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[86.9.19.6]) by smtp.gmail.com with ESMTPSA id s13sm13453572wmc.28.2019.10.21.05.32.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Oct 2019 05:32:37 -0700 (PDT) Date: Mon, 21 Oct 2019 13:32:35 +0100 From: Daniel Thompson To: Lee Jones Subject: Re: [PATCH v2 7/9] mfd: mfd-core: Protect against NULL call-back function pointer Message-ID: <20191021123235.royyfp4mxrvsgioh@holly.lan> References: <20191021105822.20271-1-lee.jones@linaro.org> <20191021105822.20271-8-lee.jones@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191021105822.20271-8-lee.jones@linaro.org> User-Agent: NeoMutt/20180716 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191021_053239_139280_5C7077DA X-CRM114-Status: GOOD ( 16.06 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: baohua@kernel.org, stephan@gerhold.net, arnd@arndb.de, linus.walleij@linaro.org, linux-kernel@vger.kernel.org, broonie@kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 21, 2019 at 11:58:20AM +0100, Lee Jones wrote: > If a child device calls mfd_cell_{en,dis}able() without an appropriate > call-back being set, we are likely to encounter a panic. Avoid this > by adding suitable checking. > > Signed-off-by: Lee Jones > --- > drivers/mfd/mfd-core.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c > index 8126665bb2d8..90b43b44a15a 100644 > --- a/drivers/mfd/mfd-core.c > +++ b/drivers/mfd/mfd-core.c > @@ -28,6 +28,11 @@ int mfd_cell_enable(struct platform_device *pdev) > const struct mfd_cell *cell = mfd_get_cell(pdev); > int err = 0; > > + if (!cell->enable) { > + dev_dbg(&pdev->dev, "No .enable() call-back registered\n"); > + return 0; > + } > + > /* only call enable hook if the cell wasn't previously enabled */ > if (atomic_inc_return(cell->usage_count) == 1) > err = cell->enable(pdev); > @@ -45,6 +50,11 @@ int mfd_cell_disable(struct platform_device *pdev) > const struct mfd_cell *cell = mfd_get_cell(pdev); > int err = 0; > > + if (!cell->enable) { Oops. Cancel the R-B: ;-). Shouldn't this be !cell->disable() ? Daniel. > + dev_dbg(&pdev->dev, "No .disable() call-back registered\n"); > + return 0; > + } > + > /* only disable if no other clients are using it */ > if (atomic_dec_return(cell->usage_count) == 0) > err = cell->disable(pdev); > -- > 2.17.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel