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Commit e4258d55 authored by Stefan Weinhuber's avatar Stefan Weinhuber Committed by Heiko Carstens
Browse files

[S390] dasd: use vmalloc for statistics input buffer 



The size of the buffer that is used to store DASD statistics input
strings depends on the user input. If the input string is to large,
the write operation could fail with -ENOMEM. To avoid this, use
vmalloc instead of kmalloc.

Signed-off-by: default avatarStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
parent 7dd6b334

drivers/s390/block/dasd.c

+5 −4
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/mutex.h>

#include <linux/debugfs.h>

#include <linux/seq_file.h>

#include <linux/vmalloc.h>



#include <asm/ccwdev.h>

#include <asm/ebcdic.h>
@@ -888,11 +889,11 @@ char *dasd_get_user_string(const char __user *user_buf, size_t user_len) 
{

	char *buffer;



	buffer = kmalloc(user_len + 1, GFP_KERNEL);

	buffer = vmalloc(user_len + 1);

	if (buffer == NULL)

		return ERR_PTR(-ENOMEM);

	if (copy_from_user(buffer, user_buf, user_len) != 0) {

		kfree(buffer);

		vfree(buffer);

		return ERR_PTR(-EFAULT);

	}

	/* got the string, now strip linefeed. */
@@ -930,7 +931,7 @@ static ssize_t dasd_stats_write(struct file *file, 
		dasd_profile_off(prof);

	} else

		rc = -EINVAL;

	kfree(buffer);

	vfree(buffer);

	return rc;

}
@@ -1042,7 +1043,7 @@ static ssize_t dasd_stats_global_write(struct file *file, 
		dasd_global_profile_level = DASD_PROFILE_OFF;

	} else

		rc = -EINVAL;

	kfree(buffer);

	vfree(buffer);

	return rc;

}

drivers/s390/block/dasd_proc.c

+2 −2
Original line number Diff line number Diff line
@@ -312,14 +312,14 @@ static ssize_t dasd_stats_proc_write(struct file *file, 
		pr_info("The statistics have been reset\n");

	} else

		goto out_parse_error;

	kfree(buffer);

	vfree(buffer);

	return user_len;

out_parse_error:

	rc = -EINVAL;

	pr_warning("%s is not a supported value for /proc/dasd/statistics\n",

		str);

out_error:

	kfree(buffer);

	vfree(buffer);

	return rc;

#else

	pr_warning("/proc/dasd/statistics: is not activated in this kernel\n");