From nobody Fri Oct 3 14:34:25 2025 Received: from mail-lf1-f41.google.com (mail-lf1-f41.google.com [209.85.167.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E19D42D12E4 for ; Fri, 29 Aug 2025 11:44:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.41 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756467886; cv=none; b=U1aAGkKgZDpYMJKl12Pxla4ZmnxzW5aqXK2WfsAozkM1hnG2Z/Kc6qIJAZ+RS5lNA+WOLUnUpbVI6y2duHe5jeDkRETWFVHNAAJ98bW+oiyxxbVPH/YeVXaeYEbeczoMeqCXnzDdvJtfh756bUMpojYJ2QGeL22CDSFTphtVYpw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756467886; c=relaxed/simple; bh=eWdD+y64i88LvocVzHNcRlj3EFHUTHNycTJjSnMmtPg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=IlhfL0pzg5HSDy5kPG6rqjX2YDa1xGU1i2ilFgCyFCr2p57rE2Z6IwWW9P4B6mdOvmWGEaX9ztMLgl/fUSrhcCRkiq0FB2C7/G6uUezH0cFSu+zBLQg9OWgfM4MQ+El5AKF+tBHYNSUb+YQ6DXnS/3YdTNOzpgCjr9/Mub3tuso= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org; spf=pass smtp.mailfrom=linaro.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b=RZq87Ykh; arc=none smtp.client-ip=209.85.167.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="RZq87Ykh" Received: by mail-lf1-f41.google.com with SMTP id 2adb3069b0e04-55f4345cfd3so2090508e87.1 for ; Fri, 29 Aug 2025 04:44:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1756467883; x=1757072683; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=jgtia+LpfMpm3WYDNDpUT/QXDK2dR0NCJT/wLTvQl3g=; b=RZq87Ykh4LrzLmDN60oHigVQXCn77ovpKUTFWOfPXxfeqcNco1GfI+H9UXNDaOA14N a0581FhSHb1t7kVXZzeg7jyfN31bycgN5XjWx97Z4JDd3o4fhFzPd3YsUar43S62ZOPq lTSp48CeuPlSUL16C9AbpLiLl64L4Ue3cU4w8J+Gxkm0B1CzFNYpY9M/Q/2ikasEt4m2 z/bOzKdcSGv7y0v1GrUI3292Iofc5cI8cvSqTNclwVTDAWgI864wu0/NemTq+5nDT9kV MycREZvCABTCK6YUq0uVIsllwRYOTsyfs0dvpFpEg2hQ1VOP9T/c9sbLr5Wbs2aQy3SK LfhA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756467883; x=1757072683; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=jgtia+LpfMpm3WYDNDpUT/QXDK2dR0NCJT/wLTvQl3g=; b=L7rTYXaiBMXvotcJlCM0pFao8OPdKwMx4FTVNFADjuIbOhI8RGtbwFLoKyrisrsgnw /GkXzp6n/q491zkcOWHZusWMeC83A/5cC+sbs9XBnn98jL3olzPk9pgebGRywsiHKmpm 9BhETiGtUVMs+QvjCp1u6aT3arHQzK+JX6EyXK4a17WmPAdv9zpQtJFo8Fwp9eU4nJcc mbwl3g32HC2MfSpg3ZEPSOLYvaRP4ugpIZTNMkZlF3yiuNWG1NfgOzoURPJcTB5sDciz D8cAGVOLzyFNa3DNJF5uLM0DpIOt4K+c3SZOj1j+ievHJCubYDgIZ9k6PDIpNyUXNYqx Udfw== X-Gm-Message-State: AOJu0Yz5xvonETCOGr68nbSvGkrhRTOkLqXJlUN8982JtaTFjGo4D5tk xBMvxx9uV1A4RrooB0mNJKMc9YVE24AcZydm9EjocyjUK04tzRIVvpKgiqHNsXIn7lI= X-Gm-Gg: ASbGncssrWa1+VQt4SjUbj9Nu8raahxHiwyGE7e66XS9a9c1mI7l2/f0MwMf9kwJqSK 8pEYkNg/2DHqWnuAajbu6ZngynGS7ddVeAHmPqWF6dBicBNoprYYcm1xG7nRC09vvi7rnRSaGyt CJh3EtQunJZsbzIXGYJp9pGftMhOZe5RFjN2Yb79InRfG1+I8svnCKVEjpnKKlwn8L5YgAIKuT+ YuB1XgPqdrZCgcjAQxVw6rFWKCGcosa6JEEF8JYx2xLIl6ZgFYNgw38beg0Vn0dtPFP6jfzErxD Hh/qFHW1NDm5F8JouBU3zA672H7ZCMX4/3ewT3wBZvE5Vk+AfeuqTfRq6vXaet33xEULI2mCQVe amUI+BzmdHk3iMgHrP5FtCECkUKAqZEoj X-Google-Smtp-Source: AGHT+IHAqQsoVsR6L7a6rcLo6fKDNuhsLtvlWrPRnW+IIIX2gb7KKe3MHpJzSG95OBA3WhmSJVm61g== X-Received: by 2002:a05:6512:12c4:b0:55b:84d3:12b9 with SMTP id 2adb3069b0e04-55f4f4c6a38mr4346175e87.18.1756467882843; Fri, 29 Aug 2025 04:44:42 -0700 (PDT) Received: from [192.168.1.140] ([85.235.12.238]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-55f67a4c612sm581162e87.146.2025.08.29.04.44.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Aug 2025 04:44:42 -0700 (PDT) From: Linus Walleij Date: Fri, 29 Aug 2025 13:44:40 +0200 Subject: [PATCH 1/2] fork: check charging success before zeroing stack Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250829-fork-cleanups-for-dynstack-v1-1-3bbaadce1f00@linaro.org> References: <20250829-fork-cleanups-for-dynstack-v1-0-3bbaadce1f00@linaro.org> In-Reply-To: <20250829-fork-cleanups-for-dynstack-v1-0-3bbaadce1f00@linaro.org> To: Andrew Morton , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Kees Cook , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Pasha Tatashin Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Walleij X-Mailer: b4 0.14.2 From: Pasha Tatashin No need to do zero cached stack if memcg charge fails, so move the charging attempt before the memset operation. Signed-off-by: Pasha Tatashin Link: https://lore.kernel.org/20240311164638.2015063-6-pasha.tatashin@solee= n.com Signed-off-by: Linus Walleij Reviewed-by: Liam R. Howlett Reviewed-by: Lorenzo Stoakes --- kernel/fork.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index af673856499dcaa35e135a9e8042ef28d5c5370d..2a5b7a5fa09b1f3a42473cf44a1= 316ec8b3b31d0 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -290,6 +290,11 @@ static int alloc_thread_stack_node(struct task_struct = *tsk, int node) if (!vm_area) continue; =20 + if (memcg_charge_kernel_stack(vm_area)) { + vfree(vm_area->addr); + return -ENOMEM; + } + /* Reset stack metadata. */ kasan_unpoison_range(vm_area->addr, THREAD_SIZE); =20 @@ -298,11 +303,6 @@ static int alloc_thread_stack_node(struct task_struct = *tsk, int node) /* Clear stale pointers from reused stack. */ memset(stack, 0, THREAD_SIZE); =20 - if (memcg_charge_kernel_stack(vm_area)) { - vfree(vm_area->addr); - return -ENOMEM; - } - tsk->stack_vm_area =3D vm_area; tsk->stack =3D stack; return 0; --=20 2.50.1 From nobody Fri Oct 3 14:34:25 2025 Received: from mail-lf1-f43.google.com (mail-lf1-f43.google.com [209.85.167.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7D4E2D3725 for ; Fri, 29 Aug 2025 11:44:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.43 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756467887; cv=none; b=PdoXMmnnIteVAjqUtRjds1Vl624ZDK0YN/j5ZmBhGhtV61rkQIJICMhVNuoJamT55BfhGP9P7uUotW1gTfbXr0O43Ng/ljy2ia/qoouMJFp+r+47tDi4elRzBc1c+9nWQY7NxC0b8SanyimaoxfNmO081FeLTteHWosaMkst59Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756467887; c=relaxed/simple; bh=y1oaiC2Vzo0cWINY8w/DPK8Tfo28TPudIZiSmEIyJUA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=b0Hd8LYic+RX+Fu33Y3lIU96Qvm47M44au8gLLkC6lNzVdZpxqAg7Njua1BLJje/usEZs+oim0Qlp0e1cCgfhqT2OHdXdDCEoswo4pRdCC0sobkhRMhR8U0wwenthJq5rlE0DIKAQwTJJzRV9PvX5cGaozY7tm/1CXAULBizSzo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org; spf=pass smtp.mailfrom=linaro.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b=lXYPz+Ok; arc=none smtp.client-ip=209.85.167.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="lXYPz+Ok" Received: by mail-lf1-f43.google.com with SMTP id 2adb3069b0e04-55f44d5e6f8so2082488e87.0 for ; Fri, 29 Aug 2025 04:44:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1756467884; x=1757072684; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=WFe1CktsVDIUFXMUlAWVFSXINqaL27dLXjci6lesYis=; b=lXYPz+OkK1n8/0iOvAWk1Z0lhuJwYFPM7rBuv7Qj4unNnW5Fdk+xGDzYF6NcJoD5gr 18YZ6Nmpb+Nw0P7tAPAKE/+Aw7RX+SkVKC5JhZZljm563CBRZ0A2AYTSkyAniFSg0P9G +K0xDjxp5e4AJae36HAZwv5QxAzNlRqOwfIrqGWEhs5vVHuz/6WONW3dE4/ljJIe3CFt DQj5RThMvgdcvDUyoBXVsKJ/oouHkayEWlq6gkluoN7WdT7vLFJAk6fKmg2PHIwoUAxl oq18LNX0aGNXCrAQam0J2o77HXWpYxNju1tAaCK9n2F/QY/hcj87IufNlmrC46EyjW0I 3D0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756467884; x=1757072684; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=WFe1CktsVDIUFXMUlAWVFSXINqaL27dLXjci6lesYis=; b=vjJnjhFI4uL76dvZJmW08xnU00Q7qtL0azrODiIUFVQfXQrrIkMbkssapDklQUxK/G HZbWNzqYLGIPeQa8WDgFvv1V6H6Vliw4RwP0KIcep+mXsG/7Yr5T5G+Zw8lbSnWZ4fxO gsGtukpRGoOfllizCgHpudgeJW1S/f2v3e3Q/mRgUYT0W3HsnCRp4022IiXlkmSe7zKy T2d/y/05044SfLANoZvm7JwjjCjXZ1wEmXj/E5zzYiCt20jojikf+uMN+wnvnnvlnWY8 dr2PCIIda8Vxt7fIt/LDwn/fSxSv0FLRwK+GBW/bgFCjrtU91/9WsqQISGgnhcfHH3eo Tk5g== X-Gm-Message-State: AOJu0Yz+EDQ17CLWlcX5REkvcZQC7gK+rFN0u4pz5NvX/Ans8dRkJgyQ m5ZaVdJhorGLt/c/ai8YME8pSKEok7DT+cKa1KqjVxJqD555A6G4CYqJfqyu24h6x4o= X-Gm-Gg: ASbGncvG7uR9yDbHpBvVm10Uw7lhAtLqtiuT+a6DJ+C4LCFqOQHOyNOOREz9MPHoScY Dbd0YOXqoRctCK9sX3ySPONeYdZpTLjzySY6hr6dVuydQVBU/3poeVjAEyHuJfGLAWN3+xVWILp +uYYd43QnsnsLKh9yOkfB2+gLpk9agEirg6bqIs4R3242OOepzVIOxNJSoNi9ea1+okqNUMDBe9 dofzousfxaJh7GwjivXQa0nqb3A+SHR7AkRCUtD57DweOfmV55DAOREA0FU17asYPFvjjY8sVyk vjxBdKZQjYtQKNFO11TthQUYz0dT+CoDR+eOVPzLtXVRp2dxBKI/9Ke+zsEdF4UEWrTUn9h8Wye X5CVf3us/mId+xGC7fzot7Q5HTiMT4qhbLzYATyQXnKI= X-Google-Smtp-Source: AGHT+IEkHsybnNaIxaBFEfVj1kIY3d3G3hiLCzbN2/ndqe/LdNG+/k5r6X74sVsHOJsMfoa47sH13w== X-Received: by 2002:a05:6512:6703:b0:55f:449c:19e7 with SMTP id 2adb3069b0e04-55f449c217emr4969600e87.55.1756467883912; Fri, 29 Aug 2025 04:44:43 -0700 (PDT) Received: from [192.168.1.140] ([85.235.12.238]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-55f67a4c612sm581162e87.146.2025.08.29.04.44.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Aug 2025 04:44:43 -0700 (PDT) From: Linus Walleij Date: Fri, 29 Aug 2025 13:44:41 +0200 Subject: [PATCH 2/2] task_stack.h: Clean-up stack_not_used() implementation Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250829-fork-cleanups-for-dynstack-v1-2-3bbaadce1f00@linaro.org> References: <20250829-fork-cleanups-for-dynstack-v1-0-3bbaadce1f00@linaro.org> In-Reply-To: <20250829-fork-cleanups-for-dynstack-v1-0-3bbaadce1f00@linaro.org> To: Andrew Morton , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Kees Cook , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Pasha Tatashin Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Walleij X-Mailer: b4 0.14.2 From: Pasha Tatashin Inside the small stack_not_used() function there are several ifdefs for stack growing-up vs. regular versions. Instead just implement this function two times, one for growing-up and another regular. Add comments like /* !CONFIG_DEBUG_STACK_USAGE */ to clarify what the ifdefs are doing. [linus.walleij@linaro.org: Rebased, function moved elsewhere in the kernel] Signed-off-by: Pasha Tatashin Link: https://lore.kernel.org/20240311164638.2015063-13-pasha.tatashin@sole= en.com Signed-off-by: Linus Walleij Reviewed-by: Liam R. Howlett Reviewed-by: Lorenzo Stoakes --- kernel/exit.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/kernel/exit.c b/kernel/exit.c index 343eb97543d568baeb23142edcc9050a8b8be8bf..9f74e8f1c431b6aa6e391ff71aa= df9895a3857ae 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -780,24 +780,29 @@ static void exit_notify(struct task_struct *tsk, int = group_dead) } =20 #ifdef CONFIG_DEBUG_STACK_USAGE +#ifdef CONFIG_STACK_GROWSUP unsigned long stack_not_used(struct task_struct *p) { unsigned long *n =3D end_of_stack(p); =20 do { /* Skip over canary */ -# ifdef CONFIG_STACK_GROWSUP n--; -# else - n++; -# endif } while (!*n); =20 -# ifdef CONFIG_STACK_GROWSUP return (unsigned long)end_of_stack(p) - (unsigned long)n; -# else +} +#else /* !CONFIG_STACK_GROWSUP */ +unsigned long stack_not_used(struct task_struct *p) +{ + unsigned long *n =3D end_of_stack(p); + + do { /* Skip over canary */ + n++; + } while (!*n); + return (unsigned long)n - (unsigned long)end_of_stack(p); -# endif } +#endif /* CONFIG_STACK_GROWSUP */ =20 /* Count the maximum pages reached in kernel stacks */ static inline void kstack_histogram(unsigned long used_stack) @@ -856,9 +861,9 @@ static void check_stack_usage(void) } spin_unlock(&low_water_lock); } -#else +#else /* !CONFIG_DEBUG_STACK_USAGE */ static inline void check_stack_usage(void) {} -#endif +#endif /* CONFIG_DEBUG_STACK_USAGE */ =20 static void synchronize_group_exit(struct task_struct *tsk, long code) { --=20 2.50.1