From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793831195; b=oaZVPd7cyqiXLm9DYj4vT56WHusZb/rHeXUiSnGZixkkqAy48nX2g2ZlrBYG9ExT6Eyu Amc/UPLJjF/zYavSBOjMeqUVXhNuMLECH4bF++qXcr5VkFjKhg/ZVMzEI5ytM9e5tk+Vw iLemybEZo9ATIGwvupLwhL7jbVofOg4pRC+F2Oi9KHMd0V4Oe77A9j3SMDG3fHLuS74K5 7OXtrARYWta6biNhCHv4EsGbx6rsYbOn7Cp5OJOzndyaqjA8Cc1v6LnMA284Vn4JfOMQr 8XIUjI54D35G9c8uMjcTuI7W60VrHB8JxyVhNv4kN1MEA1EbD3GyoR5wniLK9x+eQvg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831195; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=vh0qKmXVBFsoTL4A0DbsTfTuhX+kJosQKOcCnRNbE/s=; b=WaaXUEb9cTK9S9y9bubUfDcRAA/HGQKNtf4JiCm42M9ENmGEW3+GA8kZSQSfiwua+t6l xljti565hYiyxOTRYFoG2VjLUeeIHcTlLM1X0fbHZF0mKTWOV5ayAoEosmV7hEB237n1e APGufpUeL0RSnEybekvjWGzpGOQEx+kG5YU/FiCYLgpny+egluQYrdpi7BWa/cDkvpP0o 7Bu6MIfr8SrcWmQEIhINcQ9cq4xHvrI6MOoAx/CiTh3rpbxehCRFaEEUmKB7KtFRzrXqx B1Ts1n8Lhejwm851eDdeEhrEAvQDFHmEbC4EmMx5pBNxoLy1hIeqRIxFGPoEtWiNM2Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=fiFCusQx; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 084DC606E83C; Wed, 4 Nov 2026 22:26:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=fiFCusQx Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D2F41F000C1; Wed, 4 Nov 2026 22:26:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831194; bh=vh0qKmXVBFsoTL4A0DbsTfTuhX+kJosQKOcCnRNbE/s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fiFCusQxASLIIoFu22Z0XXtKpy1jmrFH2jNxFuhNjQyg4+0psYVsBEzrAdcTF36LW Go2qrhWYlFoCLOZ6IC/WG6+4W6ZEnN4z7dQZnz8+2hnBVeLPfc/+avbMIZinxGip9P F3dicdYqX+g/XCuSmNfO2atpMMeI74OQLORZ90g4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Breno Leitao , Catalin Marinas , Oleg Nesterov , Davidlohr Bueso , Lance Yang , Qian Cai , SeongJae Park , Andrew Morton , Sasha Levin Subject: [PATCH 6.18 0557/1005] mm/kmemleak: stop the task stack scan early when interrupted Date: Wed, 4 Nov 2026 16:04:50 -0500 Message-ID: <20261104211059.495999083@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Breno Leitao [ Upstream commit eb11f56eeca56069613d00bf623607e305b271d9 ] scan_block() already checks scan_should_stop() for every pointer and bails out of the current block, but the task stack walk cannot tell and keeps issuing a separate scan_should_stop() between every task. Return that status from scan_block() and use it as the task stack loop condition, so the walk stops as soon as a scan is interrupted. Link: https://lore.kernel.org/20260615-kmemleak-stack-resched-v3-2-acecd7d7fd92@debian.org Signed-off-by: Breno Leitao Suggested-by: Catalin Marinas Reviewed-by: Catalin Marinas Reviewed-by: Oleg Nesterov Cc: Davidlohr Bueso Cc: Lance Yang Cc: Qian Cai Cc: SeongJae Park Signed-off-by: Andrew Morton Stable-dep-of: 3541a2b06ecd ("mm/kmemleak: report RCU-tasks quiescent states during the scan") Signed-off-by: Sasha Levin --- mm/kmemleak.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 452f3714f337b..b5e1a493f1462 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1518,22 +1518,25 @@ static int scan_should_stop(void) /* * Scan a memory block (exclusive range) for valid pointers and add those - * found to the gray list. + * found to the gray list. Return non-zero if the scan was interrupted. */ -static void scan_block(void *_start, void *_end, - struct kmemleak_object *scanned) +static int scan_block(void *_start, void *_end, + struct kmemleak_object *scanned) { unsigned long *ptr; unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); unsigned long *end = _end - (BYTES_PER_POINTER - 1); unsigned long flags; + int stop = 0; raw_spin_lock_irqsave(&kmemleak_lock, flags); for (ptr = start; ptr < end; ptr++) { unsigned long pointer; - if (scan_should_stop()) + if (scan_should_stop()) { + stop = 1; break; + } kasan_disable_current(); pointer = *(unsigned long *)kasan_reset_tag((void *)ptr); @@ -1543,6 +1546,8 @@ static void scan_block(void *_start, void *_end, pointer_update_refs(scanned, pointer, OBJECT_PERCPU); } raw_spin_unlock_irqrestore(&kmemleak_lock, flags); + + return stop; } /* @@ -1698,6 +1703,7 @@ static void kmemleak_scan_task_stacks(void) { struct pid *pid; int nr = 1; + int stop = 0; do { struct task_struct *p = NULL; @@ -1716,13 +1722,13 @@ static void kmemleak_scan_task_stacks(void) void *stack = try_get_task_stack(p); if (stack) { - scan_block(stack, stack + THREAD_SIZE, NULL); + stop = scan_block(stack, stack + THREAD_SIZE, NULL); put_task_stack(p); } put_task_struct(p); } cond_resched(); - } while (pid && !scan_should_stop()); + } while (pid && !stop); } /* -- 2.53.0