From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.skyhub.de ([2a01:4f8:120:8448::d00d]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1a4QJB-0001Yt-TY for kexec@lists.infradead.org; Thu, 03 Dec 2015 09:36:15 +0000 Date: Thu, 3 Dec 2015 10:35:44 +0100 From: Borislav Petkov Subject: Re: [V5 PATCH 3/4] kexec: Fix race between panic() and crash_kexec() called directly Message-ID: <20151203093544.GC22271@pd.tnic> References: <20151120093641.4285.97253.stgit@softrs> <20151120093648.4285.17715.stgit@softrs> <20151125095457.GB29499@pd.tnic> <04EAB7311EE43145B2D3536183D1A84454A3B032@GSjpTKYDCembx31.service.hitachi.net> <20151202154023.GH3783@pd.tnic> <04EAB7311EE43145B2D3536183D1A84454A3CD95@GSjpTKYDCembx31.service.hitachi.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <04EAB7311EE43145B2D3536183D1A84454A3CD95@GSjpTKYDCembx31.service.hitachi.net> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: =?utf-8?B?5rKz5ZCI6Iux5a6PIC8gS0FXQUnvvIxISURFSElSTw==?= Cc: "x86@kernel.org" , Baoquan He , Jonathan Corbet , Peter Zijlstra , "linux-doc@vger.kernel.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Michal Hocko , Thomas Gleixner , "Eric W. Biederman" , "H. Peter Anvin" , =?utf-8?B?5bmz5p2+6ZuF5bezIC8gSElSQU1BVFXvvIxNQVNBTUk=?= , Andrew Morton , Ingo Molnar , Vivek Goyal T24gVGh1LCBEZWMgMDMsIDIwMTUgYXQgMDI6MDE6MzhBTSArMDAwMCwg5rKz5ZCI6Iux5a6PIC8g S0FXQUnvvIxISURFSElSTyB3cm90ZToKPiA+IE9uIFdlZCwgRGVjIDAyLCAyMDE1IGF0IDExOjU3 OjM4QU0gKzAwMDAsIOays+WQiOiLseWujyAvIEtBV0FJ77yMSElERUhJUk8gd3JvdGU6Cj4gPiA+ IFdlIGNhbiBkbyBzbywgYnV0IEkgdGhpbmsgcmVzZXR0aW5nIHBhbmljX2NwdSBhbHdheXMgd291 bGQgYmUKPiA+ID4gc2ltcGxlciBhbmQgc2FmZXIuCj4gCj4gSSdsbCBzdGF0ZSBpbiBkZXRhaWwu Cj4gCj4gV2hlbiB3ZSBjYWxsIGNyYXNoX2tleGVjKCkgd2l0aG91dCBlbnRlcmluZyBwYW5pYygp IGFuZCByZXR1cm4gZnJvbQo+IGl0LCBwYW5pYygpIHNob3VsZCBiZSBjYWxsZWQgZXZlbnR1YWxs eS4KCkh1aCwgdGhlIGNhbGwgY2hhaW4gaXMKCnBhbmljLT5jcmFzaF9rZXhlYwoKT3IgZG8geW91 IG1lYW4sIHdoZW4gY3Jhc2hfa2V4ZWMoKSBpcyBub3QgY2FsbGVkIGJ5IHBhbmljKCkgYnV0IGJ5 IHNvbWUKb2YgaXRzIG90aGVyIGNhbGxlcnM/Cgo+IEJ1dCB0aGUgY29kZSBwYXRocyBhcmUgYSBi aXQgY29tcGxpY2F0ZWQgYW5kIHRoZXJlIGFyZSBtYW55Cj4gaW1wbGVtZW50YXRpb25zIGZvciBl YWNoIGFyY2hpdGVjdHVyZS4gU28gb25lIGRheSwgdGhpcyBhc3N1bXB0aW9uIG1heQo+IGJlIGJy b2tlbjsgdGhlIENQVSBkb2Vzbid0IGNhbGwgcGFuaWMoKS4gT3IgdGhlIENQVSBtYXkgZmFpbCB0 byBjYWxsCj4gcGFuaWMoKSBiZWNhdXNlIHdlIGFyZSBhbHJlYWR5IGluIGluc2FuZSBzdGF0ZS4g SXQgd291bGQgYmUgbmVydm91cywKPiBidXQgYWxsb3dpbmcgYW5vdGhlciBDUFUgdG8gcHJvY2Vz cyBwYW5pYyByb3V0aW5lcyBieSByZXNldHRpbmcKPiBwYW5pY19jcHUgaXMgc2FmZXIgYXBwcm9h Y2guCgpNeSBzdWdnZXN0aW9uIHdhcyB0byBkbyB0aGlzIG9ubHkgb24gdGhlIHBhbmljIHBhdGgg LSBub3QgbmVjZXNzYXJpbHkgb24KdGhlIG90aGVycy4KCj4gU2luY2UgdGhpcyBjb2RlIGlzIGV4 ZWN1dGVkIG9ubHkgb25jZSBkdWUgdG8gcGFuaWNfY3B1LAo+IEkgdGhpbmsgaW50cm9kdWNpbmcg dGhpcyBsb2dpYyBpcyBub3QgbXVjaCB2YWx1YWJsZS4KPiBBbHNvLCBjdXJyZW50IGltcGxlbWVu dGF0aW9uIGlzIGFscmVhZHkgcXVpdGUgc2ltcGxlOgo+IAo+IHBhbmljKCkKPiB7Cj4gLi4uCj4g CV9fY3Jhc2hfa2V4ZWMoTlVMTCkgewo+IAkJaWYgKG11dGV4X3RyeWxvY2soJmtleGVjX211dGV4 KSkgewo+IAkJCWlmIChrZXhlY19jcmFzaF9pbWFnZSkgewo+IAkJCQkvKiBkb24ndCByZXR1cm4g Ki8KPiAJCQl9CgpJIGRvbid0IG1lYW4gdGhlIGtleGVjX2NyYXNoX2ltYWdlIGNhc2UgLSBJIG1l YW4gdGhlIG9wcG9zaXRlIG9uZToKIWtleGVjX2NyYXNoX2ltYWdlLiBBbmQgSSB0aGluayBJIGtu b3cgbm93IHdoYXQgeW91J3JlIHRyeWluZyB0byB0ZWxsCm1lOiB0aGUgZmlyc3QgQ1BVIHdoaWNo IGhpdHMgcGFuaWMsIHdpbGwgZmluaXNoIHBhbmljIGV2ZW50dWFsbHkgYW5kIHNvCml0IHdpbGwg dGFrZSBkb3duIHRoZSBtYWNoaW5lLgoKRXZlcnkgb3RoZXIgQ1BVIHdoaWNoIGhhcHBlbnMgdG8g ZW50ZXIgcGFuaWMgaW4gYmV0d2VlbiB0aGUgZmlyc3QgQ1BVCmFuZCB0aGUgbWFjaGluZSBiZWlu ZyB0YWtlbiBkb3duLCBkb2Vzbid0IG1hdHRlciBiZWNhdXNlLCB3ZWxsLCB3aG8KY2FyZXMsIHdl J3JlIHBhbmlja2luZyBhbHJlYWR5LgoKQW0gSSBjbG9zZT8KCi0tIApSZWdhcmRzL0dydXNzLAog ICAgQm9yaXMuCgpFQ08gdGlwICMxMDE6IFRyaW0geW91ciBtYWlscyB3aGVuIHlvdSByZXBseS4K Cl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmtleGVjIG1h aWxpbmcgbGlzdAprZXhlY0BsaXN0cy5pbmZyYWRlYWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRl YWQub3JnL21haWxtYW4vbGlzdGluZm8va2V4ZWMK