From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 83CD32FE571; Thu, 8 Jan 2026 02:35:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767839715; cv=none; b=p0cxuNmbpDzHadX5LQ+4sA6KDAN5Ypxv0ryDeg9xJhApZ/Z7xUMhjUBL4yZDgbpJa160yCXLAy/Jl2F3a2UPFYTenKBz/fGDfFsIqi19ZVvjOUUQp/zu1Of/JE3k1+kQGLeUZE+yAPfeZywSMYfV8nftdPeKAHESCDwJS7EJ0LY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767839715; c=relaxed/simple; bh=mwO0h8pxODHcoTt8zbXiEQOPVm+2tOSGeyNuIN4895E=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=CFxCSS13HR5btuoV0cUoJXEnhrHMIP2/UjX6NfV6Bom87pJNxQrenhjcPPjHaKkcxgVwDw8Q4MzTa5/N7FsX3VfZ/ATyKlJ3ki1dyukURi2frmtZmEWftj75M3gXNcHPUYKC+d4jJbxNLNR9hepoGEuOnytIbC75N3zqRY/bgkg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RJ8sf8Wp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RJ8sf8Wp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81BE9C4CEF1; Thu, 8 Jan 2026 02:35:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767839713; bh=mwO0h8pxODHcoTt8zbXiEQOPVm+2tOSGeyNuIN4895E=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RJ8sf8Wp0rux6r70tlzGDqyyhXtmcBsDiHnDz4jroLF+C0FLPK+kB0Jhd5DNbXhuw FSBt6lG3uvBrRstujmtSAvOvW7IKtci2XXpFIMTR2W4eZfzBgXrbMhMELvkH78SqI8 pkCBEK7tBUWL79E3wNKZ72fNkcJR52NgkMtoOuRSOwec04K4UUXAF+M1PHaNXkcg1p 4l2hE0eLb9I4nt+0oqn5JaxM6tr5TMRsFjfr8mbu/xPXFQrKG2rA1Mu6WWooIVtzZF qL4domMDl+PVRO/Z3FOoWcDTeM46svN8Tlmo1Im8ish7yh+02l5cHpr7ZB4iNJ9e+s oxrERWNWFK3bg== Date: Thu, 8 Jan 2026 11:35:10 +0900 From: Masami Hiramatsu (Google) To: Ian Rogers Cc: Steven Rostedt , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH v2] tracing: Avoid possible signed 64-bit truncation Message-Id: <20260108113510.5f0716c539f2ab416fd39ec9@kernel.org> In-Reply-To: <20260108002625.333331-1-irogers@google.com> References: <20260108002625.333331-1-irogers@google.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 7 Jan 2026 16:26:25 -0800 Ian Rogers wrote: > 64-bit truncation to 32-bit can result in the sign of the truncated > value changing. The cmp_mod_entry is used in bsearch and so the > truncation could result in an invalid search order. This would only > happen were the addresses more than 2GB apart and so unlikely, but > let's fix the potentially broken compare anyway. > > Signed-off-by: Ian Rogers > --- > Reduce the number of checks as suggested-by Steven Rostedt > . > v1: https://lore.kernel.org/lkml/20251209224024.2322124-1-irogers@google.com/ Look good to me. Acked-by: Masami Hiramatsu (Google) Thanks! > --- > kernel/trace/trace.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 6f2148df14d9..5e2d597b4377 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -6109,10 +6109,10 @@ static int cmp_mod_entry(const void *key, const void *pivot) > unsigned long addr = (unsigned long)key; > const struct trace_mod_entry *ent = pivot; > > - if (addr >= ent[0].mod_addr && addr < ent[1].mod_addr) > - return 0; > - else > - return addr - ent->mod_addr; > + if (addr < ent[0].mod_addr) > + return -1; > + > + return addr >= ent[1].mod_addr; > } > > /** > -- > 2.52.0.351.gbe84eed79e-goog > -- Masami Hiramatsu (Google)