#ifndef _GNU_SOURCE
# define _GNU_SOURCE
#endif
#include <sched.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/resource.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>

#include "proc.h"
#include "die.h"

void cpu_affinity(int cpu)
{
	int ret;
	cpu_set_t cpu_bitmask;

	CPU_ZERO(&cpu_bitmask);
	CPU_SET(cpu, &cpu_bitmask);

	ret = sched_setaffinity(getpid(), sizeof(cpu_bitmask),
				&cpu_bitmask);
	if (ret)
		panic("Can't set this cpu affinity!\n");
}

int set_proc_prio(int priority)
{
	int ret = setpriority(PRIO_PROCESS, getpid(), priority);
	if (ret)
		panic("Can't set nice val to %i!\n", priority);

	return 0;
}

int set_sched_status(int policy, int priority)
{
	int ret, min_prio, max_prio;
	struct sched_param sp;

	max_prio = sched_get_priority_max(policy);
	min_prio = sched_get_priority_min(policy);

	if (max_prio == -1 || min_prio == -1)
		printf("Cannot determine scheduler prio limits!\n");
	else if (priority < min_prio)
		priority = min_prio;
	else if (priority > max_prio)
		priority = max_prio;

	memset(&sp, 0, sizeof(sp));
	sp.sched_priority = priority;

	ret = sched_setscheduler(getpid(), policy, &sp);
	if (ret) {
		printf("Cannot set scheduler policy!\n");
		return -EINVAL;
	}

	ret = sched_setparam(getpid(), &sp);
	if (ret) {
		printf("Cannot set scheduler prio!\n");
		return -EINVAL;
	}

	return 0;
}

ssize_t proc_get_cmdline(unsigned int pid, char *cmdline, size_t len)
{
	ssize_t ret;
	char path[1024];

	snprintf(path, sizeof(path), "/proc/%u/exe", pid);
	ret = readlink(path, cmdline, len - 1);
	if (ret < 0)
		cmdline[0] = '\0';
	else
		cmdline[ret] = '\0';

	return ret;
}

static int match_pid_by_inode(pid_t pid, ino_t ino)
{
	struct dirent *ent;
	char path[1024];
	DIR *dir;

	if (snprintf(path, sizeof(path), "/proc/%u/fd", pid) == -1)
		panic("giant process name! %u\n", pid);

	dir = opendir(path);
	if (!dir)
		return -1;

	while ((ent = readdir(dir))) {
		struct stat statbuf;

		if (snprintf(path, sizeof(path), "/proc/%u/fd/%s",
			     pid, ent->d_name) < 0)
			continue;

		if (stat(path, &statbuf) < 0)
			continue;

		if (S_ISSOCK(statbuf.st_mode) && ino == statbuf.st_ino) {
			closedir(dir);
			return 0;
		}
	}

	closedir(dir);
	return -1;
}

int proc_find_by_inode(ino_t ino, char *cmdline, size_t len, pid_t *pid)
{
	struct dirent *ent;
	DIR *dir;

	if (ino <= 0) {
		cmdline[0] = '\0';
		return 0;
	}

	dir = opendir("/proc");
	if (!dir)
		panic("Cannot open /proc: %s\n", strerror(errno));

	while ((ent = readdir(dir))) {
		int ret;
		char *end;
		const char *name = ent->d_name;
		pid_t cur_pid = strtoul(name, &end, 10);

		/* not a PID */
		if (cur_pid == 0 && end == name)
			continue;

		ret = match_pid_by_inode(cur_pid, ino);
		if (!ret) {
			ret = proc_get_cmdline(cur_pid, cmdline, len);
			if (ret < 0)
				panic("Failed to get process cmdline: %s\n", strerror(errno));

			closedir(dir);
			*pid = cur_pid;
			return ret;
		}
	}

	closedir(dir);
	return -1;
}

int proc_exec(const char *proc, char *const argv[])
{
	int status;
	pid_t pid;

	pid = fork();
	if (pid < 0) {
		perror("fork");
		return -1;
	} else if (pid == 0) {
		if (execvp(proc, argv) < 0)
			fprintf(stderr, "Failed to exec: %s\n", proc);
		_exit(1);
	}

	if (waitpid(pid, &status, 0) < 0) {
		perror("waitpid");
		return -2;
	}

	if (!WIFEXITED(status))
		return -WEXITSTATUS(status);

	return 0;
}

bool proc_exists(pid_t pid)
{
	struct stat statbuf;
	char path[1024];

	if (snprintf(path, sizeof(path), "/proc/%u", pid) < 0)
		return false;

	return stat(path, &statbuf) == 0;
}
a1fcb6d6dc0126b076aad062054c2637'>efivarfs</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/tools/testing/selftests/efivarfs?h=nds-private-remove&amp;id=566cf877a1fcb6d6dc0126b076aad062054c2637&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
 onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option 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>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/timers?h=nds-private-remove&amp;id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/tools/testing/selftests/timers?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>98fe974ee4e20121253de7f61fc8d01bdb3821c1</a> /<a href='/cgit.cgi/linux/net-next.git/tree/tools/testing/selftests/timers?h=nds-private-remove&amp;id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>tools/testing/selftests/timers</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/timers?h=nds-private-remove&amp;id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/tools/testing/selftests/timers?h=nds-private-remove&amp;id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e&amp;id2=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>diff</a>)</td></tr></table>
<div class='commit-subject'>drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()</div><div class='commit-msg'>I've seen this trigger twice now, where the i915_gem_object_to_ggtt()
call in intel_unpin_fb_obj() returns NULL, resulting in an oops
immediately afterwards as the (inlined) call to i915_vma_unpin_fence()
tries to dereference it.

It seems to be some race condition where the object is going away at
shutdown time, since both times happened when shutting down the X
server.  The call chains were different:

 - VT ioctl(KDSETMODE, KD_TEXT):

    intel_cleanup_plane_fb+0x5b/0xa0 [i915]
    drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper]
    intel_atomic_commit_tail+0x749/0xfe0 [i915]
    intel_atomic_commit+0x3cb/0x4f0 [i915]
    drm_atomic_commit+0x4b/0x50 [drm]
    restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper]
    drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper]
    drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper]
    intel_fbdev_set_par+0x18/0x70 [i915]
    fb_set_var+0x236/0x460
    fbcon_blank+0x30f/0x350
    do_unblank_screen+0xd2/0x1a0
    vt_ioctl+0x507/0x12a0
    tty_ioctl+0x355/0xc30
    do_vfs_ioctl+0xa3/0x5e0
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x13/0x94

 - i915 unpin_work workqueue:

    intel_unpin_work_fn+0x58/0x140 [i915]
    process_one_work+0x1f1/0x480
    worker_thread+0x48/0x4d0
    kthread+0x101/0x140

and this patch purely papers over the issue by adding a NULL pointer
check and a WARN_ON_ONCE() to avoid the oops that would then generally
make the machine unresponsive.

Other callers of i915_gem_object_to_ggtt() seem to also check for the
returned pointer being NULL and warn about it, so this clearly has
happened before in other places.

[ Reported it originally to the i915 developers on Jan 8, applying the
  ugly workaround on my own now after triggering the problem for the
  second time with no feedback.

  This is likely to be the same bug reported as

     https://bugs.freedesktop.org/show_bug.cgi?id=98829
     https://bugs.freedesktop.org/show_bug.cgi?id=99134

  which has a patch for the underlying problem, but it hasn't gotten to
  me, so I'm applying the workaround. ]

Cc: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@linux.intel.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&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/?h=nds-private-remove&amp;id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>Diffstat</a> (limited to 'tools/testing/selftests/timers')</div><table summary='diffstat' class='diffstat'>