From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kefeng Wang Subject: Re: [PATCH 3/3] i2c: i801: avoid panic if ioreamp fails Date: Fri, 10 May 2019 17:35:46 +0800 Message-ID: <164bb498-35dc-b226-4adb-3d743f4790a1@huawei.com> References: <20190510030320.109154-1-wangkefeng.wang@huawei.com> <20190510030320.109154-3-wangkefeng.wang@huawei.com> <20190510100955.497a1a57@endymion> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190510100955.497a1a57@endymion> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jean Delvare Cc: linux-kernel@vger.kernel.org, Wolfram Sang , linux-i2c@vger.kernel.org, Hulk Robot List-Id: linux-i2c@vger.kernel.org On 2019/5/10 16:09, Jean Delvare wrote: > 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. sorry,  copy error. > We don't need this anyway. The comment says it can't fail, so why > bother checking for a condition which will never happen? The ioremap could fails due to no memory, our inner test robot(enable FAULT_INJECTION) find this issue. > >> + return -ENOMEM; >> + >> p = bios_signature(bios); >> if (p) { >> /* just use the first address */ >