From: Michael Ellerman <mpe@ellerman.id.au>
To: Guenter Roeck <linux@roeck-us.net>,
Christophe Leroy <christophe.leroy@c-s.fr>
Cc: linux-kernel@vger.kernel.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
linuxppc-dev@lists.ozlabs.org, Paul Mackerras <paulus@samba.org>
Subject: Re: Traceback due to 'powerpc/mm: Fix kernel RAM protection...' when running ppc image in qemu
Date: Wed, 20 Sep 2017 13:05:48 +1000 [thread overview]
Message-ID: <8760ce9iib.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <20170919182459.GA7933@roeck-us.net>
Guenter Roeck <linux@roeck-us.net> writes:
> Hi,
>
> I see a the following traceback when running an SMP image based on
> 85xx/mpc85xx_cds_defconfig in qemu.
>
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1 at kernel/smp.c:416 smp_call_function_many+0xcc/0x2fc
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.0-rc1-00009-g0666f56 #1
> task: cf830000 task.stack: cf82e000
> NIP: c00a93c8 LR: c00a9634 CTR: 00000001
> REGS: cf82fde0 TRAP: 0700 Not tainted (4.14.0-rc1-00009-g0666f56)
> MSR: 00021000 <CE,ME> CR: 24000082 XER: 00000000
>
> GPR00: c00a9634 cf82fe90 cf830000 c050ad3c c0015a54 00000000 00000001 00000001
> GPR08: 00000001 00000000 00000000 cf82e000 24000084 00000000 c0003150 00000000
> GPR16: 00000000 00000000 00000000 00000000 00000000 00000001 00000000 c0510000
> GPR24: 00000000 c0015a54 00000000 c050ad3c c051823c c050ad3c 00000025 00000000
> NIP [c00a93c8] smp_call_function_many+0xcc/0x2fc
> LR [c00a9634] smp_call_function+0x3c/0x50
> Call Trace:
> [cf82fe90] [00000010] 0x10 (unreliable)
> [cf82fed0] [c00a9634] smp_call_function+0x3c/0x50
> [cf82fee0] [c0015d2c] flush_tlb_kernel_range+0x20/0x38
> [cf82fef0] [c001524c] mark_initmem_nx+0x154/0x16c
> [cf82ff20] [c001484c] free_initmem+0x20/0x4c
> [cf82ff30] [c000316c] kernel_init+0x1c/0x108
> [cf82ff40] [c000f3a8] ret_from_kernel_thread+0x5c/0x64
> Instruction dump:
> 7c0803a6 7d808120 38210040 4e800020 3d20c052 812981a0 2f890000 40beffac
> 3d20c051 8929ac64 2f890000 40beff9c <0fe00000> 4bffff94 7fc3f378 7f64db78
> ---[ end trace 7da7bdcf8b15ddb3 ]---
Thanks.
I guess the system still runs OK otherwise, you're just seeing the warning?
> A complete log is available at:
> http://kerneltests.org/builders/qemu-ppc-master/builds/814/steps/qemubuildcommand/logs/stdio
>
> Bisect points to commit 3184cc4b6f6a1dc0 ("powerpc/mm: Fix kernel RAM protection
> after freeing unused memory on PPC32"). Bisect log is attached. A quick look
> suggests that mark_initmem_nx() is called with interrupts disabled, which
> triggers the traceback.
Hmm. Yes the MSR says you have interrupts disabled (EE missing).
But I don't see why. start_kernel() did local_irq_enable(), so I don't
understand why we got to mark_initmem_nx() with them disabled. I'll hope
that Christophe has some idea.
cheers
next prev parent reply other threads:[~2017-09-20 3:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-19 18:24 Guenter Roeck
2017-09-20 3:05 ` Michael Ellerman [this message]
2017-09-20 3:45 ` Guenter Roeck
2017-09-21 18:44 ` Christophe LEROY
2017-09-24 16:05 ` Guenter Roeck
2017-09-25 6:36 ` Christophe LEROY
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