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Mon, 27 Apr 2020 04:09:38 -0400 X-MC-Unique: -IYAubvcOzWrSxVbvSUbKA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D1DC3107ACCA; Mon, 27 Apr 2020 08:09:36 +0000 (UTC) Received: from [10.36.110.26] (unknown [10.36.110.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1FB176063C; Mon, 27 Apr 2020 08:09:32 +0000 (UTC) To: =?UTF-8?B?546L5b+X5YWL?= , Zhike Wang , dev@openvswitch.org Cc: dev@dpdk.org, stable@dpdk.org, xiaolong.ye@intel.com References: <1584007039-12437-1-git-send-email-wangzhike@jd.com> <178ab8fa.363e.170ebb22d94.Coremail.wangzk320@163.com> From: Maxime Coquelin Autocrypt: addr=maxime.coquelin@redhat.com; keydata= mQINBFOEQQIBEADjNLYZZqghYuWv1nlLisptPJp+TSxE/KuP7x47e1Gr5/oMDJ1OKNG8rlNg kLgBQUki3voWhUbMb69ybqdMUHOl21DGCj0BTU3lXwapYXOAnsh8q6RRM+deUpasyT+Jvf3a gU35dgZcomRh5HPmKMU4KfeA38cVUebsFec1HuJAWzOb/UdtQkYyZR4rbzw8SbsOemtMtwOx YdXodneQD7KuRU9IhJKiEfipwqk2pufm2VSGl570l5ANyWMA/XADNhcEXhpkZ1Iwj3TWO7XR uH4xfvPl8nBsLo/EbEI7fbuUULcAnHfowQslPUm6/yaGv6cT5160SPXT1t8U9QDO6aTSo59N jH519JS8oeKZB1n1eLDslCfBpIpWkW8ZElGkOGWAN0vmpLfdyiqBNNyS3eGAfMkJ6b1A24un /TKc6j2QxM0QK4yZGfAxDxtvDv9LFXec8ENJYsbiR6WHRHq7wXl/n8guyh5AuBNQ3LIK44x0 KjGXP1FJkUhUuruGyZsMrDLBRHYi+hhDAgRjqHgoXi5XGETA1PAiNBNnQwMf5aubt+mE2Q5r qLNTgwSo2dpTU3+mJ3y3KlsIfoaxYI7XNsPRXGnZi4hbxmeb2NSXgdCXhX3nELUNYm4ArKBP LugOIT/zRwk0H0+RVwL2zHdMO1Tht1UOFGfOZpvuBF60jhMzbQARAQABtCxNYXhpbWUgQ29x dWVsaW4gPG1heGltZS5jb3F1ZWxpbkByZWRoYXQuY29tPokCOAQTAQIAIgUCV3u/5QIbAwYL CQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQyjiNKEaHD4ma2g/+P+Hg9WkONPaY1J4AR7Uf kBneosS4NO3CRy0x4WYmUSLYMLx1I3VH6SVjqZ6uBoYy6Fs6TbF6SHNc7QbB6Qjo3neqnQR1 71Ua1MFvIob8vUEl3jAR/+oaE1UJKrxjWztpppQTukIk4oJOmXbL0nj3d8dA2QgHdTyttZ1H xzZJWWz6vqxCrUqHU7RSH9iWg9R2iuTzii4/vk1oi4Qz7y/q8ONOq6ffOy/t5xSZOMtZCspu Mll2Szzpc/trFO0pLH4LZZfz/nXh2uuUbk8qRIJBIjZH3ZQfACffgfNefLe2PxMqJZ8mFJXc RQO0ONZvwoOoHL6CcnFZp2i0P5ddduzwPdGsPq1bnIXnZqJSl3dUfh3xG5ArkliZ/++zGF1O wvpGvpIuOgLqjyCNNRoR7cP7y8F24gWE/HqJBXs1qzdj/5Hr68NVPV1Tu/l2D1KMOcL5sOrz 2jLXauqDWn1Okk9hkXAP7+0Cmi6QwAPuBT3i6t2e8UdtMtCE4sLesWS/XohnSFFscZR6Vaf3 gKdWiJ/fW64L6b9gjkWtHd4jAJBAIAx1JM6xcA1xMbAFsD8gA2oDBWogHGYcScY/4riDNKXi lw92d6IEHnSf6y7KJCKq8F+Jrj2BwRJiFKTJ6ChbOpyyR6nGTckzsLgday2KxBIyuh4w+hMq TGDSp2rmWGJjASq5Ag0EVPSbkwEQAMkaNc084Qvql+XW+wcUIY+Dn9A2D1gMr2BVwdSfVDN7 0ZYxo9PvSkzh6eQmnZNQtl8WSHl3VG3IEDQzsMQ2ftZn2sxjcCadexrQQv3Lu60Tgj7YVYRM H+fLYt9W5YuWduJ+FPLbjIKynBf6JCRMWr75QAOhhhaI0tsie3eDsKQBA0w7WCuPiZiheJaL 4MDe9hcH4rM3ybnRW7K2dLszWNhHVoYSFlZGYh+MGpuODeQKDS035+4H2rEWgg+iaOwqD7bg CQXwTZ1kSrm8NxIRVD3MBtzp9SZdUHLfmBl/tLVwDSZvHZhhvJHC6Lj6VL4jPXF5K2+Nn/Su CQmEBisOmwnXZhhu8ulAZ7S2tcl94DCo60ReheDoPBU8PR2TLg8rS5f9w6mLYarvQWL7cDtT d2eX3Z6TggfNINr/RTFrrAd7NHl5h3OnlXj7PQ1f0kfufduOeCQddJN4gsQfxo/qvWVB7PaE 1WTIggPmWS+Xxijk7xG6x9McTdmGhYaPZBpAxewK8ypl5+yubVsE9yOOhKMVo9DoVCjh5To5 aph7CQWfQsV7cd9PfSJjI2lXI0dhEXhQ7lRCFpf3V3mD6CyrhpcJpV6XVGjxJvGUale7+IOp sQIbPKUHpB2F+ZUPWds9yyVxGwDxD8WLqKKy0WLIjkkSsOb9UBNzgRyzrEC9lgQ/ABEBAAGJ Ah8EGAECAAkFAlT0m5MCGwwACgkQyjiNKEaHD4nU8hAAtt0xFJAy0sOWqSmyxTc7FUcX+pbD KVyPlpl6urKKMk1XtVMUPuae/+UwvIt0urk1mXi6DnrAN50TmQqvdjcPTQ6uoZ8zjgGeASZg jj0/bJGhgUr9U7oG7Hh2F8vzpOqZrdd65MRkxmc7bWj1k81tOU2woR/Gy8xLzi0k0KUa8ueB iYOcZcIGTcs9CssVwQjYaXRoeT65LJnTxYZif2pfNxfINFzCGw42s3EtZFteczClKcVSJ1+L +QUY/J24x0/ocQX/M1PwtZbB4c/2Pg/t5FS+s6UB1Ce08xsJDcwyOPIH6O3tccZuriHgvqKP yKz/Ble76+NFlTK1mpUlfM7PVhD5XzrDUEHWRTeTJSvJ8TIPL4uyfzhjHhlkCU0mw7Pscyxn DE8G0UYMEaNgaZap8dcGMYH/96EfE5s/nTX0M6MXV0yots7U2BDb4soLCxLOJz4tAFDtNFtA wLBhXRSvWhdBJZiig/9CG3dXmKfi2H+wdUCSvEFHRpgo7GK8/Kh3vGhgKmnnxhl8ACBaGy9n fxjSxjSO6rj4/MeenmlJw1yebzkX8ZmaSi8BHe+n6jTGEFNrbiOdWpJgc5yHIZZnwXaW54QT UhhSjDL1rV2B4F28w30jYmlRmm2RdN7iCZfbyP3dvFQTzQ4ySquuPkIGcOOHrvZzxbRjzMx1 Mwqu3GQ= Message-ID: Date: Mon, 27 Apr 2020 10:09:31 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <178ab8fa.363e.170ebb22d94.Coremail.wangzk320@163.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [dpdk-dev] [ovs-dev] [PATCH] vhost: return -EAGAIN during unregistering vhost if it is busy. X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 3/18/20 4:31 AM, =E7=8E=8B=E5=BF=97=E5=85=8B wrote: > Involve openvswitch group since this fix is highly coupled with OVS. > welcome comment. > At 2020-03-12 17:57:19, "Zhike Wang" wrote: >> The vhost_user_read_cb() and rte_vhost_driver_unregister() >> can be called at the same time by 2 threads, and may lead to deadlock. >> Eg thread1 calls vhost_user_read_cb()->vhost_user_get_vring_base()->dest= roy_device(), >> then thread2 calls rte_vhost_driver_unregister(), and will retry the fds= et_try_del() in loop. >> >> Some application implements destroy_device() as a blocking function, eg >> OVS calls ovsrcu_synchronize() insides destroy_device(). As a result, >> thread1(eg vhost_events) is blocked to wait quiesce of thread2(eg ovs-vs= witchd), >> and thread2 is in a loop to wait thread1 to give up the use of the vhost= fd, >> then leads to deadlock. >> >> It is better to return -EAGAIN to application, who will decide how to ha= ndle >> (eg OVS can call ovsrcu_quiesce() and then retry). >> >> Signed-off-by: Zhike Wang >> --- >> lib/librte_vhost/rte_vhost.h | 4 +++- >> lib/librte_vhost/socket.c | 8 ++++---- >> 2 files changed, 7 insertions(+), 5 deletions(-) Isn't it fixed with below commit that landed into DPDK v20.02? commit 5efb18e85f7fdb436d3e56591656051c16802066 Author: Maxime Coquelin Date: Tue Jan 14 19:53:57 2020 +0100 vhost: fix deadlock on port deletion If the vhost-user application (e.g. OVS) deletes the vhost-user port while Qemu sends a vhost-user request, a deadlock can happen if the request handler tries to acquire vhost-user's global mutex, which is also locked by the vhost-user port deletion API (rte_vhost_driver_unregister). This patch prevents the deadlock by making rte_vhost_driver_unregister() to release the mutex and try again if a request is being handled to give a chance to the request handler to complete. Fixes: 8b4b949144b8 ("vhost: fix dead lock on closing in server mode") Fixes: 5fbb3941da9f ("vhost: introduce driver features related APIs") Cc: stable@dpdk.org Signed-off-by: Maxime Coquelin Reviewed-by: Tiwei Bie Acked-by: Eelco Chaudron >> diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h >> index c7b619a..276db11 100644 >> --- a/lib/librte_vhost/rte_vhost.h >> +++ b/lib/librte_vhost/rte_vhost.h >> @@ -389,7 +389,9 @@ void rte_vhost_log_used_vring(int vid, uint16_t vrin= g_idx, >> */ >> int rte_vhost_driver_register(const char *path, uint64_t flags); >> >> -/* Unregister vhost driver. This is only meaningful to vhost user. */ >> +/* Unregister vhost driver. This is only meaningful to vhost user. >> + * Return -EAGAIN if device is busy, and leave it to be handled by appl= ication. >> + */ >> int rte_vhost_driver_unregister(const char *path); >> >> /** >> diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c >> index 7c80121..a75a3f6 100644 >> --- a/lib/librte_vhost/socket.c >> +++ b/lib/librte_vhost/socket.c >> @@ -1027,7 +1027,8 @@ struct vhost_user_reconnect_list { >> } >> >> /** >> - * Unregister the specified vhost socket >> + * Unregister the specified vhost socket. >> + * Return -EAGAIN if device is busy, and leave it to be handled by appl= ication. >> */ >> int >> rte_vhost_driver_unregister(const char *path) >> @@ -1039,7 +1040,6 @@ struct vhost_user_reconnect_list { >> =09if (path =3D=3D NULL) >> =09=09return -1; >> >> -again: >> =09pthread_mutex_lock(&vhost_user.mutex); >> >> =09for (i =3D 0; i < vhost_user.vsocket_cnt; i++) { >> @@ -1063,7 +1063,7 @@ struct vhost_user_reconnect_list { >> =09=09=09=09=09pthread_mutex_unlock( >> =09=09=09=09=09=09=09&vsocket->conn_mutex); >> =09=09=09=09=09pthread_mutex_unlock(&vhost_user.mutex); >> -=09=09=09=09=09goto again; >> +=09=09=09=09=09return -EAGAIN; >> =09=09=09=09} >> >> =09=09=09=09VHOST_LOG_CONFIG(INFO, >> @@ -1085,7 +1085,7 @@ struct vhost_user_reconnect_list { >> =09=09=09=09if (fdset_try_del(&vhost_user.fdset, >> =09=09=09=09=09=09vsocket->socket_fd) =3D=3D -1) { >> =09=09=09=09=09pthread_mutex_unlock(&vhost_user.mutex); >> -=09=09=09=09=09goto again; >> +=09=09=09=09=09return -EAGAIN; >> =09=09=09=09} >> >> =09=09=09=09close(vsocket->socket_fd); >> --=20 >> 1.8.3.1 >> > _______________________________________________ > dev mailing list > dev@openvswitch.org > https://mail.openvswitch.org/mailman/listinfo/ovs-dev >=20