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From: Paolo Bonzini <pbonzini@redhat.com>
To: Markus Armbruster <armbru@redhat.com>,
	Igor Mammedov <imammedo@redhat.com>
Cc: qemu-devel@nongnu.org, Eduardo Habkost <ehabkost@redhat.com>,
	Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH v3 20/26] x86: Fix x86_cpu_new() error handling
Date: Thu, 2 Jul 2020 10:59:43 +0200	[thread overview]
Message-ID: <3f549d5f-18a2-886d-193c-052865fefff3@redhat.com> (raw)
In-Reply-To: <87h7uq7c42.fsf@dusky.pond.sub.org>

On 02/07/20 06:51, Markus Armbruster wrote:
> Igor, Paolo, you showed me the error in v2.  Could you have a look at
> this revision?
> 
> Markus Armbruster <armbru@redhat.com> writes:
> 
>> The Error ** argument must be NULL, &error_abort, &error_fatal, or a
>> pointer to a variable containing NULL.  Passing an argument of the
>> latter kind twice without clearing it in between is wrong: if the
>> first call sets an error, it no longer points to NULL for the second
>> call.
>>
>> x86_cpu_new() is wrong that way: it passes &local_err to
>> object_property_set_uint() without checking it, and then to
>> qdev_realize().  If both fail, we'll trip error_setv()'s assertion.
>> To assess the bug's impact, we'd need to figure out how to make both
>> calls fail.  Too much work for ignorant me, sorry.
>>
>> Fix by checking for failure right away.
>>
>> Cc: Igor Mammedov <imammedo@redhat.com>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Richard Henderson <rth@twiddle.net>
>> Cc: Eduardo Habkost <ehabkost@redhat.com>
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> ---
>>  hw/i386/x86.c | 8 +++++---
>>  1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/i386/x86.c b/hw/i386/x86.c
>> index 34229b45c7..93f7371a56 100644
>> --- a/hw/i386/x86.c
>> +++ b/hw/i386/x86.c
>> @@ -118,14 +118,16 @@ uint32_t x86_cpu_apic_id_from_index(X86MachineState *x86ms,
>>  
>>  void x86_cpu_new(X86MachineState *x86ms, int64_t apic_id, Error **errp)
>>  {
>> -    Object *cpu = NULL;
>>      Error *local_err = NULL;
>> -
>> -    cpu = object_new(MACHINE(x86ms)->cpu_type);
>> +    Object *cpu = object_new(MACHINE(x86ms)->cpu_type);
>>  
>>      object_property_set_uint(cpu, apic_id, "apic-id", &local_err);
>> +    if (local_err) {
>> +        goto out;
>> +    }
>>      qdev_realize(DEVICE(cpu), NULL, &local_err);
>>  
>> +out:
>>      object_unref(cpu);
>>      error_propagate(errp, local_err);
>>  }
> 

Yes, this looks good.  Thanks!

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Paolo



  reply	other threads:[~2020-07-02  9:00 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-30  9:03 [PATCH v3 00/26] Error handling fixes & cleanups Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 01/26] net/virtio: Fix failover_replug_primary() return value regression Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 02/26] pci: Delete useless error_propagate() Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 03/26] Clean up some calls to ignore Error objects the right way Markus Armbruster
2020-06-30  9:21   ` Daniel P. Berrangé
2020-06-30  9:03 ` [PATCH v3 04/26] tests: Use &error_abort where appropriate Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 05/26] tests: Use error_free_or_abort() " Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 06/26] usb/dev-mtp: Fix Error double free after inotify failure Markus Armbruster
2020-06-30  9:20   ` Daniel P. Berrangé
2020-06-30  9:03 ` [PATCH v3 07/26] spapr: Plug minor memory leak in spapr_machine_init() Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 08/26] qga: Plug unlikely memory leak in guest-set-memory-blocks Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 09/26] sd/milkymist-memcard: Plug minor memory leak in realize Markus Armbruster
2020-06-30  9:10   ` Philippe Mathieu-Daudé
2020-06-30  9:03 ` [PATCH v3 10/26] test-util-filemonitor: Plug unlikely memory leak Markus Armbruster
2020-06-30  9:20   ` Daniel P. Berrangé
2020-06-30  9:03 ` [PATCH v3 11/26] vnc: Plug minor memory leak in vnc_display_open() Markus Armbruster
2020-06-30  9:19   ` Daniel P. Berrangé
2020-06-30  9:03 ` [PATCH v3 12/26] aspeed: Clean up roundabout error propagation Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 13/26] qdev: Drop qbus_set_bus_hotplug_handler() parameter @errp Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 14/26] qdev: Drop qbus_set_hotplug_handler() " Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 15/26] hw: Fix error API violation around object_property_set_link() Markus Armbruster
2020-06-30 20:04   ` Mark Cave-Ayland
2020-06-30  9:03 ` [PATCH v3 16/26] hw/arm: Drop useless object_property_set_link() error handling Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 17/26] riscv/sifive_u: Fix sifive_u_soc_realize() error API violations Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 18/26] riscv_hart: Fix riscv_harts_realize() " Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 19/26] mips/cps: Fix mips_cps_realize() " Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 20/26] x86: Fix x86_cpu_new() error handling Markus Armbruster
2020-07-02  4:51   ` Markus Armbruster
2020-07-02  8:59     ` Paolo Bonzini [this message]
2020-06-30  9:03 ` [PATCH v3 21/26] amd_iommu: Fix amdvi_realize() error API violation Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 22/26] arm/stm32f205 arm/stm32f405: Fix realize " Markus Armbruster
2020-06-30  9:14   ` Philippe Mathieu-Daudé
2020-07-01  7:24     ` Markus Armbruster
2020-06-30  9:03 ` [PATCH v3 23/26] aspeed: " Markus Armbruster
2020-06-30  9:15   ` Philippe Mathieu-Daudé
2020-06-30  9:03 ` [PATCH v3 24/26] hw/arm/armsse: Fix armsse_realize() " Markus Armbruster
2020-06-30  9:11   ` Philippe Mathieu-Daudé
2020-06-30  9:03 ` [PATCH v3 25/26] arm/{bcm2835, fsl-imx25, fsl-imx6}: Fix realize error API violations Markus Armbruster
2020-06-30  9:12   ` [PATCH v3 25/26] arm/{bcm2835,fsl-imx25,fsl-imx6}: " Philippe Mathieu-Daudé
2020-06-30  9:03 ` [PATCH v3 26/26] migration/rdma: Plug memory leaks in qemu_rdma_registration_stop() Markus Armbruster
2020-06-30  9:33   ` Dr. David Alan Gilbert

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