From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [0/7] EDAC, mce_amd: Issue decoded MCE through the tracepoint From: mark gross Message-Id: <20170903233704.GC90926@mtgdev> Date: Sun, 3 Sep 2017 16:37:04 -0700 To: Steven Rostedt Cc: Borislav Petkov , Tony Luck , linux-edac , Yazen Ghannam , X86 ML , LKML , Mauro Carvalho Chehab List-ID: T24gV2VkLCBBdWcgMzAsIDIwMTcgYXQgMDc6MzA6NThQTSAtMDQwMCwgU3RldmVuIFJvc3RlZHQg d3JvdGU6Cj4gT24gV2VkLCAzMCBBdWcgMjAxNyAxNDo0NzoxOSAtMDcwMAo+IG1hcmsgZ3Jvc3Mg PG1ncm9zc0BsaW51eC5pbnRlbC5jb20+IHdyb3RlOgo+IAo+IAo+ID4gPiAgc3RydWN0IGRlbnRy eSAqcmFzX2RlYnVnZnNfZGlyOwo+ID4gPiAgCj4gPiA+ICBzdGF0aWMgYXRvbWljX3QgdHJhY2Vf Y291bnQgPSBBVE9NSUNfSU5JVCgwKTsKPiA+ID4gQEAgLTEyLDcgKzE0LDkgQEAgRVhQT1JUX1NZ TUJPTF9HUEwocmFzX3VzZXJzcGFjZV9jb25zdW1lcnMpOwo+ID4gPiAgCj4gPiA+ICBzdGF0aWMg aW50IHRyYWNlX3Nob3coc3RydWN0IHNlcV9maWxlICptLCB2b2lkICp2KQo+ID4gPiAgewo+ID4g PiAtCXJldHVybiBhdG9taWNfcmVhZCgmdHJhY2VfY291bnQpOwo+ID4gPiArCXNlcV9wcmludGYo bSwgInJlYWRlcnM6JWRcbiIsIGF0b21pY19yZWFkKCZ0cmFjZV9jb3VudCkpOwo+ID4gPiArCXNl cV9wcmludGYobSwgImhhcyBkZWNvZGVyOiVkXG4iLCBtY2FfY2ZnLmhhc19kZWNvZGVyKTsgIAo+ ID4gCj4gPiBkbyB5b3Ugd2FudCB0byB3b3JyeSBhYm91dCB0aGlzIGRlYnVnZnMgaW50ZXJmYWNl cyBhcyBBQkk/Cj4gCj4gSXQncyB0aGUgb2xkLCBpZiBhIHRyZWUgZmFsbHMgaW4gdGhlIGZvcmVz dCBpc3N1ZS4gSWYgeW91IGJyZWFrIHRoZSBBQkkKPiBidXQgbm9ib2R5IGlzIGFyb3VuZCB0byBu b3RpY2UsIGRpZCBpdCByZWFsbHkgYnJlYWs/CgpwZXJoYXBzLCBidXQgd2hhdCBJIHdhcyB0cnlp bmcgdG8gcG9pbnQgb3V0IHdhczogIm11bHRpIGxpbmUgZGVidWdGUyBwcmludGYncwpsaWtlIHRo aXMgYXJlIHZlcnkgZWFzeSB0byBjaGFuZ2UgdG8gYXBwZW5kIG90aGVyIGluZm9ybWF0aW9uIGFu ZCB5b3UgbWlnaHQKd2FudCB0byB3b3JyeSBhYm91dCB0aGUgQUJJIGltcGxpY2F0aW9ucyB0aGF0 IGNvdWxkIGhhcHBlbiBpbiB0aGUgZnV0dXJlLiIKCi0tbWFyawo+IAo+ID4gZGVidWdmcyBjaGFu Z2VzIGhhdmUgYml0dGVuIG1lIG9uIG9uZSBzcGVjaWZpYyBPUyBpbiBpcnJpdGF0aW5nIHdheXMu Cj4gPiAKPiA+IEknbSBub3Qgc3VyZSB3aGF0IHRoZSB3b3JkIGlzIGZvciBkZWJ1Z2ZzIGludGVy ZmFjZXMgYXMgQUJJIHRoZXNlIGRheXMgc28gdGhpcwo+ID4gZmVlZGJhY2sgbWF5IGJlIG5vdCBz byB1c2VmdWwuCj4gCj4gSSBkaXNjdXNzZWQgdGhpcyB3aXRoIEJvcmlzIGJlZm9yZSBoZSBzZW50 IGl0IG91dC4gVGhlIGN1cnJlbnQgY29kZSBpcwo+IGFjdHVhbGx5IGJyb2tlbi4gVGhlIHRyYWNl X3Nob3coKSBsb29rcyB0byBiZSBqdXN0IGEgc3R1YiBmb3IgYSBoYWNrIHRvCj4gaGF2ZSB1c2Vy c3BhY2UgdGVsbCB0aGUga2VybmVsIGl0J3MgcmVhZGluZyBzb21ldGhpbmcgKHRoZQo+IHRyYWNl X2NvdW50KS4gVGhlIHRyYWNlX3Nob3coKSBmdW5jdGlvbiBoZXJlIHJldHVybnMgdGhlIHRyYWNl X2NvdW50LAo+IHdoaWNoIGlzIGp1c3Qgd3JvbmcuIFRoZSBzZXFfZmlsZSBzaG93IGZ1bmN0aW9u IGlzIHN1cHBvc2UgdG8gcmV0dXJuCj4gbGVzcyB0aGFuIHplcm8gb24gZXJyb3IsIHplcm8gb24g c3VjY2Vzcywgb3IgZ3JlYXRlciB0aGFuIHplcm8gaWYgdGhlCj4gc2hvdyBpcyBzdXBwb3NlIHRv IHNraXAgdGhlIGN1cnJlbnQgZmllbGQgYnV0IG5vdCBlcnJvciBvdXQuIFRoaXMKPiB0cmFjZV9z aG93KCkgZnVuY3Rpb24gZG9lc24ndCBhY3R1YWxseSBzaG93IGFueXRoaW5nLiBJZiB5b3UgY2F0 IHRoZQo+IGZpbGUsIGl0IHdpbGwgYmUgYmxhbmsuIFJldHVybmluZyB6ZXJvIG9yIGdyZWF0ZXIg dGhhbiB6ZXJvIGhhcyB0aGUKPiBzYW1lIGVmZmVjdC4gV2hpY2ggaXMgbm90aGluZy4KPiAKPiAt LSBTdGV2ZQo+IC0tCj4gVG8gdW5zdWJzY3JpYmUgZnJvbSB0aGlzIGxpc3Q6IHNlbmQgdGhlIGxp bmUgInVuc3Vic2NyaWJlIGxpbnV4LWVkYWMiIGluCj4gdGhlIGJvZHkgb2YgYSBtZXNzYWdlIHRv IG1ham9yZG9tb0B2Z2VyLmtlcm5lbC5vcmcKPiBNb3JlIG1ham9yZG9tbyBpbmZvIGF0ICBodHRw Oi8vdmdlci5rZXJuZWwub3JnL21ham9yZG9tby1pbmZvLmh0bWwKLS0tClRvIHVuc3Vic2NyaWJl IGZyb20gdGhpcyBsaXN0OiBzZW5kIHRoZSBsaW5lICJ1bnN1YnNjcmliZSBsaW51eC1lZGFjIiBp bgp0aGUgYm9keSBvZiBhIG1lc3NhZ2UgdG8gbWFqb3Jkb21vQHZnZXIua2VybmVsLm9yZwpNb3Jl IG1ham9yZG9tbyBpbmZvIGF0ICBodHRwOi8vdmdlci5rZXJuZWwub3JnL21ham9yZG9tby1pbmZv Lmh0bWwK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753098AbdICXhG (ORCPT ); Sun, 3 Sep 2017 19:37:06 -0400 Received: from mga03.intel.com ([134.134.136.65]:14982 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753005AbdICXhF (ORCPT ); Sun, 3 Sep 2017 19:37:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,472,1498546800"; d="scan'208";a="1010598055" Date: Sun, 3 Sep 2017 16:37:04 -0700 From: mark gross To: Steven Rostedt Cc: Borislav Petkov , Tony Luck , linux-edac , Yazen Ghannam , X86 ML , LKML , Mauro Carvalho Chehab Subject: Re: [PATCH 0/7] EDAC, mce_amd: Issue decoded MCE through the tracepoint Message-ID: <20170903233704.GC90926@mtgdev> Reply-To: mgross@linux.intel.com References: <20170825102411.8682-1-bp@alien8.de> <20170828134549.wh6toneoca47ff2w@pd.tnic> <20170830114843.deetnlz2wjbgbaj4@pd.tnic> <20170830214719.GC103314@mtgdev> <20170830193058.00740c87@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170830193058.00740c87@gandalf.local.home> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 30, 2017 at 07:30:58PM -0400, Steven Rostedt wrote: > On Wed, 30 Aug 2017 14:47:19 -0700 > mark gross wrote: > > > > > struct dentry *ras_debugfs_dir; > > > > > > static atomic_t trace_count = ATOMIC_INIT(0); > > > @@ -12,7 +14,9 @@ EXPORT_SYMBOL_GPL(ras_userspace_consumers); > > > > > > static int trace_show(struct seq_file *m, void *v) > > > { > > > - return atomic_read(&trace_count); > > > + seq_printf(m, "readers:%d\n", atomic_read(&trace_count)); > > > + seq_printf(m, "has decoder:%d\n", mca_cfg.has_decoder); > > > > do you want to worry about this debugfs interfaces as ABI? > > It's the old, if a tree falls in the forest issue. If you break the ABI > but nobody is around to notice, did it really break? perhaps, but what I was trying to point out was: "multi line debugFS printf's like this are very easy to change to append other information and you might want to worry about the ABI implications that could happen in the future." --mark > > > debugfs changes have bitten me on one specific OS in irritating ways. > > > > I'm not sure what the word is for debugfs interfaces as ABI these days so this > > feedback may be not so useful. > > I discussed this with Boris before he sent it out. The current code is > actually broken. The trace_show() looks to be just a stub for a hack to > have userspace tell the kernel it's reading something (the > trace_count). The trace_show() function here returns the trace_count, > which is just wrong. The seq_file show function is suppose to return > less than zero on error, zero on success, or greater than zero if the > show is suppose to skip the current field but not error out. This > trace_show() function doesn't actually show anything. If you cat the > file, it will be blank. Returning zero or greater than zero has the > same effect. Which is nothing. > > -- Steve > -- > To unsubscribe from this list: send the line "unsubscribe linux-edac" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html