4.17-stable review patch. If anyone has any objections, please let me know.
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From: Alexandre Belloni alexandre.belloni@bootlin.com
[ Upstream commit 63d22063073b0ab46d1e06fe633fb5de8f5c58e1 ]
The probe function is not allowed to fail after the RTC is registered because the following may happen:
CPU0: CPU1: sys_load_module() do_init_module() do_one_initcall() cmos_do_probe() rtc_device_register() __register_chrdev() cdev->owner = struct module* open("/dev/rtc0") rtc_device_unregister() module_put() free_module() module_free(mod->module_core) /* struct module *module is now freed */ chrdev_open() spin_lock(cdev_lock) cdev_get() try_module_get() module_is_live() /* dereferences already freed struct module* */
Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/rtc/rtc-tps6586x.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)
--- a/drivers/rtc/rtc-tps6586x.c +++ b/drivers/rtc/rtc-tps6586x.c @@ -276,14 +276,15 @@ static int tps6586x_rtc_probe(struct pla device_init_wakeup(&pdev->dev, 1);
platform_set_drvdata(pdev, rtc); - rtc->rtc = devm_rtc_device_register(&pdev->dev, dev_name(&pdev->dev), - &tps6586x_rtc_ops, THIS_MODULE); + rtc->rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(rtc->rtc)) { ret = PTR_ERR(rtc->rtc); - dev_err(&pdev->dev, "RTC device register: ret %d\n", ret); + dev_err(&pdev->dev, "RTC allocate device: ret %d\n", ret); goto fail_rtc_register; }
+ rtc->rtc->ops = &tps6586x_rtc_ops; + ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL, tps6586x_rtc_irq, IRQF_ONESHOT, @@ -294,6 +295,13 @@ static int tps6586x_rtc_probe(struct pla goto fail_rtc_register; } disable_irq(rtc->irq); + + ret = rtc_register_device(rtc->rtc); + if (ret) { + dev_err(&pdev->dev, "RTC device register: ret %d\n", ret); + goto fail_rtc_register; + } + return 0;
fail_rtc_register: