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 AF53439BFE2 for ; Wed, 13 May 2026 10:24:41 +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=1778667881; cv=none; b=ui48jziFXdNqzUxYQYMsNTBNWVNXvoowe1H2RaS+QoD5CJX6704TQtlEF0XdMrsvXGFLP2y0K5wawmeHPzqw1PwhekOdm7dbofc8Wi9t+pB2li872v4uvuaUiBMt3y1XGw/HEFXGXQqopFxb2MiWqVjRWDalbSqT6Szcuup2C9w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778667881; c=relaxed/simple; bh=nRj/ZOMJOwQ3eYN8qoWo96aWvkfgzk6m6kyfgL1dzr4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=F+2wMSuWThLhtptnsOT/GwZrecvFznmLoPUGNWEV77FatbuU+DEDC/Taf5GXWKbC3Ec7wKejgnRLiAi7Ve0jkClyCCUWDdaWg1nva+v4i89oFKniimIJHVUh18y8dohPCrepd7OZ1Ny/c5mVi8H4ttwWzxos8dl8ZFZF5QChjXs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Bna+1el4; 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="Bna+1el4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2E73C2BCFA; Wed, 13 May 2026 10:24:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778667881; bh=nRj/ZOMJOwQ3eYN8qoWo96aWvkfgzk6m6kyfgL1dzr4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Bna+1el4eb1zN7Scsid60/Qy5eka2UlXtxe/Z/p6OQxqIOTtR4oywr/zwj7NGxOyX 1z1D5jpFc6vy69NQdMbOnSeWnHW6tYC3NKlkAzPVngHwCVR6+wrTYrfiYkdok92oMI NAAwVM/EGhZIy2ua7TD+RE4KiBDebnrCAUKGKqaPqWDjrMwXV6Uag1iJ92P+fozkyP abmAe2T3FTbDqZOIAHQufmgJsn3C4QQMz+8m8fJ0gKoIuQ0mlRphPluMOfpoe6f+eO Y8Kl2q+J8Y70xEg6kl/JPrCeTBUhMH1GIwBHsBVpgQC8vgzCNK7WFlVbzeXNG6z8Mn SwZTnOu3MG5dA== Message-ID: <1b81b2d8-d9e2-4c51-b475-785989aa81b1@kernel.org> Date: Wed, 13 May 2026 12:24:37 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] tools/mm/page-types: Fix ternary operator precedence in sigbus handler To: Ye Liu , Andrew Morton Cc: Ye Liu , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260513022120.58033-1-ye.liu@linux.dev> <20260513022120.58033-3-ye.liu@linux.dev> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/13/26 04:21, Ye Liu wrote: > From: Ye Liu > > The ternary operator (?:) has lower precedence than addition (+), so > the expression `off + sigbus_addr ? sigbus_addr - ptr : 0` was parsed > as `(off + sigbus_addr) ? (sigbus_addr - ptr) : 0` rather than the > intended `off + (sigbus_addr ? sigbus_addr - ptr : 0)`. Add explicit > parentheses to ensure the correct evaluation order. > > Signed-off-by: Ye Liu > --- > tools/mm/page-types.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/mm/page-types.c b/tools/mm/page-types.c > index 6594245217a8..66f429f2b698 100644 > --- a/tools/mm/page-types.c > +++ b/tools/mm/page-types.c > @@ -1000,7 +1000,7 @@ static void walk_file_range(const char *name, int fd, > fatal("madvise failed: %s", name); > > if (sigsetjmp(sigbus_jmp, 1)) { > - end = off + sigbus_addr ? sigbus_addr - ptr : 0; > + end = off + (sigbus_addr ? sigbus_addr - ptr : 0); > fprintf(stderr, "got sigbus at offset %lld: %s\n", > (long long)end, name); > goto got_sigbus; "sigbus_addr - ptr" will give us the offset into the mmap(). Adding that to off will give us the offset into the file. No idea what happens if we don't have sigbus_addr ... Anyhow, your change looks good, I just have no idea whether updating "end" here is the right thing to do. -- Cheers, David