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h=Date:From:To:Cc:Subject:In-Reply-To:References; b=ApP0SeYWgK/fb+hUNWApFldDRqoVoZWnQdYp+98Eoot66+GQ/gZq0cnbbDL/XwvgE V3W1g9IjjTYwLb3QcQeVGTy5qEjGi6EvCW676uRYlp4bbbITuIEuQ0F1C5S1YAO6ej 1wByCOxQX/KIo/QAyip+SmkItJm8arBhWSgt7ZL0= Date: Thu, 9 Jul 2026 20:13:02 -0700 From: Andrew Morton To: Catalin Marinas Cc: leitao@debian.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: kmemleak: confirm suspected leaks with a second scan Message-Id: <20260709201302.fb87e3bc6b2822c56856e455@linux-foundation.org> In-Reply-To: <20260709173347.689607-1-catalin.marinas@arm.com> References: <20260709173347.689607-1-catalin.marinas@arm.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 315FE4000D X-Stat-Signature: cob6hjz4zoyf8exhsb7hu3d8nuf8hkmx X-HE-Tag: 1783653184-718468 X-HE-Meta: U2FsdGVkX1/cnld+awtzCmwEemPdy0ga/hJxuAkKq5AyHhnDo43rALYI+DPrCpoK7oSl2b1o5I27xKsDonxQMNMoIaPTC2FTRPNOPah5qbiImBOQFg6+SqRw2AZrJVQkwCuxeiD5qUux0iAEyZs6q0lHt1CUsZkUvXH42IvQurvHtEwdArgpgyflKF311QR/PVdcdy9K4wSV0DBwG9GzmkDOiELO/Uu1Um9O25++ldvBBB/SFf/CMD7JVyegpOeE8h7MCEPa5qPAufkPuSbV6ZGeKVGvobGZi81pjDTQ1u1NQFi/4vZN23Jv3Q+HkrEYfSmvEz6VUglrSfdwIwN62pR41nkXWT8dKRBesmyOaOkkdSTj0HUkPjd1PbldZMT5mRzfhH8ZtdaAf6Mtxaj32tK4tDFK+d+8GvKSZzWvPaZ8/XkU3mJDbsrJeZe/hyiILOK5dnAE91B/4wrS059i8zRXIRaLZ0e560x87kTUKQr3pawmexnBrjhb6KSvZyoM/xS28IV+gxEhEQiNk2tHB3O29HpVAp2+gvrCBq3rj4YTHVRVFAiEZJDm7eyQ+XYhbMvOta6uOOZYQxhv3eAWaZkItw1+zVQxT38LhZdiU9lAy0ukqUtOdWd3Avh/fYUiNvu0cgemfeeEtryL64jyCu6LrpP7PKh6j0NKISarWyiFg+aFYHERIT8g7x1xBvwrQ2c8BNUPkMpRHFoWteoX5JGQrsyzB7GsEnZApIOxq27RBaX9AytOvnEcElbsdBQQRXLfGwM44hB4o8kII9IPnez74YmitNWr3boQYmbKTtvCPxiH4wT/lM6OpQPiCeCJpEvzlWzu7+Md9jo1+HnVw9fnv+GL6Rg8eYeBOVJrnKUb2y1fB0Ql0VhdYltDs365d2rqCNbMAKxDi063WG1exuzJFv1GY9FjSCQIV8BprZ/myLmN2Ev6kt2abyrzUw/qXjFgDVh49IF2vgKiJMU cyZb4nH2 ZHOWkv7SsddQKO9u9ws28cloUzsxvtPsX0mLSiDOagwAO2tf5YdsEEtDSQi9LdNqndStE85giVraIcpzpUr0N3EHVphQ7VQCZ66CIvqO5P1LlzBBNG3oI8BRgGSKMT5dHEPDESq3JuRjTeYxL3/odJKgiwGaMM6sR5L8QCvy6D3DSgoCsfWOm3tyzSaLtTZh7JuHWwZkJ32wnmwKw6acCSea82LAoZ+cMBYwedskbczdLtpfff9zRHUNy9U+KOWn7ttI+fB5E9Mo3bd339+ZXQR0Z9TzZuYznE/lzUALRlL9l6N9Q3ClKFF2T3yy1iq4wDpblEPxSr3RmnIA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 9 Jul 2026 18:24:47 +0100 Catalin Marinas wrote: > The kmemleak marking phase is not atomic. While the object graph is > traversed, the kernel can modify pointers, free objects or allocate new > ones. If a reference to an object is moved from one location to another, > kmemleak scanning may miss it. We have explicit annotations like > kmemleak_transient_leak() but identifying and maintaining them is not > trivial. > > Given that such transient leaks are short-lived, rather than just > reporting such objects as leaks, do another scan to confirm the > suspected objects. If no new leaks are found during the first scan, skip > the confirmation one. All sort of build errors here due to other changes which are queued in mm.git. > BTW, I'll be away from Saturday for three weeks. I may reply > occasionally but won't be able to test anything. Have a great time - we'll be here when you get back.