From: Ambresh K <ambresh@xxxxxx> On a possible HW bug or in-correct configuration of clk_sel bits in bootloaders, there are high probablity of returning a value greater than available parent clocks for a MUX clk. Sensing invalid parent index, clk_mux_get_parent returns -EINVALID. Due to function's "u8" return type it will get converted into signed value, thus causing following pointer dereference on test platform. Patch series fixes the bug and also minor optimzation while re-parenting orphan clk. M[ 0.000000] dra7xx_clk_init: clk init (gpu_core_gclk_mux)^M ^M[ 0.000000] Unable to handle kernel NULL pointer dereference at virtual address 00000000^M ^M[ 0.000000] pgd = c0004000^M ^M[ 0.000000] [00000000] *pgd=00000000^M ^M[ 0.000000] Internal error: Oops: 5 [#1] SMP ARM^M ^M[ 0.000000] Modules linked in:^M ^M[ 0.000000] CPU: 0 Not tainted (3.8.4-gb746a7c-dirty #59)^M ^M[ 0.000000] PC is at strcmp+0x8/0x34^M ^M[ 0.000000] LR is at __clk_init+0x16c/0x3cc^M ^M[ 0.000000] pc : [<c033af7c>] lr : [<c04ca314>] psr: 600001d3^M ^M[ 0.000000] sp : c09d1f70 ip : c0a12b3c fp : 00000000^M ^M[ 0.000000] r10: 00000000 r9 : c0a0f8b4 r8 : 8000406a^M ^M[ 0.000000] r7 : c09d1fe4 r6 : c0a0ff40 r5 : c102888c r4 : c0a0ff40^M ^M[ 0.000000] r3 : 00000000 r2 : 00000067 r1 : 00000000 r0 : c0731c14^M ^M[ 0.000000] Flags: nZCv IRQs off FIQs off Mode SVC_32 ISA ARM Segment kernel^M ^M[ 0.000000] Control: 10c53c7d Table: 8000406a DAC: 00000017^M ^M[ 0.000000] Process swapper (pid: 0, stack limit = 0xc09d0240)^M ^M[ 0.000000] Stack: (0xc09d1f70 to 0xc09d2000)^M ^M[ 0.000000] 1f60: 00000000 c05c0518 c0731dd4 c0a0c9f8^M ^M[ 0.000000] 1f80: c0a0d340 c0838f58 c09d1fe4 8000406a 412fc0f2 00000000 00000000 c0814370^M ^M[ 0.000000] 1fa0: 00000005 c0837140 c0a92b78 c0806124 00000000 c09d1fc4 c100d780 c09d0000^M ^M[ 0.000000] 1fc0: 00000001 00000000 c09dd6c4 c0802728 00000000 00000000 00000000 00000000^M ^M[ 0.000000] 1fe0: 00000000 c0838f58 10c53c7d c09d894c c0838f54 80008078 00000000 00000000^M ^M[ 0.000000] [<c033af7c>] (strcmp+0x8/0x34) from [<c04ca314>] (__clk_init+0x16c/0x3cc)^M ^M[ 0.000000] [<c04ca314>] (__clk_init+0x16c/0x3cc) from [<c0814370>] (dra7xx_clk_init+0x5c/0xa8)^M ^M[ 0.000000] [<c0814370>] (dra7xx_clk_init+0x5c/0xa8) from [<c0806124>] (setup_arch+0x148/0x194)^M ^M[ 0.000000] [<c0806124>] (setup_arch+0x148/0x194) from [<c0802728>] (start_kernel+0x80/0x2b8)^M ^M[ 0.000000] [<c0802728>] (start_kernel+0x80/0x2b8) from [<80008078>] (0x80008078)^M ^M[ 0.000000] Code: e8bd0070 e12fff1e e3a03000 e7d02003 (e7d1c003) ^M ^M[ 0.000000] ---[ end trace 1b75b31a2719ed1c ]---^M ^M[ 0.000000] Kernel panic - not syncing: Fatal exception^M Note: 1) With omap2plus_defconfig following warning are generated with the patches applied, will fix it on reviewing the patches series. 2) Other platforms too might have similar warnings. arch/arm/mach-omap2/cclock2420_data.c:116: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock2420_data.c:369: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock2420_data.c:417: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock2420_data.c:745: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock2430_data.c:116: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock2430_data.c:349: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock2430_data.c:397: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock2430_data.c:724: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock3xxx_data.c:118: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock3xxx_data.c:257: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock3xxx_data.c:367: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock3xxx_data.c:585: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock3xxx_data.c:619: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock3xxx_data.c:1176: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock3xxx_data.c:2600: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock3xxx_data.c:3091: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock44xx_data.c:159: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock44xx_data.c:257: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock44xx_data.c:327: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock44xx_data.c:334: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock44xx_data.c:398: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock44xx_data.c:614: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock44xx_data.c:1329: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock33xx_data.c:105: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock33xx_data.c:182: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock33xx_data.c:225: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock33xx_data.c:481: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock33xx_data.c:601: warning: initialization from incompatible pointer type arch/arm/mach-omap2/cclock33xx_data.c:644: warning: initialization from incompatible pointer type Ambresh K (3): clk: fix clk_mux_get_parent return's signed value clk: skip re-parenting orphan clk clk: Avoid re-parenting orphan clk's having invalid parent index. drivers/clk/clk-mux.c | 2 +- drivers/clk/clk.c | 37 ++++++++++++++++++++++++++++++++++--- include/linux/clk-provider.h | 4 ++-- 3 files changed, 37 insertions(+), 6 deletions(-) -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
