Messages in this thread | | | Subject | Re: [PATCH v2 4/4] ARM: OMAP2+: omap_device: fix crash on omap_device removal | From | Grygorii Strashko <> | Date | Fri, 29 Jul 2016 15:52:39 +0300 |
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On 07/29/2016 08:15 AM, Peter Ujfalusi wrote: > On 07/28/16 20:50, Grygorii Strashko wrote: >> Below call chain causes system crash when OMAP device is >> removed by calling of_platform_depopulate()/device_del(): > > Should you swap 3 <-> 4 in the series? > Currently patch 3 will introduce the crash you are fixing in patch 4...
No. The key function here is device_del() - of_device_unregister(), which was used previously has the same issue: of_device_unregister() -> device_unregister() ->device_del()
In general all these patches are independent and they were created just in bugs detection order.
> >> >> device_del() >> - blocking_notifier_call_chain(&dev->bus->p->bus_notifier, >> BUS_NOTIFY_DEL_DEVICE, dev); >> - _omap_device_notifier_call() >> - omap_device_delete() >> - od->pdev->archdata.od = NULL; >> kfree(od->hwmods); >> kfree(od); >> - bus_remove_device() >> - device_release_driver() >> - __device_release_driver() >> - pm_runtime_get_sync() >> - _od_runtime_resume() >> - omap_hwmod_enable() <- OOPS od's delted already >> >> Backtrace: >> Unable to handle kernel NULL pointer dereference at virtual address 0000000d >> pgd = eb100000 >> [0000000d] *pgd=ad6e1831, *pte=00000000, *ppte=00000000 >> Internal error: Oops: 17 [#1] PREEMPT SMP ARM >> CPU: 1 PID: 1273 Comm: modprobe Not tainted 4.4.15-rt19-00115-ge4d3cd3-dirty #68 >> Hardware name: Generic DRA74X (Flattened Device Tree) >> task: eb1ee800 ti: ec962000 task.ti: ec962000 >> PC is at omap_device_enable+0x10/0x90 >> LR is at _od_runtime_resume+0x10/0x24 >> [...] >> [<c00299dc>] (omap_device_enable) from [<c0029a6c>] (_od_runtime_resume+0x10/0x24) >> [<c0029a6c>] (_od_runtime_resume) from [<c04ad404>] (__rpm_callback+0x20/0x34) >> [<c04ad404>] (__rpm_callback) from [<c04ad438>] (rpm_callback+0x20/0x80) >> [<c04ad438>] (rpm_callback) from [<c04aee28>] (rpm_resume+0x48c/0x964) >> [<c04aee28>] (rpm_resume) from [<c04af360>] (__pm_runtime_resume+0x60/0x88) >> [<c04af360>] (__pm_runtime_resume) from [<c04a4974>] (__device_release_driver+0x30/0x100) >> [<c04a4974>] (__device_release_driver) from [<c04a4a60>] (device_release_driver+0x1c/0x28) >> [<c04a4a60>] (device_release_driver) from [<c04a38c0>] (bus_remove_device+0xec/0x144) >> [<c04a38c0>] (bus_remove_device) from [<c04a0764>] (device_del+0x10c/0x210) >> [<c04a0764>] (device_del) from [<c04a67b0>] (platform_device_del+0x18/0x84) >> [<c04a67b0>] (platform_device_del) from [<c04a6828>] (platform_device_unregister+0xc/0x20) >> [<c04a6828>] (platform_device_unregister) from [<c05adcfc>] (of_platform_device_destroy+0x8c/0x90) >> [<c05adcfc>] (of_platform_device_destroy) from [<c04a02f0>] (device_for_each_child+0x4c/0x78) >> [<c04a02f0>] (device_for_each_child) from [<c05adc5c>] (of_platform_depopulate+0x30/0x44) >> [<c05adc5c>] (of_platform_depopulate) from [<bf123920>] (cpsw_remove+0x68/0xf4 [ti_cpsw]) >> [<bf123920>] (cpsw_remove [ti_cpsw]) from [<c04a68d8>] (platform_drv_remove+0x24/0x3c) >> [<c04a68d8>] (platform_drv_remove) from [<c04a49c8>] (__device_release_driver+0x84/0x100) >> [<c04a49c8>] (__device_release_driver) from [<c04a4b20>] (driver_detach+0xac/0xb0) >> [<c04a4b20>] (driver_detach) from [<c04a3be8>] (bus_remove_driver+0x60/0xd4) >> [<c04a3be8>] (bus_remove_driver) from [<c00d9870>] (SyS_delete_module+0x184/0x20c) >> [<c00d9870>] (SyS_delete_module) from [<c0010540>] (ret_fast_syscall+0x0/0x1c) >> Code: e3500000 e92d4070 1590630c 01a06000 (e5d6300d) >> >> Hence, fix it by using BUS_NOTIFY_REMOVED_DEVICE event for OMAP device >> deletion which is sent when DD has finished processing of device >> deletion. >> >> Cc: Tony Lindgren <tony@atomide.com> >> Cc: Tero Kristo <t-kristo@ti.com> >> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> >> --- >> arch/arm/mach-omap2/omap_device.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c >> index f7ff3b9..208f115 100644 >> --- a/arch/arm/mach-omap2/omap_device.c >> +++ b/arch/arm/mach-omap2/omap_device.c >> @@ -194,7 +194,7 @@ static int _omap_device_notifier_call(struct notifier_block *nb, >> int err; >> >> switch (event) { >> - case BUS_NOTIFY_DEL_DEVICE: >> + case BUS_NOTIFY_REMOVED_DEVICE: >> if (pdev->archdata.od) >> omap_device_delete(pdev->archdata.od); >> break; >> > >
-- regards, -grygorii
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