On Mon, Mar 03, 2014 at 08:53:31PM +0000, Sylwester Nawrocki wrote:
> Hi,
>
> On 03/03/2014 08:04 PM, Tomasz Figa wrote:
> > On 03.03.2014 19:57, Javi Merino wrote:
> >> Hi,
> >>
> >> Commit fcb0ee6a3d (clk: Implement clk_unregister) added calls to
> >> kref_get() and kref_put() to __clk_get() and __clk_put() without
> >> checking if clk is not NULL:
> >>
> >>> @@ -1987,6 +2097,7 @@ int __clk_get(struct clk *clk)
> >>> if (clk && !try_module_get(clk->owner))
> >>> return 0;
> >>>
> >>> + kref_get(&clk->ref);
> >>> return 1;
> >>> }
> >>>
> >>> @@ -1995,6 +2106,10 @@ void __clk_put(struct clk *clk)
> >>> if (WARN_ON_ONCE(IS_ERR(clk)))
> >>> return;
> >>>
> >>> + clk_prepare_lock();
> >>> + kref_put(&clk->ref, __clk_release);
> >>> + clk_prepare_unlock();
> >>> +
> >>> if (clk)
> >>> module_put(clk->owner);
> >>> }
> >>
> >> Before this commit, these functions allowed clk to be NULL. In
> >> particular, the "if (clk)" in __clk_put() is now useless, as clk has
> >> been dereferenced by the time you reach it.
> >>
> >> This causes Arndale Octa to panic on boot:
> >>
> >> 8<---
> >> [ 7.430000] Creating amba device /amba/pdma@121B0000
> >> [ 7.435000] create child: /amba/mdma@10800000
> >> [ 7.440000] Creating amba device /amba/mdma@10800000
> >> [ 7.445000] Unable to handle kernel NULL pointer dereference at virtual address 00000050
> >>
> >> [ 7.450000] pgd = c0004000
> >> [ 7.450000] [00000050] *pgd=00000000
> >> [ 7.455000] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
> >> [ 7.455000] Modules linked in:
> >> [ 7.455000] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0-rc3-00003-gb6026fe-dirty #23
> >>
> >> [ 7.455000] task: ee0a8000 ti: ee0a6000 task.ti: ee0a6000
> >> [ 7.455000] PC is at __clk_get+0x24/0x84
> >> [ 7.455000] LR is at of_clk_get+0x5c/0x74
> [...]
> >>
> >> [ 7.455000] [<c02e5cc8>] (__clk_get) from [<c02e34b8>] (of_clk_get+0x5c/0x74)
> >>
> >> [ 7.455000] [<c02e34b8>] (of_clk_get) from [<c02e350c>] (of_clk_get_by_name+0x3c/0xb0)
> >>
> >> [ 7.455000] [<c02e350c>] (of_clk_get_by_name) from [<c02e35a4>] (clk_get+0x24/0x44)
> >>
> >> [ 7.455000] [<c02e35a4>] (clk_get) from [<c01ee6fc>] (amba_get_enable_pclk+0x10/0x60)
> >>
> >> [ 7.455000] [<c01ee6fc>] (amba_get_enable_pclk) from [<c01ee7ec>] (amba_device_add+0xa0/0x1e0)
> >>
> >> [ 7.455000] [<c01ee7ec>] (amba_device_add) from [<c02e0f94>] (of_platform_bus_create+0x190/0x308)
> >>
> >> [ 7.455000] [<c02e0f94>] (of_platform_bus_create) from [<c02e103c>] (of_platform_bus_create+0x238
> >>
> >> [ 7.455000] [<c02e103c>] (of_platform_bus_create) from [<c02e116c>] (of_platform_populate+0x60/0x
> >>
> >> [ 7.455000] [<c02e116c>] (of_platform_populate) from [<c04cc280>] (customize_machine+0x1c/0x40)
> >>
> >> [ 7.455000] [<c04cc280>] (customize_machine) from [<c00088e8>] (do_one_initcall+0xe4/0x140)
> >>
> >> [ 7.455000] [<c00088e8>] (do_one_initcall) from [<c04c9c50>] (kernel_init_freeable+0xfc/0x1c8)
> >>
> >> [ 7.455000] [<c04c9c50>] (kernel_init_freeable) from [<c038447c>] (kernel_init+0x8/0xe4)
> >>
> >> [ 7.455000] [<c038447c>] (kernel_init) from [<c000e4b8>] (ret_from_fork+0x14/0x3c)
> >>
> >> [ 7.455000] Code: e3500000 08bd8010 e2843050 f57ff05b (e1932f9f)
> >> [ 7.460000] ---[ end trace fe5cfa405506a77d ]---
> >> [ 7.460000] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
> >>
> >> 8<---
> >>
> >> I've tried putting "if (clk)" around the calls to kref_get() and
> >> kref_put(), but that makes the Octa fail to boot like 3.13 did: when
> >> tries to mount root.
> >>
> >> What works for me so far is to remove the offending nodes from the DT:
> >>
> >> 8<---
> >> diff --git a/arch/arm/boot/dts/exynos5420.dtsi b/arch/arm/boot/dts/exynos5420.dtsi
> >>
> >> index 8db792b..c4ab992 100644
> >> --- a/arch/arm/boot/dts/exynos5420.dtsi
> >> +++ b/arch/arm/boot/dts/exynos5420.dtsi
> >> @@ -303,27 +303,6 @@
> >> #dma-requests = <32>;
> >> };
> >>
> >> - mdma0: mdma@10800000 {
> >> - compatible = "arm,pl330", "arm,primecell";
> >> - reg = <0x10800000 0x1000>;
> >> - interrupts = <0 33 0>;
> >> - clocks = <&clock 473>;
> >> - clock-names = "apb_pclk";
> >> - #dma-cells = <1>;
> >> - #dma-channels = <8>;
> >> - #dma-requests = <1>;
> >> - };
> >> -
> >> - mdma1: mdma@11C10000 {
> >> - compatible = "arm,pl330", "arm,primecell";
> >> - reg = <0x11C10000 0x1000>;
> >> - interrupts = <0 124 0>;
> >> - clocks = <&clock 442>;
> >> - clock-names = "apb_pclk";
> >> - #dma-cells = <1>;
> >> - #dma-channels = <8>;
> >> - #dma-requests = <1>;
> >> - };
> >> };
> >>
> >> spi_0: spi@12d20000 {
> >> 8<---
> >>
> >> With this the Arndale Octa boots. This issue is present from 3.14-rc1
> >> to 3.14-rc5. Any idea how this should be properly fixed in mainline?
> >
> > This should be fixed with [1], which was supposed to be merged for
> > 3.14-rc5. Mike?
> >
> > [1] https://git.linaro.org/people/mike.turquette/linux.git/commit/00efcb1c8e1c3c5e5d3ce6f0682d66402911a84f
This patch fixes the kernel panic, yes. Hopefully it'll be in -rc6.
> You may also want to consider this patch:
> https://patchwork.kernel.org/patch/3597711
That didn't change anything.
> It looks like there is no clock registered for the mdm0 PL330 device
> in exynos5420 clocks driver (drivers/clk/samsung/clk-exynos5420.c).
>
> So a proper fix, except of a patch pointed out by Tomasz, would be to
> add a corresponding entry to exynos5420_gate_clocks[] array (the mdm0
> gate clock seems to be already documented in Documentation/devicetree/
> bindings/clock/exynos5420-clock.txt).
>
> AFAIU, you're still having problems even with patch [1] applied ?
Yes, with [1] applied I don't get a kernel panic but the kernel fails
to boot later on with an Imprecise external abort. Removing the mdma
nodes from the dts gets rid of that. I guess what's missing is what
you said: clocks for the mdma devices.
8<---
[ 8.060000] mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 52000000Hz, actual 50000000HZ d)
[ 8.070000] Registering SWP/SWPB emulation handler
[ 8.075000] s3c-rtc 101e0000.rtc: setting system clock to 2000-01-01 00:00:00 UTC (946684800)
[ 8.080000] mmc_host mmc0: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ )
[ 8.090000] Freeing unused kernel memory: 220K (c04c1000 - c04f8000)
[ 8.100000] Unhandled fault: imprecise external abort (0x1406) at 0x00000000
[ 8.105000] mmc0: new high speed DDR MMC card at address 0001
[ 8.110000] mmcblk0: mmc0:0001 M4G1FB 3.64 GiB
[ 8.115000] mmcblk0boot0: mmc0:0001 M4G1FB partition 1 1.00 MiB
[ 8.120000] mmcblk0boot1: mmc0:0001 M4G1FB partition 2 1.00 MiB
[ 8.125000] mmcblk0rpmb: mmc0:0001 M4G1FB partition 3 128 KiB
[ 8.135000] mmcblk0: p1 p2 p3 p4
[ 8.140000] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000007
[ 8.140000]
[ 8.140000] CPU: 0 PID: 1 Comm: init Not tainted 3.14.0-rc5-00002-g691b10f #189
[ 8.140000] [<c0013e24>] (unwind_backtrace) from [<c0011238>] (show_stack+0x10/0x14)
[ 8.140000] [<c0011238>] (show_stack) from [<c038218c>] (dump_stack+0x64/0xb4)
[ 8.140000] [<c038218c>] (dump_stack) from [<c037f6f4>] (panic+0x8c/0x1dc)
[ 8.140000] [<c037f6f4>] (panic) from [<c001f178>] (do_exit+0x80c/0x8b8)
[ 8.140000] [<c001f178>] (do_exit) from [<c001f310>] (do_group_exit+0x3c/0xb0)
[ 8.140000] [<c001f310>] (do_group_exit) from [<c00298a0>] (get_signal_to_deliver+0x278/0x500)
[ 8.140000] [<c00298a0>] (get_signal_to_deliver) from [<c001076c>] (do_signal+0x78/0x398)
[ 8.140000] [<c001076c>] (do_signal) from [<c0010db4>] (do_work_pending+0x64/0xac)
[ 8.140000] [<c0010db4>] (do_work_pending) from [<c000e460>] (work_pending+0xc/0x20)
8<---
[1] https://git.linaro.org/people/mike.turquette/linux.git/commit/00efcb1c8e1c3c5e5d3ce6f0682d66402911a84f
Cheers,
Javi
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