From: Paolo Bonzini <pbonzini@redhat.com>
To: Alexander Bulekov <alxndr@bu.edu>
Cc: "bsd@redhat.com" <bsd@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [PATCH v8 13/21] main: keep rcu_atfork callback enabled for qtest
Date: Thu, 30 Jan 2020 19:14:15 +0100 [thread overview]
Message-ID: <a374881f-b3af-eb51-9fc8-ee4d43dd7b15@redhat.com> (raw)
In-Reply-To: <20200130174246.fd4dcs7gntoyzx5i@mozz.bu.edu>
On 30/01/20 18:42, Alexander Bulekov wrote:
> With QTest, is this still a concern, since there are no CPU instructions
> involved? Sometimes the fork-server starts after some I/O has already
> occured (eg mapping BARs and setting up VQs for virtio-net). I know we
> briefly talked about threads at some point, and it seems that iothreads
> may be a concern, if any are started before fork. Other than that, since
> there is no TCG/CPU thread, are there any other threads that could be
> a concern?
> -Alex
There is a CPU thread, it just does not do MMIO. However, it may still
execute code via run_on_cpu. It's quite unlikely to have the deadlock,
but if it were possible to force an early start of the fork server (at
the point of os_daemonize() would be ideal) it would be cleaner and it
would allow reverting this patch.
This is not a NACK, just some extra info.
Paolo
next prev parent reply other threads:[~2020-01-30 18:15 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 5:34 [PATCH v8 00/21] Add virtual device fuzzing support Bulekov, Alexander
2020-01-29 5:34 ` [PATCH v8 01/21] softmmu: split off vl.c:main() into main.c Bulekov, Alexander
2020-01-30 14:39 ` Stefan Hajnoczi
2020-01-30 15:06 ` Alex Bennée
2020-01-30 17:44 ` Alexander Bulekov
2020-01-30 18:41 ` Alex Bennée
2020-02-05 14:02 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 02/21] module: check module wasn't already initialized Bulekov, Alexander
2020-01-29 5:34 ` [PATCH v8 03/21] fuzz: add FUZZ_TARGET module type Bulekov, Alexander
2020-02-05 11:28 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 04/21] qtest: add qtest_server_send abstraction Bulekov, Alexander
2020-02-05 11:30 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 05/21] libqtest: add a layer of abstraction to send/recv Bulekov, Alexander
2020-02-05 11:32 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 06/21] libqtest: make bufwrite rely on the TransportOps Bulekov, Alexander
2020-02-05 11:36 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 07/21] qtest: add in-process incoming command handler Bulekov, Alexander
2020-02-05 11:39 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 09/21] libqos: split qos-test and libqos makefile vars Bulekov, Alexander
2020-01-29 5:34 ` [PATCH v8 08/21] libqos: rename i2c_send and i2c_recv Bulekov, Alexander
2020-02-05 11:40 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 10/21] libqos: move useful qos-test funcs to qos_external Bulekov, Alexander
2020-01-29 10:03 ` Paolo Bonzini
2020-02-05 13:34 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 11/21] fuzz: add fuzzer skeleton Bulekov, Alexander
2020-02-05 11:55 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 12/21] exec: keep ram block across fork when using qtest Bulekov, Alexander
2020-02-05 13:00 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 13/21] main: keep rcu_atfork callback enabled for qtest Bulekov, Alexander
2020-01-30 14:42 ` Stefan Hajnoczi
2020-01-30 17:24 ` Paolo Bonzini
2020-01-30 17:42 ` Alexander Bulekov
2020-01-30 18:14 ` Paolo Bonzini [this message]
2020-02-05 13:58 ` Darren Kenny
2020-06-18 7:34 ` Thomas Huth
2020-06-18 15:08 ` Alexander Bulekov
2020-01-29 5:34 ` [PATCH v8 14/21] fuzz: support for fork-based fuzzing Bulekov, Alexander
2020-01-29 5:34 ` [PATCH v8 15/21] fuzz: add support for qos-assisted fuzz targets Bulekov, Alexander
2020-02-05 13:18 ` Darren Kenny
2020-02-11 16:19 ` Alexander Bulekov
2020-01-29 5:34 ` [PATCH v8 16/21] fuzz: add target/fuzz makefile rules Bulekov, Alexander
2020-01-29 5:34 ` [PATCH v8 17/21] fuzz: add configure flag --enable-fuzzing Bulekov, Alexander
2020-02-05 13:19 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 18/21] fuzz: add i440fx fuzz targets Bulekov, Alexander
2020-02-05 13:26 ` Darren Kenny
2020-02-06 14:47 ` Alexander Bulekov
2020-01-29 5:34 ` [PATCH v8 19/21] fuzz: add virtio-net fuzz target Bulekov, Alexander
2020-01-30 14:43 ` Stefan Hajnoczi
2020-02-05 13:57 ` Darren Kenny
2020-02-06 14:51 ` Alexander Bulekov
2020-01-29 5:34 ` [PATCH v8 20/21] fuzz: add virtio-scsi " Bulekov, Alexander
2020-02-05 13:31 ` Darren Kenny
2020-01-29 5:34 ` [PATCH v8 21/21] fuzz: add documentation to docs/devel/ Bulekov, Alexander
2020-02-05 13:33 ` Darren Kenny
2020-01-30 14:44 ` [PATCH v8 00/21] Add virtual device fuzzing support Stefan Hajnoczi
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