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[83.51.162.1]) by smtp.gmail.com with ESMTPSA id j16sm4834836ejn.77.2020.07.01.10.37.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 01 Jul 2020 10:37:45 -0700 (PDT) Subject: Re: [PATCH v4 01/40] hw/isa: check for current_cpu before generating IRQ From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= To: =?UTF-8?Q?Alex_Benn=c3=a9e?= References: <20200701135652.1366-1-alex.bennee@linaro.org> <20200701135652.1366-2-alex.bennee@linaro.org> <85314d31-813a-8c20-7522-5186d5f31884@redhat.com> <87pn9fqjcd.fsf@linaro.org> <838d4d01-cd9e-d74a-5cd2-b23644172c9f@redhat.com> <87k0znqi03.fsf@linaro.org> Autocrypt: addr=philmd@redhat.com; keydata= mQINBDXML8YBEADXCtUkDBKQvNsQA7sDpw6YLE/1tKHwm24A1au9Hfy/OFmkpzo+MD+dYc+7 bvnqWAeGweq2SDq8zbzFZ1gJBd6+e5v1a/UrTxvwBk51yEkadrpRbi+r2bDpTJwXc/uEtYAB GvsTZMtiQVA4kRID1KCdgLa3zztPLCj5H1VZhqZsiGvXa/nMIlhvacRXdbgllPPJ72cLUkXf z1Zu4AkEKpccZaJspmLWGSzGu6UTZ7UfVeR2Hcc2KI9oZB1qthmZ1+PZyGZ/Dy+z+zklC0xl XIpQPmnfy9+/1hj1LzJ+pe3HzEodtlVA+rdttSvA6nmHKIt8Ul6b/h1DFTmUT1lN1WbAGxmg CH1O26cz5nTrzdjoqC/b8PpZiT0kO5MKKgiu5S4PRIxW2+RA4H9nq7nztNZ1Y39bDpzwE5Sp bDHzd5owmLxMLZAINtCtQuRbSOcMjZlg4zohA9TQP9krGIk+qTR+H4CV22sWldSkVtsoTaA2 qNeSJhfHQY0TyQvFbqRsSNIe2gTDzzEQ8itsmdHHE/yzhcCVvlUzXhAT6pIN0OT+cdsTTfif MIcDboys92auTuJ7U+4jWF1+WUaJ8gDL69ThAsu7mGDBbm80P3vvUZ4fQM14NkxOnuGRrJxO qjWNJ2ZUxgyHAh5TCxMLKWZoL5hpnvx3dF3Ti9HW2dsUUWICSQARAQABtDJQaGlsaXBwZSBN YXRoaWV1LURhdWTDqSAoUGhpbCkgPHBoaWxtZEByZWRoYXQuY29tPokCVQQTAQgAPwIbDwYL CQgHAwIGFQgCCQoLBBYCAwECHgECF4AWIQSJweePYB7obIZ0lcuio/1u3q3A3gUCXsfWwAUJ KtymWgAKCRCio/1u3q3A3ircD/9Vjh3aFNJ3uF3hddeoFg1H038wZr/xi8/rX27M1Vj2j9VH 0B8Olp4KUQw/hyO6kUxqkoojmzRpmzvlpZ0cUiZJo2bQIWnvScyHxFCv33kHe+YEIqoJlaQc JfKYlbCoubz+02E2A6bFD9+BvCY0LBbEj5POwyKGiDMjHKCGuzSuDRbCn0Mz4kCa7nFMF5Jv piC+JemRdiBd6102ThqgIsyGEBXuf1sy0QIVyXgaqr9O2b/0VoXpQId7yY7OJuYYxs7kQoXI 6WzSMpmuXGkmfxOgbc/L6YbzB0JOriX0iRClxu4dEUg8Bs2pNnr6huY2Ft+qb41RzCJvvMyu gS32LfN0bTZ6Qm2A8ayMtUQgnwZDSO23OKgQWZVglGliY3ezHZ6lVwC24Vjkmq/2yBSLakZE 6DZUjZzCW1nvtRK05ebyK6tofRsx8xB8pL/kcBb9nCuh70aLR+5cmE41X4O+MVJbwfP5s/RW 9BFSL3qgXuXso/3XuWTQjJJGgKhB6xXjMmb1J4q/h5IuVV4juv1Fem9sfmyrh+Wi5V1IzKI7 RPJ3KVb937eBgSENk53P0gUorwzUcO+ASEo3Z1cBKkJSPigDbeEjVfXQMzNt0oDRzpQqH2vp apo2jHnidWt8BsckuWZpxcZ9+/9obQ55DyVQHGiTN39hkETy3Emdnz1JVHTU0Q== Message-ID: Date: Wed, 1 Jul 2020 19:37:43 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=philmd@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=philmd@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/01 00:56:58 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: fam@euphon.net, berrange@redhat.com, "Michael S. Tsirkin" , Bug 1878645 <1878645@bugs.launchpad.net>, richard.henderson@linaro.org, qemu-devel@nongnu.org, cota@braap.org, Paolo Bonzini , aurelien@aurel32.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 7/1/20 7:34 PM, Philippe Mathieu-Daudé wrote: > +Paolo > > On 7/1/20 7:09 PM, Alex Bennée wrote: >> Philippe Mathieu-Daudé writes: >>> On 7/1/20 6:40 PM, Alex Bennée wrote: >>>> Philippe Mathieu-Daudé writes: >>>> >>>>> On 7/1/20 3:56 PM, Alex Bennée wrote: >>>>>> It's possible to trigger this function from qtest/monitor at which >>>>>> point current_cpu won't point at the right place. Check it and >>>>>> fall back to first_cpu if it's NULL. >>>>>> >>>>>> Signed-off-by: Alex Bennée >>>>>> Cc: Bug 1878645 <1878645@bugs.launchpad.net> >>>>>> --- >>>>>> hw/isa/lpc_ich9.c | 2 +- >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c >>>>>> index cd6e169d47a..791c878eb0b 100644 >>>>>> --- a/hw/isa/lpc_ich9.c >>>>>> +++ b/hw/isa/lpc_ich9.c >>>>>> @@ -439,7 +439,7 @@ static void ich9_apm_ctrl_changed(uint32_t val, void *arg) >>>>>> cpu_interrupt(cs, CPU_INTERRUPT_SMI); >>>>>> } >>>>>> } else { >>>>>> - cpu_interrupt(current_cpu, CPU_INTERRUPT_SMI); >>>>>> + cpu_interrupt(current_cpu ? current_cpu : first_cpu, CPU_INTERRUPT_SMI); >>>>> >>>>> I'm not sure this change anything, as first_cpu is NULL when using >>>>> qtest accelerator or none-machine, see 508b4ecc39 ("gdbstub.c: fix >>>>> GDB connection segfault caused by empty machines"). >>>> >>>> Good point - anyway feel free to ignore - it shouldn't have been in this >>>> series. It was just some random experimentation I was doing when looking >>>> at that bug. >>> >>> See commit c781a2cc42 ("hw/i386/vmport: Allow QTest use without >>> crashing") for a similar approach, but here I was thinking about >>> a more generic fix, not very intrusive: >>> >>> -- >8 -- >>> diff --git a/hw/isa/apm.c b/hw/isa/apm.c >>> index bce266b957..809afeb3e4 100644 >>> --- a/hw/isa/apm.c >>> +++ b/hw/isa/apm.c >>> @@ -40,7 +40,7 @@ static void apm_ioport_writeb(void *opaque, hwaddr >>> addr, uint64_t val, >>> if (addr == 0) { >>> apm->apmc = val; >>> >>> - if (apm->callback) { >>> + if (apm->callback && !qtest_enabled()) { >>> (apm->callback)(val, apm->arg); >>> } >> >> But the other failure mode reported on the bug thread was via the >> monitor - so I'm not sure just checking for qtest catches that. > > Ah indeed. > > in exec.c: > > /* current CPU in the current thread. It is only valid inside > cpu_exec() */ > __thread CPUState *current_cpu; > > Maybe we shouldn't use current_cpu out of exec.c... I meant, out of cpu_exec(), a cpu thread. Here we access it from an I/O thread. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57C1BC433DF for ; Wed, 1 Jul 2020 17:46:50 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2E80220781 for ; Wed, 1 Jul 2020 17:46:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E80220781 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45866 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jqgor-0004rq-FV for qemu-devel@archiver.kernel.org; Wed, 01 Jul 2020 13:46:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35638) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqgnu-0003rK-UU for qemu-devel@nongnu.org; Wed, 01 Jul 2020 13:45:50 -0400 Received: from indium.canonical.com ([91.189.90.7]:37618) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jqgns-0005mQ-NG for qemu-devel@nongnu.org; Wed, 01 Jul 2020 13:45:50 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1jqgnp-0001tC-Jr for ; Wed, 01 Jul 2020 17:45:45 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id 0E1882E8129 for ; Wed, 1 Jul 2020 17:45:44 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 01 Jul 2020 17:37:43 -0000 From: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= <1878645@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=New; importance=Undecided; assignee=None; X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: a1xndr ajbennee philmd X-Launchpad-Bug-Reporter: Alexander Bulekov (a1xndr) X-Launchpad-Bug-Modifier: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9_=28philmd?= =?utf-8?q?=29?= References: <158947246472.30762.752698283456022174.malonedeb@chaenomeles.canonical.com> <20200701135652.1366-2-alex.bennee@linaro.org> <85314d31-813a-8c20-7522-5186d5f31884@redhat.com> <87pn9fqjcd.fsf@linaro.org> <838d4d01-cd9e-d74a-5cd2-b23644172c9f@redhat.com> <87k0znqi03.fsf@linaro.org> Message-ID: Subject: [Bug 1878645] Re: [PATCH v4 01/40] hw/isa: check for current_cpu before generating IRQ X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="1cbd0aa39df153c901321817f9b57cf3f232b507"; Instance="production-secrets-lazr.conf" X-Launchpad-Hash: a120af195b7e853c78be9e9fcbae3a433a3dc45a Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/01 10:05:42 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -58 X-Spam_score: -5.9 X-Spam_bar: ----- X-Spam_report: (-5.9 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1878645 <1878645@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20200701173743.JJmINFCnkhX5lNBeWopM53zVoot9MGmqPH7vzzA7rZc@z> On 7/1/20 7:34 PM, Philippe Mathieu-Daud=C3=A9 wrote: > +Paolo > = > On 7/1/20 7:09 PM, Alex Benn=C3=A9e wrote: >> Philippe Mathieu-Daud=C3=A9 writes: >>> On 7/1/20 6:40 PM, Alex Benn=C3=A9e wrote: >>>> Philippe Mathieu-Daud=C3=A9 writes: >>>> >>>>> On 7/1/20 3:56 PM, Alex Benn=C3=A9e wrote: >>>>>> It's possible to trigger this function from qtest/monitor at which >>>>>> point current_cpu won't point at the right place. Check it and >>>>>> fall back to first_cpu if it's NULL. >>>>>> >>>>>> Signed-off-by: Alex Benn=C3=A9e >>>>>> Cc: Bug 1878645 <1878645@bugs.launchpad.net> >>>>>> --- >>>>>> hw/isa/lpc_ich9.c | 2 +- >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c >>>>>> index cd6e169d47a..791c878eb0b 100644 >>>>>> --- a/hw/isa/lpc_ich9.c >>>>>> +++ b/hw/isa/lpc_ich9.c >>>>>> @@ -439,7 +439,7 @@ static void ich9_apm_ctrl_changed(uint32_t val, = void *arg) >>>>>> cpu_interrupt(cs, CPU_INTERRUPT_SMI); >>>>>> } >>>>>> } else { >>>>>> - cpu_interrupt(current_cpu, CPU_INTERRUPT_SMI); >>>>>> + cpu_interrupt(current_cpu ? current_cpu : first_cpu, CP= U_INTERRUPT_SMI); >>>>> >>>>> I'm not sure this change anything, as first_cpu is NULL when using >>>>> qtest accelerator or none-machine, see 508b4ecc39 ("gdbstub.c: fix >>>>> GDB connection segfault caused by empty machines"). >>>> >>>> Good point - anyway feel free to ignore - it shouldn't have been in th= is >>>> series. It was just some random experimentation I was doing when looki= ng >>>> at that bug. >>> >>> See commit c781a2cc42 ("hw/i386/vmport: Allow QTest use without >>> crashing") for a similar approach, but here I was thinking about >>> a more generic fix, not very intrusive: >>> >>> -- >8 -- >>> diff --git a/hw/isa/apm.c b/hw/isa/apm.c >>> index bce266b957..809afeb3e4 100644 >>> --- a/hw/isa/apm.c >>> +++ b/hw/isa/apm.c >>> @@ -40,7 +40,7 @@ static void apm_ioport_writeb(void *opaque, hwaddr >>> addr, uint64_t val, >>> if (addr =3D=3D 0) { >>> apm->apmc =3D val; >>> >>> - if (apm->callback) { >>> + if (apm->callback && !qtest_enabled()) { >>> (apm->callback)(val, apm->arg); >>> } >> >> But the other failure mode reported on the bug thread was via the >> monitor - so I'm not sure just checking for qtest catches that. > = > Ah indeed. > = > in exec.c: > = > /* current CPU in the current thread. It is only valid inside > cpu_exec() */ > __thread CPUState *current_cpu; > = > Maybe we shouldn't use current_cpu out of exec.c... I meant, out of cpu_exec(), a cpu thread. Here we access it from an I/O thread. -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1878645 Title: null-ptr dereference in ich9_apm_ctrl_changed Status in QEMU: New Bug description: Hello, While fuzzing, I found an input which triggers a NULL pointer dereference= in tcg_handle_interrupt. It seems the culprint is a "cpu" pointer - maybe th= is bug is specific to QTest? =3D=3D23862=3D=3DERROR: AddressSanitizer: SEGV on unknown address 0x00000= 00000b4 (pc 0x55b9dc7c9dce bp 0x7ffc346a0900 sp 0x7ffc346a0880 T0) =3D=3D23862=3D=3DThe signal is caused by a READ memory access. =3D=3D23862=3D=3DHint: address points to the zero page. #0 0x55b9dc7c9dce in tcg_handle_interrupt /home/alxndr/Development/qe= mu/accel/tcg/tcg-all.c:57:21 #1 0x55b9dc904799 in cpu_interrupt /home/alxndr/Development/qemu/incl= ude/hw/core/cpu.h:872:5 #2 0x55b9dc9085e8 in ich9_apm_ctrl_changed /home/alxndr/Development/q= emu/hw/isa/lpc_ich9.c:442:13 #3 0x55b9dd19cdc8 in apm_ioport_writeb /home/alxndr/Development/qemu/= hw/isa/apm.c:50:13 #4 0x55b9dc73f8b4 in memory_region_write_accessor /home/alxndr/Develo= pment/qemu/memory.c:483:5 #5 0x55b9dc73f289 in access_with_adjusted_size /home/alxndr/Developme= nt/qemu/memory.c:544:18 #6 0x55b9dc73ddf5 in memory_region_dispatch_write /home/alxndr/Develo= pment/qemu/memory.c:1476:16 #7 0x55b9dc577bf3 in flatview_write_continue /home/alxndr/Development= /qemu/exec.c:3137:23 #8 0x55b9dc567ad8 in flatview_write /home/alxndr/Development/qemu/exe= c.c:3177:14 #9 0x55b9dc567608 in address_space_write /home/alxndr/Development/qem= u/exec.c:3268:18 #10 0x55b9dc723fe7 in cpu_outb /home/alxndr/Development/qemu/ioport.c= :60:5 #11 0x55b9dc72d3c0 in qtest_process_command /home/alxndr/Development/= qemu/qtest.c:392:13 #12 0x55b9dc72b186 in qtest_process_inbuf /home/alxndr/Development/qe= mu/qtest.c:710:9 #13 0x55b9dc72a8b3 in qtest_read /home/alxndr/Development/qemu/qtest.= c:722:5 #14 0x55b9ddc6e60b in qemu_chr_be_write_impl /home/alxndr/Development= /qemu/chardev/char.c:183:9 #15 0x55b9ddc6e75a in qemu_chr_be_write /home/alxndr/Development/qemu= /chardev/char.c:195:9 #16 0x55b9ddc77979 in fd_chr_read /home/alxndr/Development/qemu/chard= ev/char-fd.c:68:9 #17 0x55b9ddcff0e9 in qio_channel_fd_source_dispatch /home/alxndr/Dev= elopment/qemu/io/channel-watch.c:84:12 #18 0x7f7161eac897 in g_main_context_dispatch (/usr/lib/x86_64-linux-= gnu/libglib-2.0.so.0+0x4e897) #19 0x55b9ddebcb84 in glib_pollfds_poll /home/alxndr/Development/qemu= /util/main-loop.c:219:9 #20 0x55b9ddebb57d in os_host_main_loop_wait /home/alxndr/Development= /qemu/util/main-loop.c:242:5 #21 0x55b9ddebb176 in main_loop_wait /home/alxndr/Development/qemu/ut= il/main-loop.c:518:11 #22 0x55b9dcb4bd1d in qemu_main_loop /home/alxndr/Development/qemu/so= ftmmu/vl.c:1664:9 #23 0x55b9ddd1629c in main /home/alxndr/Development/qemu/softmmu/main= .c:49:5 #24 0x7f7160a5ce0a in __libc_start_main /build/glibc-GwnBeO/glibc-2.3= 0/csu/../csu/libc-start.c:308:16 #25 0x55b9dc49c819 in _start (/home/alxndr/Development/qemu/build/i38= 6-softmmu/qemu-system-i386+0xc9c819) = I can reproduce this in qemu 5.0 built with AddressSanitizer using these = qtest commands: cat << EOF | ./qemu-system-i386 \ -qtest stdio -nographic -monitor none -serial none \ -M pc-q35-5.0 outl 0xcf8 0x8400f841 outl 0xcfc 0xaa215d6d outl 0x6d30 0x2ef8ffbe outb 0xb2 0x20 EOF Please let me know if I can provide any further info. -Alex To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1878645/+subscriptions