From: Christophe Leroy <christophe.leroy@c-s.fr> To: Michael Ellerman <mpe@ellerman.id.au>, Dan Carpenter <dan.carpenter@oracle.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Kim Phillips <kim.phillips@arm.com> Cc: linuxppc-dev@lists.ozlabs.org, kernel-janitors@vger.kernel.org, Paul Mackerras <paulus@samba.org> Subject: Re: [PATCH] powerpc/ipic: Fix a bounds check in ipic_set_priority() Date: Mon, 10 Dec 2018 12:05:40 +0000 [thread overview] Message-ID: <9182f885-5773-d42e-20eb-26923a34e011@c-s.fr> (raw) In-Reply-To: <878t12ks3f.fsf@concordia.ellerman.id.au> Le 07/12/2018 à 03:07, Michael Ellerman a écrit : > Christophe LEROY <christophe.leroy@c-s.fr> writes: >> Le 05/12/2018 à 04:26, Michael Ellerman a écrit : >>> Hi Dan, >>> >>> Thanks for the patch. >>> >>> Dan Carpenter <dan.carpenter@oracle.com> writes: >>>> The ipic_info[] array only has 95 elements so I have made the bounds >>>> check smaller to prevent a read overflow. It was Smatch that found >>>> this issue: >>>> >>>> arch/powerpc/sysdev/ipic.c:784 ipic_set_priority() >>>> error: buffer overflow 'ipic_info' 95 <= 127 >>>> >>>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> >>>> --- >>>> I wasn't able to find any callers of this code. Maybe we removed the >>>> last one in commit b9f0f1bb2bca ("[POWERPC] Adapt ipic driver to new >>>> host_ops interface, add set_irq_type to set IRQ sense"). So perhaps we >>>> should just remove it. I'm not really comfortable doing that myself, >>>> because I don't know the code well enough and can't build test >>>> it properly. >>> >>> Hah wow, last usage removed in 2006! >>> >>> I don't see any mention of it since then, so I'll remove it. If it >>> breaks something we can put it back. >>> >>> Can smatch help us find things like this that are defined non-static but >>> never used? >>> >> >> I think we have to do that carrefully. Some of those functions might be >> used by out-of-tree boards. > > We don't keep unused code around for out-of-tree boards. > > Either the out-of-tree code should be merged upstream, or you can > maintain whatever extra functions you need as part of your out-of-tree > code base. > >> I'm thinking especially at ipic_get_mcp_status() and >> ipic_set_mcp_status(). They are used in my 832x boards's machine check >> handler to know when a machine check is a timeout from the 832x watchdog. > > Thanks for pointing them out, I'll send a patch to remove them :) Lol :) If you are doing the housework, you can remove ipic_set_highest_priority() ipic_enable_mcp() and ipic_disable_mcp() > > But seriously, why is your machine check code not in-tree, is there some > reason you can't merge it? Maybe because you haven't merged it yet allthough I sent it more than three minutes ago. :) Seriously, that was just left over with other priorities, and also because I'm not too happy about it because what I would really like is that it kills the userland app if any but don't crash the system when it is in interrupt or in idle. But due to b96672dd840f ("powerpc: Machine check interrupt is a non-maskable interrupt"), die_will_crash() doesn't work anymore. So for the time being, the patch I sent is not killing anybody, just doing an Oops for notification (note that die_will_crash() is used in the Opal machine check handler, so it probably doesn't work anymore there either). Christophe
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From: Christophe Leroy <christophe.leroy@c-s.fr> To: Michael Ellerman <mpe@ellerman.id.au>, Dan Carpenter <dan.carpenter@oracle.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Kim Phillips <kim.phillips@arm.com> Cc: linuxppc-dev@lists.ozlabs.org, kernel-janitors@vger.kernel.org, Paul Mackerras <paulus@samba.org> Subject: Re: [PATCH] powerpc/ipic: Fix a bounds check in ipic_set_priority() Date: Mon, 10 Dec 2018 13:05:40 +0100 [thread overview] Message-ID: <9182f885-5773-d42e-20eb-26923a34e011@c-s.fr> (raw) In-Reply-To: <878t12ks3f.fsf@concordia.ellerman.id.au> Le 07/12/2018 à 03:07, Michael Ellerman a écrit : > Christophe LEROY <christophe.leroy@c-s.fr> writes: >> Le 05/12/2018 à 04:26, Michael Ellerman a écrit : >>> Hi Dan, >>> >>> Thanks for the patch. >>> >>> Dan Carpenter <dan.carpenter@oracle.com> writes: >>>> The ipic_info[] array only has 95 elements so I have made the bounds >>>> check smaller to prevent a read overflow. It was Smatch that found >>>> this issue: >>>> >>>> arch/powerpc/sysdev/ipic.c:784 ipic_set_priority() >>>> error: buffer overflow 'ipic_info' 95 <= 127 >>>> >>>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> >>>> --- >>>> I wasn't able to find any callers of this code. Maybe we removed the >>>> last one in commit b9f0f1bb2bca ("[POWERPC] Adapt ipic driver to new >>>> host_ops interface, add set_irq_type to set IRQ sense"). So perhaps we >>>> should just remove it. I'm not really comfortable doing that myself, >>>> because I don't know the code well enough and can't build test >>>> it properly. >>> >>> Hah wow, last usage removed in 2006! >>> >>> I don't see any mention of it since then, so I'll remove it. If it >>> breaks something we can put it back. >>> >>> Can smatch help us find things like this that are defined non-static but >>> never used? >>> >> >> I think we have to do that carrefully. Some of those functions might be >> used by out-of-tree boards. > > We don't keep unused code around for out-of-tree boards. > > Either the out-of-tree code should be merged upstream, or you can > maintain whatever extra functions you need as part of your out-of-tree > code base. > >> I'm thinking especially at ipic_get_mcp_status() and >> ipic_set_mcp_status(). They are used in my 832x boards's machine check >> handler to know when a machine check is a timeout from the 832x watchdog. > > Thanks for pointing them out, I'll send a patch to remove them :) Lol :) If you are doing the housework, you can remove ipic_set_highest_priority() ipic_enable_mcp() and ipic_disable_mcp() > > But seriously, why is your machine check code not in-tree, is there some > reason you can't merge it? Maybe because you haven't merged it yet allthough I sent it more than three minutes ago. :) Seriously, that was just left over with other priorities, and also because I'm not too happy about it because what I would really like is that it kills the userland app if any but don't crash the system when it is in interrupt or in idle. But due to b96672dd840f ("powerpc: Machine check interrupt is a non-maskable interrupt"), die_will_crash() doesn't work anymore. So for the time being, the patch I sent is not killing anybody, just doing an Oops for notification (note that die_will_crash() is used in the Opal machine check handler, so it probably doesn't work anymore there either). Christophe
next prev parent reply other threads:[~2018-12-10 12:05 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-12-03 14:48 [PATCH] powerpc/ipic: Fix a bounds check in ipic_set_priority() Dan Carpenter 2018-12-03 14:48 ` Dan Carpenter 2018-12-05 3:26 ` Michael Ellerman 2018-12-05 3:26 ` Michael Ellerman 2018-12-05 8:11 ` Julia Lawall 2018-12-05 8:11 ` Julia Lawall 2018-12-05 12:04 ` Michael Ellerman 2018-12-05 12:04 ` Michael Ellerman 2018-12-05 12:06 ` Julia Lawall 2018-12-05 12:06 ` Julia Lawall 2018-12-06 7:18 ` Christophe LEROY 2018-12-06 7:18 ` Christophe LEROY 2018-12-06 8:12 ` Julia Lawall 2018-12-06 8:12 ` Julia Lawall 2018-12-11 14:26 ` Dan Carpenter 2018-12-11 14:26 ` Dan Carpenter 2018-12-07 2:07 ` Michael Ellerman 2018-12-07 2:07 ` Michael Ellerman 2018-12-10 12:05 ` Christophe Leroy [this message] 2018-12-10 12:05 ` Christophe Leroy 2018-12-06 9:34 ` Dan Carpenter 2018-12-06 9:34 ` Dan Carpenter
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