From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [uml-devel] [REVIEW][PATCH 19/22] signal/um: Use force_sig_fault in relay_signal. Date: Tue, 24 Apr 2018 10:59:46 -0500 Message-ID: <87zi1sd28d.fsf@xmission.com> References: <87604mhrnb.fsf@xmission.com> <20180420143811.9994-19-ebiederm@xmission.com> <7074fe36-27c5-ee82-9659-da703cfc91fe@kot-begemot.co.uk> <7ddd238f-88a8-ed03-fe9e-0f4e5f2a490d@kot-begemot.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <7ddd238f-88a8-ed03-fe9e-0f4e5f2a490d@kot-begemot.co.uk> (Anton Ivanov's message of "Tue, 24 Apr 2018 09:44:22 +0100") Sender: linux-kernel-owner@vger.kernel.org To: Anton Ivanov Cc: Richard Weinberger , Linux-Arch , Richard Weinberger , Jeff Dike , linux-um@lists.infradead.org, LKML , "user-mode-linux-devel@lists.sourceforge.net" , Martin =?utf-8?Q?P=C3=A4rt?= =?utf-8?Q?el?= List-Id: linux-arch.vger.kernel.org Sigh I should have Cc'd Martin Partel as well as this bit is his original code. Anton Ivanov writes: > Hi Richard, > > There was a post to uml-devel during the days when the sourceforge mailing list > was working in random drop mode which claimed that "this fixes the arm build". > > I have not kept it locally and I do not see it the archive (I do not see a few > other posts there either - including some of mine). > > The joys of having a broken list :( > > Whoever posted it, if you are reading it, please re-post again so we can have a > look. > > In the meantime we are as you said - x86 only. The only case I can see my changed relay_signal affecting on arm is the nasty hach where errno is set in conjunction with trap_trace. Having a second look I really don't understand what relay_signal is trying to do. The function relay_signal does not pass siginfo through unchanged. The function relay_signal does not handle cases where si_code is not SI_USER or SI_KERNEL, or any of the other signal independent si_codes. In my change I believe I have preserved the character of relay_signal of just passing through the fault. Still even after reading the commit that upgraded relay_signal to preserve si_code and si_addr I really don't understand the intended logic. Am I missing something subtle or have the subtle details of siginfo just always been ignored? commit d3c1cfcdb43e023ab1b1c7a555cd9e929026500a Author: Martin Pärtel Date: Thu Aug 2 00:49:17 2012 +0200 um: pass siginfo to guest process UML guest processes now get correct siginfo_t for SIGTRAP, SIGFPE, SIGILL and SIGBUS. Specifically, si_addr and si_code are now correct where previously they were si_addr = NULL and si_code = 128. Signed-off-by: Martin Pärtel Signed-off-by: Richard Weinberger Eric From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: ebiederm@xmission.com (Eric W. Biederman) References: <87604mhrnb.fsf@xmission.com> <20180420143811.9994-19-ebiederm@xmission.com> <7074fe36-27c5-ee82-9659-da703cfc91fe@kot-begemot.co.uk> <7ddd238f-88a8-ed03-fe9e-0f4e5f2a490d@kot-begemot.co.uk> Date: Tue, 24 Apr 2018 10:59:46 -0500 In-Reply-To: <7ddd238f-88a8-ed03-fe9e-0f4e5f2a490d@kot-begemot.co.uk> (Anton Ivanov's message of "Tue, 24 Apr 2018 09:44:22 +0100") Message-ID: <87zi1sd28d.fsf@xmission.com> MIME-Version: 1.0 Subject: Re: [uml-devel] [REVIEW][PATCH 19/22] signal/um: Use force_sig_fault in relay_signal. List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: Anton Ivanov Cc: Linux-Arch , "user-mode-linux-devel@lists.sourceforge.net" , Richard Weinberger , Richard Weinberger , Jeff Dike , linux-um@lists.infradead.org, LKML , Martin =?utf-8?Q?P=C3=A4rt?= =?utf-8?Q?el?= List-ID: U2lnaCBJIHNob3VsZCBoYXZlIENjJ2QgTWFydGluIFBhcnRlbCBhcyB3ZWxsIGFzIHRoaXMgYml0 IGlzIGhpcwpvcmlnaW5hbCBjb2RlLgoKQW50b24gSXZhbm92IDxhbnRvbi5pdmFub3ZAa290LWJl Z2Vtb3QuY28udWs+IHdyaXRlczoKCj4gSGkgUmljaGFyZCwKPgo+IFRoZXJlIHdhcyBhIHBvc3Qg dG8gdW1sLWRldmVsIGR1cmluZyB0aGUgZGF5cyB3aGVuIHRoZSBzb3VyY2Vmb3JnZSBtYWlsaW5n IGxpc3QKPiB3YXMgd29ya2luZyBpbiByYW5kb20gZHJvcCBtb2RlIHdoaWNoIGNsYWltZWQgdGhh dCAidGhpcyBmaXhlcyB0aGUgYXJtIGJ1aWxkIi4KPgo+IEkgaGF2ZSBub3Qga2VwdCBpdCBsb2Nh bGx5IGFuZCBJIGRvIG5vdCBzZWUgaXQgdGhlIGFyY2hpdmUgKEkgZG8gbm90IHNlZSBhIGZldwo+ IG90aGVyIHBvc3RzIHRoZXJlIGVpdGhlciAtIGluY2x1ZGluZyBzb21lIG9mIG1pbmUpLgo+Cj4g VGhlIGpveXMgb2YgaGF2aW5nIGEgYnJva2VuIGxpc3QgOigKPgo+IFdob2V2ZXIgcG9zdGVkIGl0 LCBpZiB5b3UgYXJlIHJlYWRpbmcgaXQsIHBsZWFzZSByZS1wb3N0IGFnYWluIHNvIHdlIGNhbiBo YXZlIGEKPiBsb29rLgo+Cj4gSW4gdGhlIG1lYW50aW1lIHdlIGFyZSBhcyB5b3Ugc2FpZCAtIHg4 NiBvbmx5LgoKVGhlIG9ubHkgY2FzZSBJIGNhbiBzZWUgbXkgY2hhbmdlZCByZWxheV9zaWduYWwg YWZmZWN0aW5nIG9uIGFybSBpcyB0aGUKbmFzdHkgaGFjaCB3aGVyZSBlcnJubyBpcyBzZXQgaW4g Y29uanVuY3Rpb24gd2l0aCB0cmFwX3RyYWNlLgoKSGF2aW5nIGEgc2Vjb25kIGxvb2sgSSByZWFs bHkgZG9uJ3QgdW5kZXJzdGFuZCB3aGF0IHJlbGF5X3NpZ25hbCBpcwp0cnlpbmcgdG8gZG8uCgpU aGUgZnVuY3Rpb24gcmVsYXlfc2lnbmFsIGRvZXMgbm90IHBhc3Mgc2lnaW5mbyB0aHJvdWdoIHVu Y2hhbmdlZC4KVGhlIGZ1bmN0aW9uIHJlbGF5X3NpZ25hbCBkb2VzIG5vdCBoYW5kbGUgY2FzZXMg d2hlcmUgc2lfY29kZSBpcwpub3QgU0lfVVNFUiBvciBTSV9LRVJORUwsIG9yIGFueSBvZiB0aGUg b3RoZXIgc2lnbmFsIGluZGVwZW5kZW50CnNpX2NvZGVzLgoKSW4gbXkgY2hhbmdlIEkgYmVsaWV2 ZSBJIGhhdmUgcHJlc2VydmVkIHRoZSBjaGFyYWN0ZXIgb2YgcmVsYXlfc2lnbmFsIG9mCmp1c3Qg cGFzc2luZyB0aHJvdWdoIHRoZSBmYXVsdC4KClN0aWxsIGV2ZW4gYWZ0ZXIgcmVhZGluZyB0aGUg Y29tbWl0IHRoYXQgdXBncmFkZWQgcmVsYXlfc2lnbmFsIHRvCnByZXNlcnZlIHNpX2NvZGUgYW5k IHNpX2FkZHIgSSByZWFsbHkgZG9uJ3QgdW5kZXJzdGFuZCB0aGUgaW50ZW5kZWQKbG9naWMuCgpB bSBJIG1pc3Npbmcgc29tZXRoaW5nIHN1YnRsZSBvciBoYXZlIHRoZSBzdWJ0bGUgZGV0YWlscyBv ZiBzaWdpbmZvIGp1c3QKYWx3YXlzIGJlZW4gaWdub3JlZD8KCmNvbW1pdCBkM2MxY2ZjZGI0M2Uw MjNhYjFiMWM3YTU1NWNkOWU5MjkwMjY1MDBhCkF1dGhvcjogTWFydGluIFDDpHJ0ZWwgPG1hcnRp bi5wYXJ0ZWxAZ21haWwuY29tPgpEYXRlOiAgIFRodSBBdWcgMiAwMDo0OToxNyAyMDEyICswMjAw CgogICAgdW06IHBhc3Mgc2lnaW5mbyB0byBndWVzdCBwcm9jZXNzCiAgICAKICAgIFVNTCBndWVz dCBwcm9jZXNzZXMgbm93IGdldCBjb3JyZWN0IHNpZ2luZm9fdCBmb3IgU0lHVFJBUCwgU0lHRlBF LAogICAgU0lHSUxMIGFuZCBTSUdCVVMuIFNwZWNpZmljYWxseSwgc2lfYWRkciBhbmQgc2lfY29k ZSBhcmUgbm93IGNvcnJlY3QKICAgIHdoZXJlIHByZXZpb3VzbHkgdGhleSB3ZXJlIHNpX2FkZHIg PSBOVUxMIGFuZCBzaV9jb2RlID0gMTI4LgogICAgCiAgICBTaWduZWQtb2ZmLWJ5OiBNYXJ0aW4g UMOkcnRlbCA8bWFydGluLnBhcnRlbEBnbWFpbC5jb20+CiAgICBTaWduZWQtb2ZmLWJ5OiBSaWNo YXJkIFdlaW5iZXJnZXIgPHJpY2hhcmRAbm9kLmF0PgoKRXJpYwoKCi0tLS0tLS0tLS0tLS0tLS0t LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0t LS0tLQpDaGVjayBvdXQgdGhlIHZpYnJhbnQgdGVjaCBjb21tdW5pdHkgb24gb25lIG9mIHRoZSB3 b3JsZCdzIG1vc3QKZW5nYWdpbmcgdGVjaCBzaXRlcywgU2xhc2hkb3Qub3JnISBodHRwOi8vc2Rt Lmxpbmsvc2xhc2hkb3QKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX18KVXNlci1tb2RlLWxpbnV4LWRldmVsIG1haWxpbmcgbGlzdApVc2VyLW1vZGUtbGludXgt ZGV2ZWxAbGlzdHMuc291cmNlZm9yZ2UubmV0Cmh0dHBzOi8vbGlzdHMuc291cmNlZm9yZ2UubmV0 L2xpc3RzL2xpc3RpbmZvL3VzZXItbW9kZS1saW51eC1kZXZlbAo=