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(p200300cbc7309700d653fb1975e5ab5c.dip0.t-ipconnect.de. [2003:cb:c730:9700:d653:fb19:75e5:ab5c]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-37d7fa92741sm1240283f8f.60.2024.10.15.03.41.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 15 Oct 2024 03:41:01 -0700 (PDT) Message-ID: Date: Tue, 15 Oct 2024 12:40:59 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/7] s390/kdump: implement is_kdump_kernel() To: Heiko Carstens Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, linux-doc@vger.kernel.org, kvm@vger.kernel.org, Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?Q?Eugenio_P=C3=A9rez?= , Andrew Morton , Jonathan Corbet , Mario Casquero , Alexander Egorenkov , Mikhail Zaslonko References: <20241014144622.876731-1-david@redhat.com> <20241014144622.876731-2-david@redhat.com> <20241014182054.10447-D-hca@linux.ibm.com> <20241015083040.7641-C-hca@linux.ibm.com> <0c7e876f-5648-4a82-b809-ca48f778b4a6@redhat.com> <20241015100854.7641-J-hca@linux.ibm.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20241015100854.7641-J-hca@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 15.10.24 12:08, Heiko Carstens wrote: > On Tue, Oct 15, 2024 at 10:41:21AM +0200, David Hildenbrand wrote: >> On 15.10.24 10:30, Heiko Carstens wrote: >>> On Mon, Oct 14, 2024 at 09:26:03PM +0200, David Hildenbrand wrote: >>>> On 14.10.24 20:20, Heiko Carstens wrote: >>>>> Looks like this could work. But the comment in smp.c above >>>>> dump_available() needs to be updated. >>>> >>>> A right, I remember that there was some outdated documentation. > > ... > >> My concern is that we'll now have >> >> bool is_kdump_kernel(void) >> { >> return oldmem_data.start && !is_ipl_type_dump(); >> } >> >> Which matches 3), but if 2) is also called "kdump", then should it actually >> be >> >> bool is_kdump_kernel(void) >> { >> return oldmem_data.start; >> } >> >> ? >> >> When I wrote that code I was rather convinced that the variant in this patch >> is the right thing to do. > > Oh well, we simply of too many dump options. I'll let Alexander and > Mikhail better comment on this :) Thanks! > > Alexander, Mikhail, the discussion starts here, and we need a sane > is_kdump_kernel() for s390: > https://lore.kernel.org/all/20241014144622.876731-1-david@redhat.com/ > With the following cleanup in mind: From 9fbbff43f725a8482ce9e85857316ab8484ff3c8 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Tue, 15 Oct 2024 11:07:43 +0200 Subject: [PATCH] s390: use !dump_available() instead of "!oldmem_data.start && !is_ipl_type_dump()" Let's make the code more readable: !dump_available() -> !(oldmem_data.start || is_ipl_type_dump()) -> !oldmem_data.start && !is_ipl_type_dump() Signed-off-by: David Hildenbrand --- arch/s390/kernel/crash_dump.c | 2 +- arch/s390/kernel/os_info.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c index cca1827d3d2e..fbc5de66d03b 100644 --- a/arch/s390/kernel/crash_dump.c +++ b/arch/s390/kernel/crash_dump.c @@ -609,7 +609,7 @@ int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size) u64 hdr_off; /* If we are not in kdump or zfcp/nvme dump mode return */ - if (!oldmem_data.start && !is_ipl_type_dump()) + if (!dump_available()) return 0; /* If we cannot get HSA size for zfcp/nvme dump return error */ if (is_ipl_type_dump() && !sclp.hsa_size) diff --git a/arch/s390/kernel/os_info.c b/arch/s390/kernel/os_info.c index b695f980bbde..09578f400ef7 100644 --- a/arch/s390/kernel/os_info.c +++ b/arch/s390/kernel/os_info.c @@ -148,7 +148,7 @@ static void os_info_old_init(void) if (os_info_init) return; - if (!oldmem_data.start && !is_ipl_type_dump()) + if (!dump_available()) goto fail; if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr))) goto fail; -- 2.46.1 It looks like we create /proc/vmcore, allocating the elfcorehdr essentially if dump_available() && (!is_ipl_type_dump() || !sclp.hsa_size). So in the condition, we would have previously made is_kdump_kernel() happt *after* the fs init calls. So I'm wondering if is_kdump_kernel() should simply translate to dump_available(). It doesn't sound completely right to create /proc/vmcore for "standard zfcp/nvme dump", but that is what we currently do. I would have thought we have that special zcore thingy for that. So I think we should either have bool is_kdump_kernel(void) { return dump_available(); } Or bool is_kdump_kernel(void) { return dump_available() && (!is_ipl_type_dump() || !sclp.hsa_size); } I'd prefer the first version. -- Cheers, David / dhildenb