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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 <geert+renesas@glider.be>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
This commit is contained in:
Geert Uytterhoeven 2015-02-23 16:37:24 +01:00 committed by Eduardo Valentin
parent 12ca718846
commit 0b37a83a91
1 changed files with 9 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/thermal/rcar_thermal.c
View File

@ -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);