From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D31514F55D1 for ; Thu, 3 Sep 2026 17:49:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788457755; cv=none; b=jMotaeCZZMQ+t6vrh12omEPg1vvhhuBnMRBvUDR2nAchB3wnJn69Y1Y/enhsgKfc5L/wryLxpZnO+Kwop+Y49MOBxtypyQqenOWb4GU+4d1B6Gr5teWzg8MfBjtoUEAWQCW9npI/VBFm7f5n6D7JcTYMfkceigI+IopM86vxh78= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788457755; c=relaxed/simple; bh=kfBoMBK+znh/ZONgx+wRUvYoTdZo9ludfC8gLBVotXI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XWXAhArIcPsWhEoQn9wajZno//G5/AaR/HeIu7LERpyx2B+WvlyyQsg2HWJStO14I8ouYwMCcWm9te1wA0rLBAehJt8ZnpKHy+ZlwkM8yXL99q6GxzoUVQo4E8hnk9Aayti6eobbQ/+19lzz5I/CSr/VhmWnSSSEr9WXlYwGKpI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dJTCnIeq; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dJTCnIeq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7919C1F00A3D; Thu, 3 Sep 2026 17:49:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788457753; bh=YoGE/GZnm0huTJALyUQRn8iOJtkBLr0I6Vcvq/v7jYw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dJTCnIeqrcRajZN/RbRKIroYxF+FtxDon+XwPQlregZ8t+uKBblwjeuttzsCqz5gB oi2eZ5epi9gc+nal8v5yARVcOXZryX41fwYPyfGa+oTTPdlqumOmf/zaxnSIiYm9Hn mPXlZBqN6f2q1FZvNF+o3sGB0GfXLaKlVpKqaZ/QVPRUCrDQC5IASQv25WDpiHXYM9 pyG1fU8LsQyIw1HSR9OciJZMXmcK/Rl61/5F+AwhMQtt5mUYpX1tu4SYxDailn3M7U 2bv2Hy0cM1tC/2NYAxyXnzfUN6DjNkxlA5Vxtz9AZsG8S7fMSjViBOhzMvL7L28lcJ aRM509MN9SwvQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Breno Leitao , Catalin Marinas , Oleg Nesterov , Davidlohr Bueso , Lance Yang , Qian Cai , SeongJae Park , Andrew Morton , Sasha Levin Subject: [PATCH 7.2.y 2/3] mm/kmemleak: stop the task stack scan early when interrupted Date: Thu, 3 Sep 2026 13:49:07 -0400 Message-ID: <20260903174908.1268466-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260903174908.1268466-1-sashal@kernel.org> References: <2026090344-tightly-handiwork-36ab@gregkh> <20260903174908.1268466-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 16b72cead07d2..bc79e293531b7 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1525,22 +1525,25 @@ 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); @@ -1550,6 +1553,8 @@ static void scan_block(void *_start, void *_end, pointer_update_refs(scanned, pointer, OBJECT_PERCPU); } raw_spin_unlock_irqrestore(&kmemleak_lock, flags); + + return stop; } /* @@ -1705,6 +1710,7 @@ static void kmemleak_scan_task_stacks(void) { struct pid *pid; int nr = 1; + int stop = 0; do { struct task_struct *p = NULL; @@ -1723,13 +1729,13 @@ 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