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Wed, 18 Feb 2026 09:44:30 -0800 (PST) Received: from [127.0.0.1] ([99.196.128.5]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8cb2b0e12eesm1872969085a.15.2026.02.18.09.44.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Feb 2026 09:44:29 -0800 (PST) From: Jens Axboe To: io-uring@vger.kernel.org, Pavel Begunkov Cc: netdev@vger.kernel.org, Kai Aizen In-Reply-To: <364c2e7d4f53b26bb3133cfc4271183fcd450be2.1771435883.git.asml.silence@gmail.com> References: <364c2e7d4f53b26bb3133cfc4271183fcd450be2.1771435883.git.asml.silence@gmail.com> Subject: Re: [PATCH 1/1] io_uring/zcrx: fix user_ref race between scrub and refill paths Message-Id: <177143666453.514340.3486576920762114601.b4-ty@kernel.dk> Date: Wed, 18 Feb 2026 10:44:24 -0700 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Mailer: b4 0.14.3 On Wed, 18 Feb 2026 17:36:41 +0000, Pavel Begunkov wrote: > The io_zcrx_put_niov_uref() function uses a non-atomic > check-then-decrement pattern (atomic_read followed by separate > atomic_dec) to manipulate user_refs. This is serialized against other > callers by rq_lock, but io_zcrx_scrub() modifies the same counter with > atomic_xchg() WITHOUT holding rq_lock. > > On SMP systems, the following race exists: > > [...] Applied, thanks! [1/1] io_uring/zcrx: fix user_ref race between scrub and refill paths commit: 003049b1c4fb8aabb93febb7d1e49004f6ad653b Best regards, -- Jens Axboe