From mboxrd@z Thu Jan 1 00:00:00 1970 From: tomasz.figa@gmail.com (Tomasz Figa) Date: Mon, 03 Mar 2014 20:04:25 +0100 Subject: [REGRESSION] Arndale Octa panics when booting 3.14-rc1 In-Reply-To: <20140303185755.GA11460@e102654-lin.cambridge.arm.com> References: <20140303185755.GA11460@e102654-lin.cambridge.arm.com> Message-ID: <5314D239.7090001@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, 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 at 121B0000 > [ 7.435000] create child: /amba/mdma at 10800000 > [ 7.440000] Creating amba device /amba/mdma at 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] pc : [] lr : [] psr: 60000113 > [ 7.455000] sp : ee0a7d78 ip : ee0a7d88 fp : 00000001 > [ 7.455000] r10: f001c000 r9 : ee193a10 r8 : 00000000 > [ 7.455000] r7 : 00000000 r6 : ee7dedb4 r5 : c045e930 r4 : 00000000 > [ 7.455000] r3 : 00000050 r2 : 000001d9 r1 : c0575df8 r0 : 00000000 > [ 7.455000] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel > [ 7.455000] Control: 10c5387d Table: 2000406a DAC: 00000015 > [ 7.455000] Process swapper/0 (pid: 1, stack limit = 0xee0a6240) > [ 7.455000] Stack: (0xee0a7d78 to 0xee0a8000) > [ 7.455000] 7d60: 00000000 c02e34b8 > [ 7.455000] 7d80: ee0a7d88 c02df2e4 ee7dd984 00000001 000001d9 ee7dedb4 00000000 c02df300 > [ 7.455000] 7da0: ee1779c0 c045e930 ee7dedb4 00000000 ee1779c0 c02e350c 00000000 ee1779c0 > [ 7.455000] 7dc0: c045e930 00001000 00000000 c02e35a4 00000000 ee194000 ee194128 c01ee6fc > [ 7.455000] 7de0: ee194000 ee194128 00001000 c01ee7ec 00000000 ee7dedb4 ee194000 00000009 > [ 7.455000] 7e00: ee19416c 00000000 00000001 c02e0f94 c053f0f2 00000000 ee193a10 c03b6880 > [ 7.455000] 7e20: 00000000 ee7dedb4 ee193a10 00000000 00000000 00000001 00000000 c0385924 > [ 7.455000] 7e40: c047832c ee7dea18 00000000 ee7dedb4 ee193a10 00000000 00000000 00000001 > [ 7.455000] 7e60: 00000000 c02e103c 00000001 c04c9500 00000079 c03b6880 00000000 00000000 > [ 7.455000] 7e80: 60000113 c05352d8 00000000 00000000 c03b6880 00000001 00000000 ee7dea18 > [ 7.455000] 7ea0: ee7d6e28 00000000 00000000 c03b6880 00000000 00000001 00000000 c02e116c > [ 7.455000] 7ec0: 00000001 00000000 c04cc264 ee0a6000 c04ec240 00000000 c04c9500 c04fec18 > [ 7.455000] 7ee0: 00000079 c04cc280 00000000 c00088e8 00000000 c038cb70 0000006d 00000000 > [ 7.455000] 7f00: 00000001 c0101a2c ee15ce00 ee15d080 60000100 c050fb40 60000113 c050fb40 > [ 7.455000] 7f20: c04ec230 c050fb3c c050fb3c c04a79f0 c04a79f0 ef7fc9ff ef7fc9fb c0034f40 > [ 7.455000] 7f40: c043e434 c04a7260 00000003 00000003 00000000 c04ec260 00000003 c04ec240 > [ 7.455000] 7f60: c053b2c0 c04c9500 c04fec18 00000079 00000000 c04c9c50 00000003 00000003 > [ 7.455000] 7f80: c04c9500 c003e450 00000000 c0384474 00000000 00000000 00000000 00000000 > [ 7.455000] 7fa0: 00000000 c038447c 00000000 c000e4b8 00000000 00000000 00000000 00000000 > [ 7.455000] 7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > [ 7.455000] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff > [ 7.455000] [] (__clk_get) from [] (of_clk_get+0x5c/0x74) > [ 7.455000] [] (of_clk_get) from [] (of_clk_get_by_name+0x3c/0xb0) > [ 7.455000] [] (of_clk_get_by_name) from [] (clk_get+0x24/0x44) > [ 7.455000] [] (clk_get) from [] (amba_get_enable_pclk+0x10/0x60) > [ 7.455000] [] (amba_get_enable_pclk) from [] (amba_device_add+0xa0/0x1e0) > [ 7.455000] [] (amba_device_add) from [] (of_platform_bus_create+0x190/0x308) > [ 7.455000] [] (of_platform_bus_create) from [] (of_platform_bus_create+0x238 > [ 7.455000] [] (of_platform_bus_create) from [] (of_platform_populate+0x60/0x > [ 7.455000] [] (of_platform_populate) from [] (customize_machine+0x1c/0x40) > [ 7.455000] [] (customize_machine) from [] (do_one_initcall+0xe4/0x140) > [ 7.455000] [] (do_one_initcall) from [] (kernel_init_freeable+0xfc/0x1c8) > [ 7.455000] [] (kernel_init_freeable) from [] (kernel_init+0x8/0xe4) > [ 7.455000] [] (kernel_init) from [] (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 at 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 at 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 at 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 Best regards, Tomasz