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smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AyzBC3dy; 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="AyzBC3dy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 499CCC4CEE2; Tue, 21 Jan 2025 20:23:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737490992; bh=nuaalhW0jpPUOyqKzjbiV4YkyqBzIjJbLc5NvbsiwWc=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=AyzBC3dyXM3Np6BAGQI7fIrw8wUOZ/BhxwMHqH6v8E52kAmVcyWvAfMqaD8/E9h4W UK+UFis+djkpHWL/doK889Cx3OjCy31NYdt38AvPgJM9Y/y4yvFeMkXt46cwRLXJ4T kLUTN8r1NcSaVG/oudSN+EXtCAO14gkxCN8+dW0C2exbKCcmg/7B2PiAyvf57nQU+K DSV1wneIzT2qfa9dNLydhheXFVv5bP/hpr+txSaN4zhOaAIdGIjAMcJ1SOt0NGYVQ3 RtCr/73lCyD+KIfX4O9BhIOTkP6e69IVNoXXL4C5CrqGMUjZxACO6KtgJT0qEme9L2 i/9PMTimbp/kA== Date: Tue, 21 Jan 2025 14:23:10 -0600 From: Bjorn Helgaas To: Hans Zhang <18255117159@163.com>, Jon Hunter Cc: manivannan.sadhasivam@linaro.org, kw@linux.com, kishon@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, rockswang7@gmail.com, Niklas Cassel , linux-tegra@vger.kernel.org Subject: Re: [v11 2/2] misc: pci_endpoint_test: Fix overflow of bar_size Message-ID: <20250121202310.GA979442@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <7474af29-2995-48f6-830b-a23dad2d2bd1@nvidia.com> On Tue, Jan 21, 2025 at 05:46:43PM +0000, Jon Hunter wrote: > On 09/01/2025 09:45, Hans Zhang wrote: > > With 8GB BAR2, running pcitest -b 2 fails with "TEST FAILED". > > > > The return value of the `pci_resource_len` interface is not an integer. > > Using `pcitest` with an 8GB BAR2, the bar_size of integer type will > > overflow. > > > > Change the data type of bar_size from integer to resource_size_t, to fix > > the above issue. > > > > Signed-off-by: Hans Zhang <18255117159@163.com> > > Suggested-by: Niklas Cassel > > Reviewed-by: Niklas Cassel > > --- > > Changes since v10: > > https://lore.kernel.org/linux-pci/20250108080951.1700230-3-18255117159@163.com/ > > > > - Replace do_div with the div_u64 API. > > > > Changes since v8-v9: > > https://lore.kernel.org/linux-pci/20250104151652.1652181-1-18255117159@163.com/ > > > > - Split the patch. > > > > Changes since v4-v7: > > https://lore.kernel.org/linux-pci/20250102120222.1403906-1-18255117159@163.com/ > > > > - Fix 32-bit OS warnings and errors. > > - Fix undefined reference to `__udivmoddi4` > > > > Changes since v3: > > https://lore.kernel.org/linux-pci/20241221141009.27317-1-18255117159@163.com/ > > > > - The patch subject were modified. > > > > Changes since v2: > > https://lore.kernel.org/linux-pci/20241220075253.16791-1-18255117159@163.com/ > > > > - Fix "changes" part goes below the --- line > > - The patch commit message were modified. > > > > Changes since v1: > > https://lore.kernel.org/linux-pci/20241217121220.19676-1-18255117159@163.com/ > > > > - The patch subject and commit message were modified. > > --- > > drivers/misc/pci_endpoint_test.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c > > index f78c7540c52c..0f6291801078 100644 > > --- a/drivers/misc/pci_endpoint_test.c > > +++ b/drivers/misc/pci_endpoint_test.c > > @@ -280,10 +280,11 @@ static int pci_endpoint_test_bar_memcmp(struct pci_endpoint_test *test, > > static bool pci_endpoint_test_bar(struct pci_endpoint_test *test, > > enum pci_barno barno) > > { > > - int j, bar_size, buf_size, iters; > > + int j, buf_size, iters; > > void *write_buf __free(kfree) = NULL; > > void *read_buf __free(kfree) = NULL; > > struct pci_dev *pdev = test->pdev; > > + resource_size_t bar_size; > > if (!test->bar[barno]) > > return false; > > @@ -307,7 +308,7 @@ static bool pci_endpoint_test_bar(struct pci_endpoint_test *test, > > if (!read_buf) > > return false; > > - iters = bar_size / buf_size; > > + iters = div_u64(bar_size, buf_size); > > for (j = 0; j < iters; j++) > > if (pci_endpoint_test_bar_memcmp(test, barno, buf_size * j, > > write_buf, read_buf, buf_size)) > > > This change breaks building the kernel with GCC v7 and I see ... > > ERROR: modpost: "__aeabi_uldivmod" [drivers/misc/pci_endpoint_test.ko] > undefined! > ERROR: modpost: "__aeabi_ldivmod" [drivers/misc/pci_endpoint_test.ko] > undefined! > > I know that this is an old GCC version, but this is a farm builder and the > kernel still indicates that GCC v5.1 is still supported [0]. > > Jon > > [0] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/Documentation/process/changes.rst Dropping from pci/endpoint-test for now until this gets sorted out. For reference, the current iteration (the one I'm dropping) is below: commit c6e73776c0c4 ("misc: pci_endpoint_test: Prevent bar_size overflow") Author: Hans Zhang <18255117159@163.com> Date: Thu Jan 9 17:45:56 2025 +0800 misc: pci_endpoint_test: Prevent bar_size overflow Running 'pcitest -b 2' fails with "TEST FAILED" when the BAR2 size exceeds 4GB. The return value of the pci_resource_len() macro can be larger than that of a signed integer type. As such, for example, when using 'pcitest' with an 8GB BAR2, the bar_size of the integer type will overflow. Change bar_size from integer to resource_size_t to prevent integer overflow for large BAR sizes with 32-bit compilers. Similarly, use div_u64() to perform 64-bit division in that situation. Link: https://lore.kernel.org/r/20250109094556.1724663-3-18255117159@163.com Signed-off-by: Hans Zhang <18255117159@163.com> [kwilczynski: commit log] Signed-off-by: Krzysztof Wilczyński [bhelgaas: pick up commit log update from https://lore.kernel.org/r/Z4jTEkznMUcApzbe@ryzen] Signed-off-by: Bjorn Helgaas Reviewed-by: Niklas Cassel Reviewed-by: Manivannan Sadhasivam diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c index be0c7c870e6a..abe6c8f03fca 100644 --- a/drivers/misc/pci_endpoint_test.c +++ b/drivers/misc/pci_endpoint_test.c @@ -283,10 +283,11 @@ static int pci_endpoint_test_bar_memcmp(struct pci_endpoint_test *test, static bool pci_endpoint_test_bar(struct pci_endpoint_test *test, enum pci_barno barno) { - int j, bar_size, buf_size, iters; + int j, buf_size, iters; void *write_buf __free(kfree) = NULL; void *read_buf __free(kfree) = NULL; struct pci_dev *pdev = test->pdev; + resource_size_t bar_size; if (!test->bar[barno]) return false; @@ -310,7 +311,7 @@ static bool pci_endpoint_test_bar(struct pci_endpoint_test *test, if (!read_buf) return false; - iters = bar_size / buf_size; + iters = div_u64(bar_size, buf_size); for (j = 0; j < iters; j++) if (pci_endpoint_test_bar_memcmp(test, barno, buf_size * j, write_buf, read_buf, buf_size))