From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH 3/3] i2c: i801: avoid panic if ioreamp fails Date: Fri, 10 May 2019 10:09:55 +0200 Message-ID: <20190510100955.497a1a57@endymion> References: <20190510030320.109154-1-wangkefeng.wang@huawei.com> <20190510030320.109154-3-wangkefeng.wang@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190510030320.109154-3-wangkefeng.wang@huawei.com> Sender: linux-kernel-owner@vger.kernel.org To: Kefeng Wang Cc: linux-kernel@vger.kernel.org, Wolfram Sang , linux-i2c@vger.kernel.org, Hulk Robot List-Id: linux-i2c@vger.kernel.org Hi Kefeng, On Fri, 10 May 2019 11:03:20 +0800, Kefeng Wang wrote: > If ioremap fails, NULL pointer dereference will happen and > leading to a kernel panic when access the virtual address > in check_signature(). > > Fix it by check the return value of ioremap. > > Cc: Jean Delvare > Cc: Wolfram Sang > Cc: linux-i2c@vger.kernel.org > Reported-by: Hulk Robot > Signed-off-by: Kefeng Wang > --- > drivers/i2c/busses/i2c-i801.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c > index 679c6c41f64b..fc6ccb8aba17 100644 > --- a/drivers/i2c/busses/i2c-i801.c > +++ b/drivers/i2c/busses/i2c-i801.c > @@ -1068,7 +1068,10 @@ static void __init input_apanel_init(void) > void __iomem *bios; > const void __iomem *p; > > - bios = ioremap(0xF0000, 0x10000); /* Can't fail */ > + bios = ioremap(0xF0000, 0x10000); > + if (!base) That would be "if (!bios)". Please don't send patches without at least test-building the result. We don't need this anyway. The comment says it can't fail, so why bother checking for a condition which will never happen? > + return -ENOMEM; > + > p = bios_signature(bios); > if (p) { > /* just use the first address */ -- Jean Delvare SUSE L3 Support