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 447294CCDC7; Fri, 4 Sep 2026 05:38:04 +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=1788500286; cv=none; b=XAtbnM7fAJfYe1KQWXggh78cYRHYCa9Tukal+RAAdq+yMb+Dqw+rRZXzoCz2C7Oi6prnuNNX7trvzFo1Qwf+5tTbeiEz8XGtXJGhfrtcknLZCgswW7cHrBqBzg8ba6n0YpREC2/hUa8mVhB6RquBvfiCBXm7l6I3Ds6HIaKQ4to= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788500286; c=relaxed/simple; bh=ARXIecUWJisEVPabMYagT7Ld0qW4YRYH+LbDNPQsNnc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Cec0SMjNKTv/5cZyCpNBPFgnDuhBNN3OjgskeedqHPk0ODmSnsYUtVzjxBus/w5cjdHAq9LTB2ux89Jm9hwq3G22wu6mAdkCL7g6z7JitYMVTsZ2GOjYFxJzzRuEy+Gdt0+uFAqd4CSnGT+RHPR+qNpEkR/6ORjk1rP4rmgS9fY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HXIL5zX1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HXIL5zX1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5F3F1F00A3D; Fri, 4 Sep 2026 05:38:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788500284; bh=5s3TYO5qVHmrQIKuDiw1Gbca13mHlenMKklToxVCJpg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HXIL5zX1WyiDl2BzO7PNTZFUaQHzGDvhdu3LlstkH4fNlnIf6O45g0q+9Uwg9UL3/ p6J45IJXmwAv5Jv5hdVThMFApUrlBqRoBSJJwExNdit+6uMjVlJM4EDl9y+ieqDZoX GvG6kuMsrm3630obzjTxr6jPjX7HXOERDHxHofPY= 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 7.2 683/713] mm/kmemleak: stop the task stack scan early when interrupted Date: Fri, 4 Sep 2026 07:00:51 +0200 Message-ID: <20260904045819.150125416@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045803.810145556@linuxfoundation.org> References: <20260904045803.810145556@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-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 Signed-off-by: Greg Kroah-Hartman --- mm/kmemleak.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) --- 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, voi 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(vo { 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(vo 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); } /*