From: André Draszik git@andred.net
If driver probe needs to be deferred, e.g. because ci_hdrc_add_device() isn't ready yet, this driver currently misbehaves badly: a) success is still reported to the driver core (meaning a 2nd probe attempt will never be done), leaving the driver in a dysfunctional state and the hardware unusable
b) driver remove / shutdown OOPSes: [ 206.786916] Unable to handle kernel paging request at virtual address fffffdff [ 206.794148] pgd = 880b9f82 [ 206.796890] [fffffdff] *pgd=abf5e861, *pte=00000000, *ppte=00000000 [ 206.803179] Internal error: Oops: 37 [#1] PREEMPT SMP ARM [ 206.808581] Modules linked in: wl18xx evbug [ 206.813308] CPU: 1 PID: 1 Comm: systemd-shutdow Not tainted 4.19.35+gf345c93b4195 #1 [ 206.821053] Hardware name: Freescale i.MX7 Dual (Device Tree) [ 206.826813] PC is at ci_hdrc_remove_device+0x4/0x20 [ 206.831699] LR is at ci_hdrc_imx_remove+0x20/0xe8 [ 206.836407] pc : [<805cd4b0>] lr : [<805d62cc>] psr: 20000013 [ 206.842678] sp : a806be40 ip : 00000001 fp : 80adbd3c [ 206.847906] r10: 80b1b794 r9 : 80d5dfe0 r8 : a8192c44 [ 206.853136] r7 : 80db93a0 r6 : a8192c10 r5 : a8192c00 r4 : a93a4a00 [ 206.859668] r3 : 00000000 r2 : a8192ce4 r1 : ffffffff r0 : fffffdfb [ 206.866201] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 206.873341] Control: 10c5387d Table: a9e0c06a DAC: 00000051 [ 206.879092] Process systemd-shutdow (pid: 1, stack limit = 0xb271353c) [ 206.885624] Stack: (0xa806be40 to 0xa806c000) [ 206.889992] be40: a93a4a00 805d62cc a8192c1c a8170e10 a8192c10 8049a490 80d04d08 00000000 [ 206.898179] be60: 00000000 80d0da2c fee1dead 00000000 a806a000 00000058 00000000 80148b08 [ 206.906366] be80: 01234567 80148d8c a9858600 00000000 00000000 00000000 00000000 80d04d08 [ 206.914553] bea0: 00000000 00000000 a82741e0 a9858600 00000024 00000002 a9858608 00000005 [ 206.922740] bec0: 0000001e 8022c058 00000000 00000000 a806bf14 a9858600 00000000 a806befc [ 206.930927] bee0: a806bf78 00000000 7ee12c30 8022c18c a806bef8 a806befc 00000000 00000001 [ 206.939115] bf00: 00000000 00000024 a806bf14 00000005 7ee13b34 7ee12c68 00000004 7ee13f20 [ 206.947302] bf20: 00000010 7ee12c7c 00000005 7ee12d04 0000000a 76e7dc00 00000001 80d0f140 [ 206.955490] bf40: ab637880 a974de40 60000013 80d0f140 ab6378a0 80d04d08 a8080470 a9858600 [ 206.963677] bf60: a9858600 00000000 00000000 8022c24c 00000000 80144310 00000000 00000000 [ 206.971864] bf80: 80101204 80d04d08 00000000 80d04d08 00000000 00000000 00000003 00000058 [ 206.980051] bfa0: 80101204 80101000 00000000 00000000 fee1dead 28121969 01234567 00000000 [ 206.988237] bfc0: 00000000 00000000 00000003 00000058 00000000 00000000 00000000 00000000 [ 206.996425] bfe0: 0049ffb0 7ee13d58 0048a84b 76f245a6 60000030 fee1dead 00000000 00000000 [ 207.004622] [<805cd4b0>] (ci_hdrc_remove_device) from [<805d62cc>] (ci_hdrc_imx_remove+0x20/0xe8) [ 207.013509] [<805d62cc>] (ci_hdrc_imx_remove) from [<8049a490>] (device_shutdown+0x16c/0x218) [ 207.022050] [<8049a490>] (device_shutdown) from [<80148b08>] (kernel_restart+0xc/0x50) [ 207.029980] [<80148b08>] (kernel_restart) from [<80148d8c>] (sys_reboot+0xf4/0x1f0) [ 207.037648] [<80148d8c>] (sys_reboot) from [<80101000>] (ret_fast_syscall+0x0/0x54) [ 207.045308] Exception stack(0xa806bfa8 to 0xa806bff0) [ 207.050368] bfa0: 00000000 00000000 fee1dead 28121969 01234567 00000000 [ 207.058554] bfc0: 00000000 00000000 00000003 00000058 00000000 00000000 00000000 00000000 [ 207.066737] bfe0: 0049ffb0 7ee13d58 0048a84b 76f245a6 [ 207.071799] Code: ebffffa8 e3a00000 e8bd8010 e92d4010 (e5904004) [ 207.078021] ---[ end trace be47424e3fd46e9f ]--- [ 207.082647] Kernel panic - not syncing: Fatal exception [ 207.087894] ---[ end Kernel panic - not syncing: Fatal exception ]---
c) the error path in combination with driver removal causes imbalanced calls to the clk_*() and pm_()* APIs
a) happens because the original intended return value is overwritten (with 0) by the return code of regulator_disable() in ci_hdrc_imx_probe()'s error path b) happens because ci_pdev is -EPROBE_DEFER, which causes ci_hdrc_remove_device() to OOPS
Fix a) by being more careful in ci_hdrc_imx_probe()'s error path and not overwriting the real error code
Fix b) by calling the respective cleanup functions during remove only when needed (when ci_pdev != NULL, i.e. when everything was initialised correctly). This also has the side effect of not causing imbalanced clk_*() and pm_*() API calls as part of the error code path.
Fixes: 7c8e8909417e ("usb: chipidea: imx: add HSIC support") Signed-off-by: André Draszik git@andred.net Cc: stable stable@vger.kernel.org CC: Peter Chen Peter.Chen@nxp.com CC: Greg Kroah-Hartman gregkh@linuxfoundation.org CC: Shawn Guo shawnguo@kernel.org CC: Sascha Hauer s.hauer@pengutronix.de CC: Pengutronix Kernel Team kernel@pengutronix.de CC: Fabio Estevam festevam@gmail.com CC: NXP Linux Team linux-imx@nxp.com CC: linux-usb@vger.kernel.org CC: linux-arm-kernel@lists.infradead.org CC: linux-kernel@vger.kernel.org Link: https://lore.kernel.org/r/20190810150758.17694-1-git@andred.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/chipidea/ci_hdrc_imx.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/drivers/usb/chipidea/ci_hdrc_imx.c b/drivers/usb/chipidea/ci_hdrc_imx.c index a76708501236d..5faae96735e62 100644 --- a/drivers/usb/chipidea/ci_hdrc_imx.c +++ b/drivers/usb/chipidea/ci_hdrc_imx.c @@ -453,9 +453,11 @@ static int ci_hdrc_imx_probe(struct platform_device *pdev) imx_disable_unprepare_clks(dev); disable_hsic_regulator: if (data->hsic_pad_regulator) - ret = regulator_disable(data->hsic_pad_regulator); + /* don't overwrite original ret (cf. EPROBE_DEFER) */ + regulator_disable(data->hsic_pad_regulator); if (pdata.flags & CI_HDRC_PMQOS) pm_qos_remove_request(&data->pm_qos_req); + data->ci_pdev = NULL; return ret; }
@@ -468,14 +470,17 @@ static int ci_hdrc_imx_remove(struct platform_device *pdev) pm_runtime_disable(&pdev->dev); pm_runtime_put_noidle(&pdev->dev); } - ci_hdrc_remove_device(data->ci_pdev); + if (data->ci_pdev) + ci_hdrc_remove_device(data->ci_pdev); if (data->override_phy_control) usb_phy_shutdown(data->phy); - imx_disable_unprepare_clks(&pdev->dev); - if (data->plat_data->flags & CI_HDRC_PMQOS) - pm_qos_remove_request(&data->pm_qos_req); - if (data->hsic_pad_regulator) - regulator_disable(data->hsic_pad_regulator); + if (data->ci_pdev) { + imx_disable_unprepare_clks(&pdev->dev); + if (data->plat_data->flags & CI_HDRC_PMQOS) + pm_qos_remove_request(&data->pm_qos_req); + if (data->hsic_pad_regulator) + regulator_disable(data->hsic_pad_regulator); + }
return 0; }