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From:   Michael Ellerman <patch-notifications@ellerman.id.au>
To:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        fthain@linux-m68k.org, npiggin@gmail.com,
        Michael Ellerman <mpe@ellerman.id.au>, userm57@yahoo.com,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Paul Mackerras <paulus@samba.org>
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
In-Reply-To: <c17d234f4927d39a1d7100864a8e1145323d33a0.1628611927.git.christophe.leroy@csgroup.eu>
References: <c17d234f4927d39a1d7100864a8e1145323d33a0.1628611927.git.christophe.leroy@csgroup.eu>
Subject: Re: [PATCH] powerpc/interrupt: Fix OOPS by not calling do_IRQ() from timer_interrupt()
Message-Id: <162885586792.2317031.17954514979013171970.b4-ty@ellerman.id.au>
Date:   Fri, 13 Aug 2021 21:57:47 +1000
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On Tue, 10 Aug 2021 16:13:16 +0000 (UTC), Christophe Leroy wrote:
> An interrupt handler shall not be called from another interrupt
> handler otherwise this leads to problems like the following:
> 
> 	Kernel attempted to write user page (afd4fa84) - exploit attempt? (uid: 1000)
> 	------------[ cut here ]------------
> 	Bug: Write fault blocked by KUAP!
> 	WARNING: CPU: 0 PID: 1617 at arch/powerpc/mm/fault.c:230 do_page_fault+0x484/0x720
> 	Modules linked in:
> 	CPU: 0 PID: 1617 Comm: sshd Tainted: G        W         5.13.0-pmac-00010-g8393422eb77 #7
> 	NIP:  c001b77c LR: c001b77c CTR: 00000000
> 	REGS: cb9e5bc0 TRAP: 0700   Tainted: G        W          (5.13.0-pmac-00010-g8393422eb77)
> 	MSR:  00021032 <ME,IR,DR,RI>  CR: 24942424  XER: 00000000
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/interrupt: Fix OOPS by not calling do_IRQ() from timer_interrupt()
      https://git.kernel.org/powerpc/c/98694166c27d473c36b434bd3572934c2f2a16ab

cheers