From 0b37a83a91e885250c68546ce7271ce722120c99 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Mon, 23 Feb 2015 16:37:24 +0100 Subject: [PATCH] thermal: rcar: Fix race condition between init and interrupt As soon as the interrupt has been enabled by devm_request_irq(), the interrupt routine may be called, depending on the current status of the hardware. However, at that point rcar_thermal_common hasn't been initialized complely yet. E.g. rcar_thermal_common.base is still NULL, causing a NULL pointer dereference: Unable to handle kernel NULL pointer dereference at virtual address 0000000c pgd = c0004000 [0000000c] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.19.0-rc7-ape6evm-04564-gb6e46cb7cbe82389 #30 Hardware name: Generic R8A73A4 (Flattened Device Tree) task: ee8953c0 ti: ee896000 task.ti: ee896000 PC is at rcar_thermal_irq+0x1c/0xf0 LR is at _raw_spin_lock_irqsave+0x48/0x54 Postpone the call to devm_request_irq() until all initialization has been done to fix this. Signed-off-by: Geert Uytterhoeven Acked-by: Kuninori Morimoto Signed-off-by: Eduardo Valentin --- drivers/thermal/rcar_thermal.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/drivers/thermal/rcar_thermal.c b/drivers/thermal/rcar_thermal.c index 2580a48..3c2c172 100644 --- a/drivers/thermal/rcar_thermal.c +++ b/drivers/thermal/rcar_thermal.c @@ -387,21 +387,9 @@ static int rcar_thermal_probe(struct platform_device *pdev) irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (irq) { - int ret; - /* * platform has IRQ support. * Then, driver uses common registers - */ - - ret = devm_request_irq(dev, irq->start, rcar_thermal_irq, 0, - dev_name(dev), common); - if (ret) { - dev_err(dev, "irq request failed\n "); - return ret; - } - - /* * rcar_has_irq_support() will be enabled */ res = platform_get_resource(pdev, IORESOURCE_MEM, mres++); @@ -456,8 +444,16 @@ static int rcar_thermal_probe(struct platform_device *pdev) } /* enable temperature comparation */ - if (irq) + if (irq) { + ret = devm_request_irq(dev, irq->start, rcar_thermal_irq, 0, + dev_name(dev), common); + if (ret) { + dev_err(dev, "irq request failed\n "); + goto error_unregister; + } + rcar_thermal_common_write(common, ENR, enr_bits); + } platform_set_drvdata(pdev, common); -- 2.7.4