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[73.225.163.254]) by smtp.gmail.com with ESMTPSA id l191sm1231705pfc.91.2016.07.19.22.34.01 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 19 Jul 2016 22:34:01 -0700 (PDT) From: Andrey Smirnov To: linux-mtd@lists.infradead.org Subject: [PATCH v2 1/2] mtd: nand: Error out if cmd_ctrl() is missing Date: Tue, 19 Jul 2016 22:33:57 -0700 Message-Id: <1468992838-23474-1-git-send-email-andrew.smirnov@gmail.com> X-Mailer: git-send-email 2.5.5 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160719_223423_624550_7AADBA9E X-CRM114-Status: GOOD ( 18.05 ) X-Spam-Score: -2.7 (--) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-2.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [2607:f8b0:400e:c03:0:0:0:243 listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (andrew.smirnov[at]gmail.com) -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Boris Brezillon , Andrey Smirnov , Richard Weinberger , linux-kernel@vger.kernel.org, Brian Norris , David Woodhouse MIME-Version: 1.0 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org If no user specified chip->select_chip() function is provided, code in nand_base.c will automatically set this hook to nand_select_chip(), which in turn depends on chip->cmd_ctrl() hook being valid. Not providing both of those functions in NAND controller driver (for example by mistake) will result in a bit cryptic segfault. Same is true for chip->cmdfunc(). To avoid the above scenario change the prototype of nand_set_defaults() to return error code, all the callers to check for it and error out if cmd_ctrl() is not provided. Suggested-by: Brian Norris Signed-off-by: Andrey Smirnov --- drivers/mtd/nand/nand_base.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index ce7b2ca..bee480f 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -3114,22 +3114,30 @@ static void nand_shutdown(struct mtd_info *mtd) } /* Set default functions */ -static void nand_set_defaults(struct nand_chip *chip, int busw) +static int nand_set_defaults(struct nand_chip *chip, int busw) { /* check for proper chip_delay setup, set 20us if not */ if (!chip->chip_delay) chip->chip_delay = 20; /* check, if a user supplied command function given */ - if (chip->cmdfunc == NULL) + if (chip->cmdfunc == NULL) { + if (!chip->cmd_ctrl) + goto no_cmd_ctrl; + chip->cmdfunc = nand_command; + } /* check, if a user supplied wait function given */ if (chip->waitfunc == NULL) chip->waitfunc = nand_wait; - if (!chip->select_chip) + if (!chip->select_chip) { + if (!chip->cmd_ctrl) + goto no_cmd_ctrl; + chip->select_chip = nand_select_chip; + } /* set for ONFI nand */ if (!chip->onfi_set_features) @@ -3161,6 +3169,11 @@ static void nand_set_defaults(struct nand_chip *chip, int busw) init_waitqueue_head(&chip->controller->wq); } + return 0; + +no_cmd_ctrl: + pr_err("chip.cmd_ctrl() callback is not provided\n"); + return -EINVAL; } /* Sanitize ONFI strings so we can safely print them */ @@ -3878,9 +3891,13 @@ ident_done: } if (chip->options & NAND_BUSWIDTH_AUTO) { + int ret; + WARN_ON(chip->options & NAND_BUSWIDTH_16); chip->options |= busw; - nand_set_defaults(chip, busw); + ret = nand_set_defaults(chip, busw); + if (ret < 0) + return ERR_PTR(ret); } else if (busw != (chip->options & NAND_BUSWIDTH_16)) { /* * Check, if buswidth is correct. Hardware drivers should set @@ -3998,7 +4015,9 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips, mtd->name = dev_name(mtd->dev.parent); /* Set the default functions */ - nand_set_defaults(chip, chip->options & NAND_BUSWIDTH_16); + ret = nand_set_defaults(chip, chip->options & NAND_BUSWIDTH_16); + if (ret < 0) + return ret; /* Read the flash type */ type = nand_get_flash_type(mtd, chip, &nand_maf_id,