Re: 750gx cpufreq induced kernel panic in 2.6.36
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2011-01-26 04:34:00
On Tue, 2011-01-25 at 17:54 -0600, kevin diggs wrote:
quoted hunk ↗ jump to hunk
Hi, The cpufreq driver I wrote for the 750gx causes a kernel panic in 2.6.36. This is from a screen shot: [c6035f30] [c001014c] timer_interrupt+0x13c/0x19c [c6035f40] [c0013294] ret_from_except+0x0/0x14--- Exception: 901 at 0x1000c694 LR = 0x1000f3e4Instruction dump: 4bffff48 38610008 4be7b2b1 4bffff9c 9421fff0 7c0802a6 bfc10xxx 90010014 7c0000a6 68008000 54008ffe <0f000000> 3d20c030 2f84xxxx Kernel panic - not syncing: Fatal exception in interrupt Call Trace: [c6035bf0] [c00084e4] show_stack+0x3c/0x160 (unreliable) [c6035c20] [c002cf44] panic+0xa4/0x1c8 [c6035c70] [c001085c] die+0x194/0x1a0 [c6035c90] [c0010aa8] _exception+0xfc/0x108 [c6035d80] [c0013248] ret_from_except_full+0x0/0x4c--- Exception: 700 at cpufreq_notify_transition+0x20/0x128 LR = cf750gx_pll_switch_cb+0x20/0xd0 [cf750gx][c6035e40] [c02e2280] 0xc02e2280 (unreliable) [c6035e50] [ddc4b3dc] cf750gx_pll_switch_cb+0x20/0xd0 [cf750gx] [c6035e60] [c004d7ac] notifier_call_chain+0x60/0xb0 [c6035e80] [ddc361c4] pllif_i_switch_PLLs+0xa0/0x140 [pll_if] [c6035e90] [ddc365fc] pllif_i_timer_f+0x4c/0x6c [pll_if] [c6035ea0] [c004bb24] __run_hrtimer+0x44/0xb8 [c6035eb0] [c004c1f8] hrtimer_interrupt+0x10c/0x388 [c6035f30] [c001014c] timer_interrupt+0x13c/0x19c [c6035f40] [c0013294] ret_from_except+0x0/0x14--- Exception: 901 at 0x1000c694 LR = 0x1000f3e4Rebooting in 180 seconds.._ What are exception 700 & 901?
700 is a program check (illegal instruction or BUG_ON() statement) 900 is decrementer (aka timer) interrupt.
The 0x1000c694 address looks fishy?
That's userspace. So you took a timer interrupt, which got into hrtimer, and something you did caused cpufreq_notify_transition to crash, probably with a BUG_ON (which you can probably see above what you pasted, unless you don't have access to that part of the backtrace). Cheers, Ben.
Thanks! kevin _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev