From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f51.google.com (mail-ed1-f51.google.com [209.85.208.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EC8903AF67A for ; Mon, 30 Mar 2026 09:52:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774864363; cv=none; b=a58kbNuSV9hJvu+pQ74V8uxAYzTSsf3lr4fXBrBDk43U7qUnBPDXhNFfOTqcKtED+U4yngUrrQp7RqthEz53CMHhiXMp94RUGl9QdmUlGq+oChhpZeIT2bTvCICHSDBrouAboRolk36AA+5QyeYwNLSc6xN3dRp53UgB6McOKJY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774864363; c=relaxed/simple; bh=I9JWL0TnRVg/zBZcrP4TkUOOuUEXZ2luMJ61hcty0oE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=TnGwuDqbDoOMqExpOFbAZOObXErDMsurFLUzmj7khLdraugYHfDG4wjenx05lhxzfm0XMtAutloQMDNnDqeHvv0H5me4jkDI8ITWjhaIkfsqrFDm3cnWgKUxsbDq++CoHej7ooodWL7BCLuWjv9+L63Po/XE9kB0r/ldNmoJCKc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=l3HOaNQw; arc=none smtp.client-ip=209.85.208.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="l3HOaNQw" Received: by mail-ed1-f51.google.com with SMTP id 4fb4d7f45d1cf-66b2f6e983bso4562919a12.0 for ; Mon, 30 Mar 2026 02:52:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1774864360; x=1775469160; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=cn7BPueizG0aOaXVcVQhQ6g9SE/PtvAJOzX0fQc+gbI=; b=l3HOaNQwnRoDqfzMKpf7olWVTGhjZn94vLmBIeQtBcg2loi+stpi9YZbvtumaZnNem dWBWCkGCD3smRdkBHauDsKNdq136oLBm5r5VRY6Kdj4XsSkAFXYuL/AauO/WU1ugRl+L va8uqZKNoA26yulNMm9p599v8tuDR2PgMRv1RcI423DW8PrQI+dH5TtL7MqlJQpXIPda v3lKbHXca3B8bYJX070aTa9bOrLG3JzZNNzjzTn8LkCCEKmvEJP6mWW9bWF/Q4epBF7u 6IrMzdZyGk98s9CeswI6RW2qc69QZ1WeM2jz642UpPkUi/hUVpw+DgsmeE6xC0RyX9W1 gFng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774864360; x=1775469160; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=cn7BPueizG0aOaXVcVQhQ6g9SE/PtvAJOzX0fQc+gbI=; b=pzYZFdBJLFQ4sGENFBIbxUcljApYXqExWxXwjqTknLBjGK/JJdUP6mbMpPcrLp+kdJ REAse1XMFYL1Kfz4Oh6+DpkOm7mEMSYzSiCDb0ycQ8dDVIadtdK0MhC1EKa7BZSJH1QW oFLoW0eqGjZSvtm6Ow4IeOjAL0QRBbuY9yPr6zB1KIOYMJXdDgazz6hvfJ+cgQ/wN6VS 8KA1rbBK26xYo5t0m3qwuyPnSIksp57a9fZfAofBnyuT9z32royHtoBs8wGNOCotVMH2 277K0eQ1DI1IvDIn/A1UW45W/yhK2iiTmkFNizzybzuT/pBSIUQzu1b8Aj9a10d5tFGJ O0sw== X-Forwarded-Encrypted: i=1; AJvYcCU3xFz0Az4ceEDghnqXvIY1Pzd+cvzDf7NTfrPeQXXJ/OvKq9zKlbw6wu9cVfzrpX2h6Zv+f1Z1LKrvkg==@vger.kernel.org X-Gm-Message-State: AOJu0YyJ0P2/w4KOyV8vvNJAUr1aUl4WMawut34Me+iy92cZILFny6WG pC7gqBsiecBgjuQLQ2QwwwUiEJezax1Uo0uMy4gn4EQGTjn3ZQhcDycD X-Gm-Gg: ATEYQzzAElJwwhDVaj9IP1Wq1hK6vnQ/vjbL0+irQWojo4JUuoVEAH5I7hnPHh/w2OY XYn4J1V++ZRSrFakDNkyLpFfzpmTej8G90bji6MeAO3M88G3uJtw+KHqNRcglkMffqXXifV50t9 VehBa3YQ8ymzs/ykB4c4VP3r2v15mTwOzE9oH+PsHYq7jXPm5LkEOCiBq4sI6djFQJfrcFYLqxP Z/t5LSIhH5Gd3C36MM7UEafLpcWi93z3BxRuNRN/zW9xUzydY/15ZzC4u8mUVhXTq2klfpDGyl0 NOMvoRm4PUqj/37pV9o+OgH8ER0fyRApadIdeZ761cIgudBV7/UlXl+ATySdIkU4DoGgPS0BAnw YqSn/CP28L21AC5SxQ8BMPVjXKBZAl7kZEnpVe+/kgVd6/nL7s4EE/IVy60VAsbg1psB5WTNpMD cloVwG1UN6wh/24xNrh+x6rPcq3BFydpUG65JXqaO+GjZQ X-Received: by 2002:a05:6402:528f:b0:66c:12ad:d769 with SMTP id 4fb4d7f45d1cf-66c12add9fbmr216280a12.7.1774864360007; Mon, 30 Mar 2026 02:52:40 -0700 (PDT) Received: from [192.168.178.84] ([134.19.50.110]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-66b75ba970esm2306523a12.19.2026.03.30.02.52.39 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 30 Mar 2026 02:52:39 -0700 (PDT) Message-ID: <45754304-12c4-44b2-965c-fee97f839808@gmail.com> Date: Mon, 30 Mar 2026 11:52:38 +0200 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] dma-fence: Dereference correct dma_fence in dma_fence_chain_find_seqno() To: Li Ming , Sumit Semwal , Lionel Landwerlin Cc: =?UTF-8?Q?Christian_K=C3=B6nig?= , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org References: <20260327-fix_dma_fence_chain_find_seqno-v1-1-60e80bfb43c8@zohomail.com> Content-Language: en-US From: =?UTF-8?Q?Christian_K=C3=B6nig?= In-Reply-To: <20260327-fix_dma_fence_chain_find_seqno-v1-1-60e80bfb43c8@zohomail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/27/26 15:33, Li Ming wrote: > dma_fence_chain_find_seqno() uses dma_fence_chain_for_each() to walk a > given dma_fence_chain. dma_fence_chain_for_each() always holds a > reference for the current fence during iteration. The reference must > be dropped after breaking out. Instead of dereferencing the last fence > as intended, dma_fence_chain_find_seqno() incorrectly dereferences the > first fence in the chain. Well once more: Absolutely clear NAK and please search the mailing list for similar changes before you send a patch out. The existing code is perfectly correct and I can't count how often I had to reject that patch. I think the functionality is obvious but it looks like we really need to add a comment here. Regards, Christian. > > Fixes: 7bf60c52e093 ("dma-buf: add new dma_fence_chain container v7") > Signed-off-by: Li Ming > --- > drivers/dma-buf/dma-fence-chain.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dma-buf/dma-fence-chain.c b/drivers/dma-buf/dma-fence-chain.c > index a8a90acf4f34..71fa173aef13 100644 > --- a/drivers/dma-buf/dma-fence-chain.c > +++ b/drivers/dma-buf/dma-fence-chain.c > @@ -103,7 +103,7 @@ int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t seqno) > to_dma_fence_chain(*pfence)->prev_seqno < seqno) > break; > } > - dma_fence_put(&chain->base); > + dma_fence_put(*pfence); > > return 0; > } > > --- > base-commit: c369299895a591d96745d6492d4888259b004a9e > change-id: 20260327-fix_dma_fence_chain_find_seqno-7adea64efe01 > > Best regards, > -- > Li Ming >