From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julia Lawall Subject: Re: [patch 2/2] ACPI / debugger: copy_to_user doesn't return errors Date: Thu, 24 Dec 2015 08:39:06 +0100 (CET) Message-ID: References: <20151224072437.GB29642@mwanda> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <20151224072437.GB29642@mwanda> Sender: kernel-janitors-owner@vger.kernel.org To: Dan Carpenter Cc: "Rafael J. Wysocki" , Lv Zheng , Len Brown , linux-acpi@vger.kernel.org, kernel-janitors@vger.kernel.org List-Id: linux-acpi@vger.kernel.org On Thu, 24 Dec 2015, Dan Carpenter wrote: > The copy_to/from_user() functions don't return error codes, they return > the number of bytes remaining. We had intended to return -EFUALT here. > We actually have already checked access_ok() in an earlier function so > I don't think these functions will fail but let's fix it anyway. > > Signed-off-by: Dan Carpenter > > diff --git a/drivers/acpi/acpi_dbg.c b/drivers/acpi/acpi_dbg.c > index f2c92ab..2a1777b 100644 > --- a/drivers/acpi/acpi_dbg.c > +++ b/drivers/acpi/acpi_dbg.c > @@ -592,9 +592,10 @@ static int acpi_aml_read_user(char __user *buf, int len) > smp_rmb(); > p = &crc->buf[crc->tail]; > n = min(len, circ_count_to_end(crc)); > - ret = copy_to_user(buf, p, n); > - if (IS_ERR_VALUE(ret)) I'm not familiar with IS_ERR_VALUE. Is it to allow functions that return unsigned values to also return negative error codes? thanks, julia > + if (copy_to_user(buf, p, n)) { > + ret = -EFAULT; > goto out; > + } > /* sync tail after removing logs */ > smp_mb(); > crc->tail = (crc->tail + n) & (ACPI_AML_BUF_SIZE - 1); > @@ -661,9 +662,10 @@ static int acpi_aml_write_user(const char __user *buf, int len) > smp_mb(); > p = &crc->buf[crc->head]; > n = min(len, circ_space_to_end(crc)); > - ret = copy_from_user(p, buf, n); > - if (IS_ERR_VALUE(ret)) > + if (copy_from_user(p, buf, n)) { > + ret = -EFAULT; > goto out; > + } > /* sync head after inserting cmds */ > smp_wmb(); > crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1); > -- > To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >