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Wed, 24 Jun 2026 09:30:08 -0700 (PDT) Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 24 Jun 2026 09:30:05 -0700 Message-Id: Subject: Re: [PATCH RFC 0/4] memcg,slab: kmalloc_nolock() fixes From: "Alexei Starovoitov" To: "Harry Yoo (Oracle)" , "Johannes Weiner" , "Michal Hocko" , "Roman Gushchin" , "Shakeel Butt" , "Muchun Song" , "Andrew Morton" , "Vlastimil Babka" , "Hao Li" , "Christoph Lameter" , "David Rientjes" , "Alexei Starovoitov" , "Pedro Falcato" Cc: , , , X-Mailer: aerc References: <20260624-kmalloc-nolock-fixes-v1-0-fdf4d17351dd@kernel.org> In-Reply-To: <20260624-kmalloc-nolock-fixes-v1-0-fdf4d17351dd@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 71DBE8000F X-Stat-Signature: zuy8ffocqw6mrnddbuo7zfwxqoxs6s18 X-HE-Tag: 1782318611-106414 X-HE-Meta: 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 tgVizJ4x QgDrkqc6LI4wMpTu/as259/+YrpSX0r2jSyhe2+fp//DprUhUY6343Hc5b6eZu2HWNEz+SwhHKNzsZ9yW1YTCNj+rvPJxaINPttyFNsCJDNopTTEg8/qqWFNmMl4kdWohgqCh+HW2WVRdG4OMAhaBASag6APqiPjGGZ9IBVqJxhDYcMKEiE7D+F4+cmCDjJ/RH3IMT/3gCa/pgh7/nehijc7/YTJo82b+F31T7osVgixFfQYxz6p/ljJFhj/AsBxPpPRSgdy5MlZDejs1AZN453GS1AzCqEEMgn/HEyYXsJmmYNRIt3L4hH//Aih+l6IZxKgD/fy1MJ/qhMs3ELWrjz+BocgvkF0b4v5Vl4KQdjnhbpG2ChpavrXwVQSIewYC+XceDBZqa14U/8SluuJPO9njsmQzYsinLUBvXCneQFvU64hUESOlTfHhzAC64BlIff4ZqXd4SsFB3qLo+MnIWT/taWEhzYHVLDO6wejW9PgBLye5rbD32a7TDHSxIv3OmzosolqQ/sEENkdsUMO7nDqRInnhMn+510t4rckmmHzz0k5EyfbRYT2cpcOHzkgEmH9cEysDu+QW161n90DcMjlHB8WXYRzr5lFZIkOMJOWnDK0cqp4iLhNZ+iNcSP2o8x+T Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed Jun 24, 2026 at 6:11 AM PDT, Harry Yoo (Oracle) wrote: > > Bug 1 was reported by lockdep, and bugs 2 [2] and 3 [3] were > reported by Sashiko. ... and in fixes for sashiko complains sashiko finds more issues. I don't think it will ever end. I suggest to fix realistic scenarios instead of one out of billion cases that sashiko think is plausible but will never be hit in reality. The chance of server crashing due to cosmic rays are higher than such bugs. Hence do not fix them. > To BPF folks: do we need to backport kmalloc_nolock() support > for architectures without __CMPXCHG_DOUBLE to v6.18? nope. > There are still few users in v6.18, but I can't tell whether it is > necessary to backport it to v6.18 (hopefully not as urgent as other > bugfixes). imo none of these 'fixes' are necessary. Humans are not hitting them.