/*
 * Many of the syscalls used in this file expect some of the arguments
 * to be __user pointers not __kernel pointers.  To limit the sparse
 * noise, turn off sparse checking for this file.
 */
#ifdef __CHECKER__
#undef __CHECKER__
#warning "Sparse checking disabled for this file"
#endif

#include <linux/unistd.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/minix_fs.h>
#include <linux/romfs_fs.h>
#include <linux/initrd.h>
#include <linux/sched.h>
#include <linux/freezer.h>
#include <linux/kmod.h>

#include "do_mounts.h"

unsigned long initrd_start, initrd_end;
int initrd_below_start_ok;
unsigned int real_root_dev;	/* do_proc_dointvec cannot handle kdev_t */
static int __initdata mount_initrd = 1;

static int __init no_initrd(char *str)
{
	mount_initrd = 0;
	return 1;
}

__setup("noinitrd", no_initrd);

static int init_linuxrc(struct subprocess_info *info, struct cred *new)
{
	sys_unshare(CLONE_FS | CLONE_FILES);
	/* stdin/stdout/stderr for /linuxrc */
	sys_open("/dev/console", O_RDWR, 0);
	sys_dup(0);
	sys_dup(0);
	/* move initrd over / and chdir/chroot in initrd root */
	sys_chdir("/root");
	sys_mount(".", "/", NULL, MS_MOVE, NULL);
	sys_chroot(".");
	sys_setsid();
	return 0;
}

static void __init handle_initrd(void)
{
	struct subprocess_info *info;
	static char *argv[] = { "linuxrc", NULL, };
	extern char *envp_init[];
	int error;

	real_root_dev = new_encode_dev(ROOT_DEV);
	create_dev("/dev/root.old", Root_RAM0);
	/* mount initrd on rootfs' /root */
	mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
	sys_mkdir("/old", 0700);
	sys_chdir("/old");

	/* try loading default modules from initrd */
	load_default_modules();

	/*
	 * In case that a resume from disk is carried out by linuxrc or one of
	 * its children, we need to tell the freezer not to wait for us.
	 */
	current->flags |= PF_FREEZER_SKIP;

	info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
					 GFP_KERNEL, init_linuxrc, NULL, NULL);
	if (!info)
		return;
	call_usermodehelper_exec(info, UMH_WAIT_PROC);

	current->flags &= ~PF_FREEZER_SKIP;

	/* move initrd to rootfs' /old */
	sys_mount("..", ".", NULL, MS_MOVE, NULL);
	/* switch root and cwd back to / of rootfs */
	sys_chroot("..");

	if (new_decode_dev(real_root_dev) == Root_RAM0) {
		sys_chdir("/old");
		return;
	}

	sys_chdir("/");
	ROOT_DEV = new_decode_dev(real_root_dev);
	mount_root();

	printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
	error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
	if (!error)
		printk("okay\n");
	else {
		int fd = sys_open("/dev/root.old", O_RDWR, 0);
		if (error == -ENOENT)
			printk("/initrd does not exist. Ignored.\n");
		else
			printk("failed\n");
		printk(KERN_NOTICE "Unmounting old root\n");
		sys_umount("/old", MNT_DETACH);
		printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
		if (fd < 0) {
			error = fd;
		} else {
			error = sys_ioctl(fd, BLKFLSBUF, 0);
			sys_close(fd);
		}
		printk(!error ? "okay\n" : "failed\n");
	}
}

bool __init initrd_load(void)
{
	if (mount_initrd) {
		create_dev("/dev/ram", Root_RAM0);
		/*
		 * Load the initrd data into /dev/ram0. Execute it as initrd
		 * unless /dev/ram0 is supposed to be our actual root device,
		 * in that case the ram disk is just set up here, and gets
		 * mounted in the normal path.
		 */
		if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
			sys_unlink("/initrd.image");
			handle_initrd();
			return true;
		}
	}
	sys_unlink("/initrd.image");
	return false;
}
 value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Vlastimil Babka &lt;vbabka@suse.cz&gt;</td><td class='right'>2017-01-24 15:18:41 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-24 16:26:14 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/irda/ircomm?id=e47483bca2cc59a4593b37a270b16ee42b1d9f08'>e47483bca2cc59a4593b37a270b16ee42b1d9f08</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/irda/ircomm?id=e47483bca2cc59a4593b37a270b16ee42b1d9f08'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=e47483bca2cc59a4593b37a270b16ee42b1d9f08'>4bc66bd4f2f87a30d231068468d29900685fb45f</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/irda/ircomm?id=e47483bca2cc59a4593b37a270b16ee42b1d9f08'>net/irda/ircomm</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/irda/ircomm?id=5ce9bfef1d27944c119a397a9d827bef795487ce'>5ce9bfef1d27944c119a397a9d827bef795487ce</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/irda/ircomm?id=e47483bca2cc59a4593b37a270b16ee42b1d9f08&amp;id2=5ce9bfef1d27944c119a397a9d827bef795487ce'>diff</a>)</td></tr></table>
<div class='commit-subject'>mm, page_alloc: fix premature OOM when racing with cpuset mems update</div><div class='commit-msg'>Ganapatrao Kulkarni reported that the LTP test cpuset01 in stress mode
triggers OOM killer in few seconds, despite lots of free memory.  The
test attempts to repeatedly fault in memory in one process in a cpuset,
while changing allowed nodes of the cpuset between 0 and 1 in another
process.

The problem comes from insufficient protection against cpuset changes,
which can cause get_page_from_freelist() to consider all zones as
non-eligible due to nodemask and/or current-&gt;mems_allowed.  This was
masked in the past by sufficient retries, but since commit 682a3385e773
("mm, page_alloc: inline the fast path of the zonelist iterator") we fix
the preferred_zoneref once, and don't iterate over the whole zonelist in
further attempts, thus the only eligible zones might be placed in the
zonelist before our starting point and we always miss them.

A previous patch fixed this problem for current-&gt;mems_allowed.  However,
cpuset changes also update the task's mempolicy nodemask.  The fix has
two parts.  We have to repeat the preferred_zoneref search when we
detect cpuset update by way of seqcount, and we have to check the
seqcount before considering OOM.

[akpm@linux-foundation.org: fix typo in comment]
Link: http://lkml.kernel.org/r/20170120103843.24587-5-vbabka@suse.cz
Fixes: c33d6c06f60f ("mm, page_alloc: avoid looking up the first zone in a zonelist twice")
Signed-off-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Reported-by: Ganapatrao Kulkarni &lt;gpkulkarni@gmail.com&gt;
Acked-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Hillf Danton &lt;hillf.zj@alibaba-inc.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=e47483bca2cc59a4593b37a270b16ee42b1d9f08'>Diffstat</a> (limited to 'net/irda/ircomm')</div><table summary='diffstat' class='diffstat'>