already requested by %s; cannot claim for %s\n", desc->name, desc->mux_owner, owner); goto out; } desc->mux_usecount++; if (desc->mux_usecount > 1) return 0; desc->mux_owner = owner; } From what I can gather that means that desc->mux_owner or owner must be an invalid pointer. Is this a bug, or am I abusing the interface in some subtle way? [1] https://pastee.org/vyaz4 [2] https://pastee.org/6e2nt Regards, Jack. -- Jack Mitchell (jack at embed.me.uk) Embedded Systems Engineer http://www.embed.me.uk --