https://github.com/torvalds/linux
Revision f275a4659484716259cc46268d9043424e51cf0f authored by Paul Kocialkowski on 27 December 2018, 15:42:25 UTC, committed by Wolfram Sang on 15 February 2019, 08:45:05 UTC
The driver's interrupt handler checks whether a message is currently
being handled with the curr_msg pointer. When it is NULL, the interrupt
is considered to be unexpected. Similarly, the i2c_start_transfer
routine checks for the remaining number of messages to handle in
num_msgs.

However, these values are never cleared and always keep the message and
number relevant to the latest transfer (which might be done already and
the underlying message memory might have been freed).

When an unexpected interrupt hits with the DONE bit set, the isr will
then try to access the flags field of the curr_msg structure, leading
to a fatal page fault.

The msg_buf and msg_buf_remaining fields are also never cleared at the
end of the transfer, which can lead to similar pitfalls.

Fix these issues by introducing a cleanup function and always calling
it after a transfer is finished.

Fixes: e2474541032d ("i2c: bcm2835: Fix hang for writing messages larger than 16 bytes")
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
1 parent d358def
Raw File
Tip revision: f275a4659484716259cc46268d9043424e51cf0f authored by Paul Kocialkowski on 27 December 2018, 15:42:25 UTC
i2c: bcm2835: Clear current buffer pointers and counts after a transfer
Tip revision: f275a46
do_mounts_md.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/delay.h>
#include <linux/raid/md_u.h>
#include <linux/raid/md_p.h>

#include "do_mounts.h"

/*
 * When md (and any require personalities) are compiled into the kernel
 * (not a module), arrays can be assembles are boot time using with AUTODETECT
 * where specially marked partitions are registered with md_autodetect_dev(),
 * and with MD_BOOT where devices to be collected are given on the boot line
 * with md=.....
 * The code for that is here.
 */

#ifdef CONFIG_MD_AUTODETECT
static int __initdata raid_noautodetect;
#else
static int __initdata raid_noautodetect=1;
#endif
static int __initdata raid_autopart;

static struct {
	int minor;
	int partitioned;
	int level;
	int chunk;
	char *device_names;
} md_setup_args[256] __initdata;

static int md_setup_ents __initdata;

/*
 * Parse the command-line parameters given our kernel, but do not
 * actually try to invoke the MD device now; that is handled by
 * md_setup_drive after the low-level disk drivers have initialised.
 *
 * 27/11/1999: Fixed to work correctly with the 2.3 kernel (which
 *             assigns the task of parsing integer arguments to the
 *             invoked program now).  Added ability to initialise all
 *             the MD devices (by specifying multiple "md=" lines)
 *             instead of just one.  -- KTK
 * 18May2000: Added support for persistent-superblock arrays:
 *             md=n,0,factor,fault,device-list   uses RAID0 for device n
 *             md=n,-1,factor,fault,device-list  uses LINEAR for device n
 *             md=n,device-list      reads a RAID superblock from the devices
 *             elements in device-list are read by name_to_kdev_t so can be
 *             a hex number or something like /dev/hda1 /dev/sdb
 * 2001-06-03: Dave Cinege <dcinege@psychosis.com>
 *		Shifted name_to_kdev_t() and related operations to md_set_drive()
 *		for later execution. Rewrote section to make devfs compatible.
 */
static int __init md_setup(char *str)
{
	int minor, level, factor, fault, partitioned = 0;
	char *pername = "";
	char *str1;
	int ent;

	if (*str == 'd') {
		partitioned = 1;
		str++;
	}
	if (get_option(&str, &minor) != 2) {	/* MD Number */
		printk(KERN_WARNING "md: Too few arguments supplied to md=.\n");
		return 0;
	}
	str1 = str;
	for (ent=0 ; ent< md_setup_ents ; ent++)
		if (md_setup_args[ent].minor == minor &&
		    md_setup_args[ent].partitioned == partitioned) {
			printk(KERN_WARNING "md: md=%s%d, Specified more than once. "
			       "Replacing previous definition.\n", partitioned?"d":"", minor);
			break;
		}
	if (ent >= ARRAY_SIZE(md_setup_args)) {
		printk(KERN_WARNING "md: md=%s%d - too many md initialisations\n", partitioned?"d":"", minor);
		return 0;
	}
	if (ent >= md_setup_ents)
		md_setup_ents++;
	switch (get_option(&str, &level)) {	/* RAID level */
	case 2: /* could be 0 or -1.. */
		if (level == 0 || level == LEVEL_LINEAR) {
			if (get_option(&str, &factor) != 2 ||	/* Chunk Size */
					get_option(&str, &fault) != 2) {
				printk(KERN_WARNING "md: Too few arguments supplied to md=.\n");
				return 0;
			}
			md_setup_args[ent].level = level;
			md_setup_args[ent].chunk = 1 << (factor+12);
			if (level ==  LEVEL_LINEAR)
				pername = "linear";
			else
				pername = "raid0";
			break;
		}
		/* FALL THROUGH */
	case 1: /* the first device is numeric */
		str = str1;
		/* FALL THROUGH */
	case 0:
		md_setup_args[ent].level = LEVEL_NONE;
		pername="super-block";
	}

	printk(KERN_INFO "md: Will configure md%d (%s) from %s, below.\n",
		minor, pername, str);
	md_setup_args[ent].device_names = str;
	md_setup_args[ent].partitioned = partitioned;
	md_setup_args[ent].minor = minor;

	return 1;
}

static void __init md_setup_drive(void)
{
	int minor, i, ent, partitioned;
	dev_t dev;
	dev_t devices[MD_SB_DISKS+1];

	for (ent = 0; ent < md_setup_ents ; ent++) {
		int fd;
		int err = 0;
		char *devname;
		mdu_disk_info_t dinfo;
		char name[16];

		minor = md_setup_args[ent].minor;
		partitioned = md_setup_args[ent].partitioned;
		devname = md_setup_args[ent].device_names;

		sprintf(name, "/dev/md%s%d", partitioned?"_d":"", minor);
		if (partitioned)
			dev = MKDEV(mdp_major, minor << MdpMinorShift);
		else
			dev = MKDEV(MD_MAJOR, minor);
		create_dev(name, dev);
		for (i = 0; i < MD_SB_DISKS && devname != NULL; i++) {
			char *p;
			char comp_name[64];
			u32 rdev;

			p = strchr(devname, ',');
			if (p)
				*p++ = 0;

			dev = name_to_dev_t(devname);
			if (strncmp(devname, "/dev/", 5) == 0)
				devname += 5;
			snprintf(comp_name, 63, "/dev/%s", devname);
			rdev = bstat(comp_name);
			if (rdev)
				dev = new_decode_dev(rdev);
			if (!dev) {
				printk(KERN_WARNING "md: Unknown device name: %s\n", devname);
				break;
			}

			devices[i] = dev;

			devname = p;
		}
		devices[i] = 0;

		if (!i)
			continue;

		printk(KERN_INFO "md: Loading md%s%d: %s\n",
			partitioned ? "_d" : "", minor,
			md_setup_args[ent].device_names);

		fd = ksys_open(name, 0, 0);
		if (fd < 0) {
			printk(KERN_ERR "md: open failed - cannot start "
					"array %s\n", name);
			continue;
		}
		if (ksys_ioctl(fd, SET_ARRAY_INFO, 0) == -EBUSY) {
			printk(KERN_WARNING
			       "md: Ignoring md=%d, already autodetected. (Use raid=noautodetect)\n",
			       minor);
			ksys_close(fd);
			continue;
		}

		if (md_setup_args[ent].level != LEVEL_NONE) {
			/* non-persistent */
			mdu_array_info_t ainfo;
			ainfo.level = md_setup_args[ent].level;
			ainfo.size = 0;
			ainfo.nr_disks =0;
			ainfo.raid_disks =0;
			while (devices[ainfo.raid_disks])
				ainfo.raid_disks++;
			ainfo.md_minor =minor;
			ainfo.not_persistent = 1;

			ainfo.state = (1 << MD_SB_CLEAN);
			ainfo.layout = 0;
			ainfo.chunk_size = md_setup_args[ent].chunk;
			err = ksys_ioctl(fd, SET_ARRAY_INFO, (long)&ainfo);
			for (i = 0; !err && i <= MD_SB_DISKS; i++) {
				dev = devices[i];
				if (!dev)
					break;
				dinfo.number = i;
				dinfo.raid_disk = i;
				dinfo.state = (1<<MD_DISK_ACTIVE)|(1<<MD_DISK_SYNC);
				dinfo.major = MAJOR(dev);
				dinfo.minor = MINOR(dev);
				err = ksys_ioctl(fd, ADD_NEW_DISK,
						 (long)&dinfo);
			}
		} else {
			/* persistent */
			for (i = 0; i <= MD_SB_DISKS; i++) {
				dev = devices[i];
				if (!dev)
					break;
				dinfo.major = MAJOR(dev);
				dinfo.minor = MINOR(dev);
				ksys_ioctl(fd, ADD_NEW_DISK, (long)&dinfo);
			}
		}
		if (!err)
			err = ksys_ioctl(fd, RUN_ARRAY, 0);
		if (err)
			printk(KERN_WARNING "md: starting md%d failed\n", minor);
		else {
			/* reread the partition table.
			 * I (neilb) and not sure why this is needed, but I cannot
			 * boot a kernel with devfs compiled in from partitioned md
			 * array without it
			 */
			ksys_close(fd);
			fd = ksys_open(name, 0, 0);
			ksys_ioctl(fd, BLKRRPART, 0);
		}
		ksys_close(fd);
	}
}

static int __init raid_setup(char *str)
{
	int len, pos;

	len = strlen(str) + 1;
	pos = 0;

	while (pos < len) {
		char *comma = strchr(str+pos, ',');
		int wlen;
		if (comma)
			wlen = (comma-str)-pos;
		else	wlen = (len-1)-pos;

		if (!strncmp(str, "noautodetect", wlen))
			raid_noautodetect = 1;
		if (!strncmp(str, "autodetect", wlen))
			raid_noautodetect = 0;
		if (strncmp(str, "partitionable", wlen)==0)
			raid_autopart = 1;
		if (strncmp(str, "part", wlen)==0)
			raid_autopart = 1;
		pos += wlen+1;
	}
	return 1;
}

__setup("raid=", raid_setup);
__setup("md=", md_setup);

static void __init autodetect_raid(void)
{
	int fd;

	/*
	 * Since we don't want to detect and use half a raid array, we need to
	 * wait for the known devices to complete their probing
	 */
	printk(KERN_INFO "md: Waiting for all devices to be available before autodetect\n");
	printk(KERN_INFO "md: If you don't use raid, use raid=noautodetect\n");

	wait_for_device_probe();

	fd = ksys_open("/dev/md0", 0, 0);
	if (fd >= 0) {
		ksys_ioctl(fd, RAID_AUTORUN, raid_autopart);
		ksys_close(fd);
	}
}

void __init md_run_setup(void)
{
	create_dev("/dev/md0", MKDEV(MD_MAJOR, 0));

	if (raid_noautodetect)
		printk(KERN_INFO "md: Skipping autodetection of RAID arrays. (raid=autodetect will force)\n");
	else
		autodetect_raid();
	md_setup_drive();
}
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