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From:   Michael Ellerman <patch-notifications@ellerman.id.au>
To:     Christophe Leroy <christophe.leroy@csgroup.eu>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paul Mackerras <paulus@samba.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
In-Reply-To: <3d5800b0bbcd7b19761b98f50421358667b45331.1635520232.git.christophe.leroy@csgroup.eu>
References: <3d5800b0bbcd7b19761b98f50421358667b45331.1635520232.git.christophe.leroy@csgroup.eu>
Subject: Re: [PATCH] powerpc/8xx: Fix Oops with STRICT_KERNEL_RWX without DEBUG_RODATA_TEST
Message-Id: <163612125412.2515705.13745636929777214451.b4-ty@ellerman.id.au>
Date:   Sat, 06 Nov 2021 01:07:34 +1100
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On Fri, 29 Oct 2021 17:10:45 +0200, Christophe Leroy wrote:
> Until now, all tests involving CONFIG_STRICT_KERNEL_RWX were done with
> DEBUG_RODATA_TEST to check the result. But now that
> CONFIG_STRICT_KERNEL_RWX is selected by default, it came without
> CONFIG_DEBUG_RODATA_TEST and led to the following Oops
> 
> [    6.830908] Freeing unused kernel image (initmem) memory: 352K
> [    6.840077] BUG: Unable to handle kernel data access on write at 0xc1285200
> [    6.846836] Faulting instruction address: 0xc0004b6c
> [    6.851745] Oops: Kernel access of bad area, sig: 11 [#1]
> [    6.857075] BE PAGE_SIZE=16K PREEMPT CMPC885
> [    6.861348] SAF3000 DIE NOTIFICATION
> [    6.864830] CPU: 0 PID: 1 Comm: swapper Not tainted 5.15.0-rc5-s3k-dev-02255-g2747d7b7916f #451
> [    6.873429] NIP:  c0004b6c LR: c0004b60 CTR: 00000000
> [    6.878419] REGS: c902be60 TRAP: 0300   Not tainted  (5.15.0-rc5-s3k-dev-02255-g2747d7b7916f)
> [    6.886852] MSR:  00009032 <EE,ME,IR,DR,RI>  CR: 53000335  XER: 8000ff40
> [    6.893564] DAR: c1285200 DSISR: 82000000
> [    6.893564] GPR00: 0c000000 c902bf20 c20f4000 08000000 00000001 04001f00 c1800000 00000035
> [    6.893564] GPR08: ff0001ff c1280000 00000002 c0004b60 00001000 00000000 c0004b1c 00000000
> [    6.893564] GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> [    6.893564] GPR24: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 c1060000
> [    6.932034] NIP [c0004b6c] kernel_init+0x50/0x138
> [    6.936682] LR [c0004b60] kernel_init+0x44/0x138
> [    6.941245] Call Trace:
> [    6.943653] [c902bf20] [c0004b60] kernel_init+0x44/0x138 (unreliable)
> [    6.950022] [c902bf30] [c001122c] ret_from_kernel_thread+0x5c/0x64
> [    6.956135] Instruction dump:
> [    6.959060] 48ffc521 48045469 4800d8cd 3d20c086 89295fa0 2c090000 41820058 480796c9
> [    6.966890] 4800e48d 3d20c128 39400002 3fe0c106 <91495200> 3bff8000 4806fa1d 481f7d75
> [    6.974902] ---[ end trace 1e397bacba4aa610 ]---
> 
> [...]

Applied to powerpc/next.

[1/1] powerpc/8xx: Fix Oops with STRICT_KERNEL_RWX without DEBUG_RODATA_TEST
      https://git.kernel.org/powerpc/c/c12ab8dbc492b992e1ea717db933cee568780c47

cheers