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=-6.7 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 E42B0C432C0 for ; Thu, 28 Nov 2019 08:41:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1D8B2158A for ; Thu, 28 Nov 2019 08:41:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727460AbfK1IlT convert rfc822-to-8bit (ORCPT ); Thu, 28 Nov 2019 03:41:19 -0500 Received: from lithops.sigma-star.at ([195.201.40.130]:49034 "EHLO lithops.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726937AbfK1IlT (ORCPT ); Thu, 28 Nov 2019 03:41:19 -0500 Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id C0F90605A915; Thu, 28 Nov 2019 09:41:15 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id 6HwXfqQxNdPA; Thu, 28 Nov 2019 09:41:12 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 743CB607BD98; Thu, 28 Nov 2019 09:41:12 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id XTUUL9IeyYvs; Thu, 28 Nov 2019 09:41:12 +0100 (CET) Received: from lithops.sigma-star.at (lithops.sigma-star.at [195.201.40.130]) by lithops.sigma-star.at (Postfix) with ESMTP id 3F62F605A915; Thu, 28 Nov 2019 09:41:12 +0100 (CET) Date: Thu, 28 Nov 2019 09:41:12 +0100 (CET) From: Richard Weinberger To: anton ivanov Cc: Dan Carpenter , Wei Yongjun , Song Liu , Daniel Borkmann , kernel-janitors , Jeff Dike , linux-um , Alexei Starovoitov , netdev , bpf@vger.kernel.org, Martin KaFai Lau Message-ID: <1784077834.99875.1574930472125.JavaMail.zimbra@nod.at> In-Reply-To: <5892ee7c-ff24-fb3c-6911-44e0b1d5895f@cambridgegreys.com> References: <20191128020147.191893-1-weiyongjun1@huawei.com> <20191128080641.GD1781@kadam> <5892ee7c-ff24-fb3c-6911-44e0b1d5895f@cambridgegreys.com> Subject: Re: [PATCH -next] um: vector: use GFP_ATOMIC under spin lock MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Originating-IP: [195.201.40.130] X-Mailer: Zimbra 8.8.12_GA_3807 (ZimbraWebClient - FF68 (Linux)/8.8.12_GA_3809) Thread-Topic: vector: use GFP_ATOMIC under spin lock Thread-Index: 2J60FgWBh1I2FSErd4xdDGw7I9dybg== Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org ----- Ursprüngliche Mail ----- > Von: "anton ivanov" > An: "Dan Carpenter" , "Wei Yongjun" > CC: "Song Liu" , "Daniel Borkmann" , "kernel-janitors" > , "richard" , "Jeff Dike" , "linux-um" > , "Alexei Starovoitov" , "netdev" , > bpf@vger.kernel.org, "Martin KaFai Lau" > Gesendet: Donnerstag, 28. November 2019 09:18:30 > Betreff: Re: [PATCH -next] um: vector: use GFP_ATOMIC under spin lock > On 28/11/2019 08:06, Dan Carpenter wrote: >> On Thu, Nov 28, 2019 at 02:01:47AM +0000, Wei Yongjun wrote: >>> A spin lock is taken here so we should use GFP_ATOMIC. >>> >>> Fixes: 9807019a62dc ("um: Loadable BPF "Firmware" for vector drivers") >>> Signed-off-by: Wei Yongjun >>> --- >>> arch/um/drivers/vector_kern.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c >>> index 92617e16829e..6ff0065a271d 100644 >>> --- a/arch/um/drivers/vector_kern.c >>> +++ b/arch/um/drivers/vector_kern.c >>> @@ -1402,7 +1402,7 @@ static int vector_net_load_bpf_flash(struct net_device >>> *dev, >>> kfree(vp->bpf->filter); >>> vp->bpf->filter = NULL; >>> } else { >>> - vp->bpf = kmalloc(sizeof(struct sock_fprog), GFP_KERNEL); >>> + vp->bpf = kmalloc(sizeof(struct sock_fprog), GFP_ATOMIC); >>> if (vp->bpf == NULL) { >>> netdev_err(dev, "failed to allocate memory for firmware\n"); >>> goto flash_fail; >>> @@ -1414,7 +1414,7 @@ static int vector_net_load_bpf_flash(struct net_device >>> *dev, >>> if (request_firmware(&fw, efl->data, &vdevice->pdev.dev)) >> ^^^^^^^^^^^^^^^^ >> >> Is it really possible to call request_firmware() while holding a >> spin_lock? I was so sure that read from the disk. > > Works, I tested the patch quite a few times. It works because of the nature of UML ->no SMP or PREEMPT. But better request the firmware before taking the spinlock. request_firmware() can block. Same for the kmalloc(), just allocate the buffer before and then assign the pointer under the lock. That way you don't need GFP_ATOMIC. Thanks, //richard From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Weinberger Date: Thu, 28 Nov 2019 08:41:12 +0000 Subject: Re: [PATCH -next] um: vector: use GFP_ATOMIC under spin lock Message-Id: <1784077834.99875.1574930472125.JavaMail.zimbra@nod.at> List-Id: References: <20191128020147.191893-1-weiyongjun1@huawei.com> <20191128080641.GD1781@kadam> <5892ee7c-ff24-fb3c-6911-44e0b1d5895f@cambridgegreys.com> In-Reply-To: <5892ee7c-ff24-fb3c-6911-44e0b1d5895f@cambridgegreys.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: anton ivanov Cc: Dan Carpenter , Wei Yongjun , Song Liu , Daniel Borkmann , kernel-janitors , Jeff Dike , linux-um , Alexei Starovoitov , netdev , bpf@vger.kernel.org, Martin KaFai Lau ----- Urspr=C3=BCngliche Mail ----- > Von: "anton ivanov" > An: "Dan Carpenter" , "Wei Yongjun" > CC: "Song Liu" , "Daniel Borkmann" , "kernel-janitors" > , "richard" , "Jeff Dike= " , "linux-um" > , "Alexei Starovoitov" , "n= etdev" , > bpf@vger.kernel.org, "Martin KaFai Lau" > Gesendet: Donnerstag, 28. November 2019 09:18:30 > Betreff: Re: [PATCH -next] um: vector: use GFP_ATOMIC under spin lock > On 28/11/2019 08:06, Dan Carpenter wrote: >> On Thu, Nov 28, 2019 at 02:01:47AM +0000, Wei Yongjun wrote: >>> A spin lock is taken here so we should use GFP_ATOMIC. >>> >>> Fixes: 9807019a62dc ("um: Loadable BPF "Firmware" for vector drivers") >>> Signed-off-by: Wei Yongjun >>> --- >>> arch/um/drivers/vector_kern.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_ker= n.c >>> index 92617e16829e..6ff0065a271d 100644 >>> --- a/arch/um/drivers/vector_kern.c >>> +++ b/arch/um/drivers/vector_kern.c >>> @@ -1402,7 +1402,7 @@ static int vector_net_load_bpf_flash(struct net_d= evice >>> *dev, >>> kfree(vp->bpf->filter); >>> vp->bpf->filter =3D NULL; >>> } else { >>> - vp->bpf =3D kmalloc(sizeof(struct sock_fprog), GFP_KERNEL); >>> + vp->bpf =3D kmalloc(sizeof(struct sock_fprog), GFP_ATOMIC); >>> if (vp->bpf =3D NULL) { >>> netdev_err(dev, "failed to allocate memory for firmware\n"); >>> goto flash_fail; >>> @@ -1414,7 +1414,7 @@ static int vector_net_load_bpf_flash(struct net_d= evice >>> *dev, >>> if (request_firmware(&fw, efl->data, &vdevice->pdev.dev)) >> ^^^^^^^^^^^^^^^^ >>=20 >> Is it really possible to call request_firmware() while holding a >> spin_lock? I was so sure that read from the disk. >=20 > Works, I tested the patch quite a few times. It works because of the nature of UML ->no SMP or PREEMPT. But better request the firmware before taking the spinlock. request_firmware() can block. Same for the kmalloc(), just allocate the buffer before and then assign the pointer under the lock. That way you don't need GFP_ATOMIC. Thanks, //richard From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lithops.sigma-star.at ([195.201.40.130]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iaFMV-0007lC-Gn for linux-um@lists.infradead.org; Thu, 28 Nov 2019 08:41:21 +0000 Date: Thu, 28 Nov 2019 09:41:12 +0100 (CET) From: Richard Weinberger Message-ID: <1784077834.99875.1574930472125.JavaMail.zimbra@nod.at> In-Reply-To: <5892ee7c-ff24-fb3c-6911-44e0b1d5895f@cambridgegreys.com> References: <20191128020147.191893-1-weiyongjun1@huawei.com> <20191128080641.GD1781@kadam> <5892ee7c-ff24-fb3c-6911-44e0b1d5895f@cambridgegreys.com> Subject: Re: [PATCH -next] um: vector: use GFP_ATOMIC under spin lock MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: anton ivanov Cc: Song Liu , Daniel Borkmann , linux-um , Jeff Dike , kernel-janitors , Alexei Starovoitov , Wei Yongjun , netdev , bpf@vger.kernel.org, Martin KaFai Lau , Dan Carpenter LS0tLS0gVXJzcHLDvG5nbGljaGUgTWFpbCAtLS0tLQo+IFZvbjogImFudG9uIGl2YW5vdiIgPGFu dG9uLml2YW5vdkBjYW1icmlkZ2VncmV5cy5jb20+Cj4gQW46ICJEYW4gQ2FycGVudGVyIiA8ZGFu LmNhcnBlbnRlckBvcmFjbGUuY29tPiwgIldlaSBZb25nanVuIiA8d2VpeW9uZ2p1bjFAaHVhd2Vp LmNvbT4KPiBDQzogIlNvbmcgTGl1IiA8c29uZ2xpdWJyYXZpbmdAZmIuY29tPiwgIkRhbmllbCBC b3JrbWFubiIgPGRhbmllbEBpb2dlYXJib3gubmV0PiwgImtlcm5lbC1qYW5pdG9ycyIKPiA8a2Vy bmVsLWphbml0b3JzQHZnZXIua2VybmVsLm9yZz4sICJyaWNoYXJkIiA8cmljaGFyZEBub2QuYXQ+ LCAiSmVmZiBEaWtlIiA8amRpa2VAYWRkdG9pdC5jb20+LCAibGludXgtdW0iCj4gPGxpbnV4LXVt QGxpc3RzLmluZnJhZGVhZC5vcmc+LCAiQWxleGVpIFN0YXJvdm9pdG92IiA8YXN0QGtlcm5lbC5v cmc+LCAibmV0ZGV2IiA8bmV0ZGV2QHZnZXIua2VybmVsLm9yZz4sCj4gYnBmQHZnZXIua2VybmVs Lm9yZywgIk1hcnRpbiBLYUZhaSBMYXUiIDxrYWZhaUBmYi5jb20+Cj4gR2VzZW5kZXQ6IERvbm5l cnN0YWcsIDI4LiBOb3ZlbWJlciAyMDE5IDA5OjE4OjMwCj4gQmV0cmVmZjogUmU6IFtQQVRDSCAt bmV4dF0gdW06IHZlY3RvcjogdXNlIEdGUF9BVE9NSUMgdW5kZXIgc3BpbiBsb2NrCgo+IE9uIDI4 LzExLzIwMTkgMDg6MDYsIERhbiBDYXJwZW50ZXIgd3JvdGU6Cj4+IE9uIFRodSwgTm92IDI4LCAy MDE5IGF0IDAyOjAxOjQ3QU0gKzAwMDAsIFdlaSBZb25nanVuIHdyb3RlOgo+Pj4gQSBzcGluIGxv Y2sgaXMgdGFrZW4gaGVyZSBzbyB3ZSBzaG91bGQgdXNlIEdGUF9BVE9NSUMuCj4+Pgo+Pj4gRml4 ZXM6IDk4MDcwMTlhNjJkYyAoInVtOiBMb2FkYWJsZSBCUEYgIkZpcm13YXJlIiBmb3IgdmVjdG9y IGRyaXZlcnMiKQo+Pj4gU2lnbmVkLW9mZi1ieTogV2VpIFlvbmdqdW4gPHdlaXlvbmdqdW4xQGh1 YXdlaS5jb20+Cj4+PiAtLS0KPj4+ICAgYXJjaC91bS9kcml2ZXJzL3ZlY3Rvcl9rZXJuLmMgfCA0 ICsrLS0KPj4+ICAgMSBmaWxlIGNoYW5nZWQsIDIgaW5zZXJ0aW9ucygrKSwgMiBkZWxldGlvbnMo LSkKPj4+Cj4+PiBkaWZmIC0tZ2l0IGEvYXJjaC91bS9kcml2ZXJzL3ZlY3Rvcl9rZXJuLmMgYi9h cmNoL3VtL2RyaXZlcnMvdmVjdG9yX2tlcm4uYwo+Pj4gaW5kZXggOTI2MTdlMTY4MjllLi42ZmYw MDY1YTI3MWQgMTAwNjQ0Cj4+PiAtLS0gYS9hcmNoL3VtL2RyaXZlcnMvdmVjdG9yX2tlcm4uYwo+ Pj4gKysrIGIvYXJjaC91bS9kcml2ZXJzL3ZlY3Rvcl9rZXJuLmMKPj4+IEBAIC0xNDAyLDcgKzE0 MDIsNyBAQCBzdGF0aWMgaW50IHZlY3Rvcl9uZXRfbG9hZF9icGZfZmxhc2goc3RydWN0IG5ldF9k ZXZpY2UKPj4+ICpkZXYsCj4+PiAgIAkJa2ZyZWUodnAtPmJwZi0+ZmlsdGVyKTsKPj4+ICAgCQl2 cC0+YnBmLT5maWx0ZXIgPSBOVUxMOwo+Pj4gICAJfSBlbHNlIHsKPj4+IC0JCXZwLT5icGYgPSBr bWFsbG9jKHNpemVvZihzdHJ1Y3Qgc29ja19mcHJvZyksIEdGUF9LRVJORUwpOwo+Pj4gKwkJdnAt PmJwZiA9IGttYWxsb2Moc2l6ZW9mKHN0cnVjdCBzb2NrX2Zwcm9nKSwgR0ZQX0FUT01JQyk7Cj4+ PiAgIAkJaWYgKHZwLT5icGYgPT0gTlVMTCkgewo+Pj4gICAJCQluZXRkZXZfZXJyKGRldiwgImZh aWxlZCB0byBhbGxvY2F0ZSBtZW1vcnkgZm9yIGZpcm13YXJlXG4iKTsKPj4+ICAgCQkJZ290byBm bGFzaF9mYWlsOwo+Pj4gQEAgLTE0MTQsNyArMTQxNCw3IEBAIHN0YXRpYyBpbnQgdmVjdG9yX25l dF9sb2FkX2JwZl9mbGFzaChzdHJ1Y3QgbmV0X2RldmljZQo+Pj4gKmRldiwKPj4+ICAgCWlmIChy ZXF1ZXN0X2Zpcm13YXJlKCZmdywgZWZsLT5kYXRhLCAmdmRldmljZS0+cGRldi5kZXYpKQo+PiAg ICAgICAgICAgICAgXl5eXl5eXl5eXl5eXl5eXgo+PiAKPj4gSXMgaXQgcmVhbGx5IHBvc3NpYmxl IHRvIGNhbGwgcmVxdWVzdF9maXJtd2FyZSgpIHdoaWxlIGhvbGRpbmcgYQo+PiBzcGluX2xvY2s/ ICBJIHdhcyBzbyBzdXJlIHRoYXQgcmVhZCBmcm9tIHRoZSBkaXNrLgo+IAo+IFdvcmtzLCBJIHRl c3RlZCB0aGUgcGF0Y2ggcXVpdGUgYSBmZXcgdGltZXMuCgpJdCB3b3JrcyBiZWNhdXNlIG9mIHRo ZSBuYXR1cmUgb2YgVU1MIC0+bm8gIFNNUCBvciBQUkVFTVBULgpCdXQgYmV0dGVyIHJlcXVlc3Qg dGhlIGZpcm13YXJlIGJlZm9yZSB0YWtpbmcgdGhlIHNwaW5sb2NrLgpyZXF1ZXN0X2Zpcm13YXJl KCkgY2FuIGJsb2NrLgpTYW1lIGZvciB0aGUga21hbGxvYygpLCBqdXN0IGFsbG9jYXRlIHRoZSBi dWZmZXIgYmVmb3JlIGFuZCB0aGVuIGFzc2lnbgp0aGUgcG9pbnRlciB1bmRlciB0aGUgbG9jay4g VGhhdCB3YXkgeW91IGRvbid0IG5lZWQgR0ZQX0FUT01JQy4KClRoYW5rcywKLy9yaWNoYXJkCgpf X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpsaW51eC11bSBt YWlsaW5nIGxpc3QKbGludXgtdW1AbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5m cmFkZWFkLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4LXVtCg==