Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 822 insertions, 0 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
new file mode 100644
index 000000000..f6f75d206
--- /dev/null
+++ b/fs/proc/array.c
@@ -0,0 +1,822 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/proc/array.c
+ *
+ *  Copyright (C) 1992  by Linus Torvalds
+ *  based on ideas by Darren Senn
+ *
+ * Fixes:
+ * Michael. K. Johnson: stat,statm extensions.
+ *                      <johnsonm@stolaf.edu>
+ *
+ * Pauline Middelink :  Made cmdline,envline only break at '\0's, to
+ *                      make sure SET_PROCTITLE works. Also removed
+ *                      bad '!' which forced address recalculation for
+ *                      EVERY character on the current page.
+ *                      <middelin@polyware.iaf.nl>
+ *
+ * Danny ter Haar    :	added cpuinfo
+ *			<dth@cistron.nl>
+ *
+ * Alessandro Rubini :  profile extension.
+ *                      <rubini@ipvvis.unipv.it>
+ *
+ * Jeff Tranter      :  added BogoMips field to cpuinfo
+ *                      <Jeff_Tranter@Mitel.COM>
+ *
+ * Bruno Haible      :  remove 4K limit for the maps file
+ *			<haible@ma2s2.mathematik.uni-karlsruhe.de>
+ *
+ * Yves Arrouye      :  remove removal of trailing spaces in get_array.
+ *			<Yves.Arrouye@marin.fdn.fr>
+ *
+ * Jerome Forissier  :  added per-CPU time information to /proc/stat
+ *                      and /proc/<pid>/cpu extension
+ *                      <forissier@isia.cma.fr>
+ *			- Incorporation and non-SMP safe operation
+ *			of forissier patch in 2.1.78 by
+ *			Hans Marcus <crowbar@concepts.nl>
+ *
+ * aeb@cwi.nl        :  /proc/partitions
+ *
+ *
+ * Alan Cox	     :  security fixes.
+ *			<alan@lxorguk.ukuu.org.uk>
+ *
+ * Al Viro           :  safe handling of mm_struct
+ *
+ * Gerhard Wichert   :  added BIGMEM support
+ * Siemens AG           <Gerhard.Wichert@pdb.siemens.de>
+ *
+ * Al Viro & Jeff Garzik :  moved most of the thing into base.c and
+ *			 :  proc_misc.c. The rest may eventually go into
+ *			 :  base.c too.
+ */
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/hex.h>
+#include <linux/time.h>
+#include <linux/time_namespace.h>
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/tty.h>
+#include <linux/string.h>
+#include <linux/mman.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/numa_balancing.h>
+#include <linux/sched/task_stack.h>
+#include <linux/sched/task.h>
+#include <linux/sched/cputime.h>
+#include <linux/proc_fs.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+#include <linux/smp.h>
+#include <linux/signal.h>
+#include <linux/highmem.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/times.h>
+#include <linux/cpuset.h>
+#include <linux/rcupdate.h>
+#include <linux/delayacct.h>
+#include <linux/seq_file.h>
+#include <linux/pid_namespace.h>
+#include <linux/prctl.h>
+#include <linux/ptrace.h>
+#include <linux/string_helpers.h>
+#include <linux/user_namespace.h>
+#include <linux/fs_struct.h>
+#include <linux/kthread.h>
+#include <linux/mmu_context.h>
+
+#include <asm/processor.h>
+#include "internal.h"
+
+void proc_task_name(struct seq_file *m, struct task_struct *p, bool escape)
+{
+	char tcomm[64];
+
+	/*
+	 * Test before PF_KTHREAD because all workqueue worker threads are
+	 * kernel threads.
+	 */
+	if (p->flags & PF_WQ_WORKER)
+		wq_worker_comm(tcomm, sizeof(tcomm), p);
+	else if (p->flags & PF_KTHREAD)
+		get_kthread_comm(tcomm, sizeof(tcomm), p);
+	else
+		get_task_comm(tcomm, p);
+
+	if (escape)
+		seq_escape_str(m, tcomm, ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
+	else
+		seq_printf(m, "%.64s", tcomm);
+}
+
+/*
+ * The task state array is a strange "bitmap" of
+ * reasons to sleep. Thus "running" is zero, and
+ * you can test for combinations of others with
+ * simple bit tests.
+ */
+static const char * const task_state_array[] = {
+
+	/* states in TASK_REPORT: */
+	"R (running)",		/* 0x00 */
+	"S (sleeping)",		/* 0x01 */
+	"D (disk sleep)",	/* 0x02 */
+	"T (stopped)",		/* 0x04 */
+	"t (tracing stop)",	/* 0x08 */
+	"X (dead)",		/* 0x10 */
+	"Z (zombie)",		/* 0x20 */
+	"P (parked)",		/* 0x40 */
+
+	/* states beyond TASK_REPORT: */
+	"I (idle)",		/* 0x80 */
+};
+
+static inline const char *get_task_state(struct task_struct *tsk)
+{
+	BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != ARRAY_SIZE(task_state_array));
+	return task_state_array[task_state_index(tsk)];
+}
+
+static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
+				struct pid *pid, struct task_struct *p)
+{
+	struct user_namespace *user_ns = seq_user_ns(m);
+	struct group_info *group_info;
+	int g, umask = -1;
+	struct task_struct *tracer;
+	const struct cred *cred;
+	pid_t ppid, tpid = 0, tgid, ngid;
+	unsigned int max_fds = 0;
+
+	rcu_read_lock();
+	tracer = ptrace_parent(p);
+	if (tracer)
+		tpid = task_pid_nr_ns(tracer, ns);
+
+	ppid = task_ppid_nr_ns(p, ns);
+	tgid = task_tgid_nr_ns(p, ns);
+	ngid = task_numa_group_id(p);
+	cred = get_task_cred(p);
+
+	task_lock(p);
+	if (p->real_fs)
+		umask = p->real_fs->umask;
+	if (p->files)
+		max_fds = files_fdtable(p->files)->max_fds;
+	task_unlock(p);
+	rcu_read_unlock();
+
+	if (umask >= 0)
+		seq_printf(m, "Umask:\t%#04o\n", umask);
+	seq_puts(m, "State:\t");
+	seq_puts(m, get_task_state(p));
+
+	seq_put_decimal_ull(m, "\nTgid:\t", tgid);
+	seq_put_decimal_ull(m, "\nNgid:\t", ngid);
+	seq_put_decimal_ull(m, "\nPid:\t", pid_nr_ns(pid, ns));
+	seq_put_decimal_ull(m, "\nPPid:\t", ppid);
+	seq_put_decimal_ull(m, "\nTracerPid:\t", tpid);
+	seq_put_decimal_ull(m, "\nUid:\t", from_kuid_munged(user_ns, cred->uid));
+	seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->euid));
+	seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->suid));
+	seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->fsuid));
+	seq_put_decimal_ull(m, "\nGid:\t", from_kgid_munged(user_ns, cred->gid));
+	seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->egid));
+	seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->sgid));
+	seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->fsgid));
+	seq_put_decimal_ull(m, "\nFDSize:\t", max_fds);
+
+	seq_puts(m, "\nGroups:\t");
+	group_info = cred->group_info;
+	for (g = 0; g < group_info->ngroups; g++)
+		seq_put_decimal_ull(m, g ? " " : "",
+				from_kgid_munged(user_ns, group_info->gid[g]));
+	put_cred(cred);
+	/* Trailing space shouldn't have been added in the first place. */
+	seq_putc(m, ' ');
+
+#ifdef CONFIG_PID_NS
+	seq_puts(m, "\nNStgid:");
+	for (g = ns->level; g <= pid->level; g++)
+		seq_put_decimal_ull(m, "\t", task_tgid_nr_ns(p, pid->numbers[g].ns));
+	seq_puts(m, "\nNSpid:");
+	for (g = ns->level; g <= pid->level; g++)
+		seq_put_decimal_ull(m, "\t", task_pid_nr_ns(p, pid->numbers[g].ns));
+	seq_puts(m, "\nNSpgid:");
+	for (g = ns->level; g <= pid->level; g++)
+		seq_put_decimal_ull(m, "\t", task_pgrp_nr_ns(p, pid->numbers[g].ns));
+	seq_puts(m, "\nNSsid:");
+	for (g = ns->level; g <= pid->level; g++)
+		seq_put_decimal_ull(m, "\t", task_session_nr_ns(p, pid->numbers[g].ns));
+#endif
+	seq_putc(m, '\n');
+
+	seq_printf(m, "Kthread:\t%c\n", p->flags & PF_KTHREAD ? '1' : '0');
+}
+
+void render_sigset_t(struct seq_file *m, const char *header,
+				sigset_t *set)
+{
+	int i;
+
+	seq_puts(m, header);
+
+	i = _NSIG;
+	do {
+		int x = 0;
+
+		i -= 4;
+		if (sigismember(set, i+1)) x |= 1;
+		if (sigismember(set, i+2)) x |= 2;
+		if (sigismember(set, i+3)) x |= 4;
+		if (sigismember(set, i+4)) x |= 8;
+		seq_putc(m, hex_asc[x]);
+	} while (i >= 4);
+
+	seq_putc(m, '\n');
+}
+
+static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *sigign,
+				    sigset_t *sigcatch)
+{
+	struct k_sigaction *k;
+	int i;
+
+	k = p->sighand->action;
+	for (i = 1; i <= _NSIG; ++i, ++k) {
+		if (k->sa.sa_handler == SIG_IGN)
+			sigaddset(sigign, i);
+		else if (k->sa.sa_handler != SIG_DFL)
+			sigaddset(sigcatch, i);
+	}
+}
+
+static inline void task_sig(struct seq_file *m, struct task_struct *p)
+{
+	unsigned long flags;
+	sigset_t pending, shpending, blocked, ignored, caught;
+	int num_threads = 0;
+	unsigned int qsize = 0;
+	unsigned long qlim = 0;
+
+	sigemptyset(&pending);
+	sigemptyset(&shpending);
+	sigemptyset(&blocked);
+	sigemptyset(&ignored);
+	sigemptyset(&caught);
+
+	if (lock_task_sighand(p, &flags)) {
+		pending = p->pending.signal;
+		shpending = p->signal->shared_pending.signal;
+		blocked = p->blocked;
+		collect_sigign_sigcatch(p, &ignored, &caught);
+		num_threads = get_nr_threads(p);
+		rcu_read_lock();
+		qsize = get_rlimit_value(task_ucounts(p), UCOUNT_RLIMIT_SIGPENDING);
+		rcu_read_unlock();
+		qlim = task_rlimit(p, RLIMIT_SIGPENDING);
+		unlock_task_sighand(p, &flags);
+	}
+
+	seq_put_decimal_ull(m, "Threads:\t", num_threads);
+	seq_put_decimal_ull(m, "\nSigQ:\t", qsize);
+	seq_put_decimal_ull(m, "/", qlim);
+
+	/* render them all */
+	render_sigset_t(m, "\nSigPnd:\t", &pending);
+	render_sigset_t(m, "ShdPnd:\t", &shpending);
+	render_sigset_t(m, "SigBlk:\t", &blocked);
+	render_sigset_t(m, "SigIgn:\t", &ignored);
+	render_sigset_t(m, "SigCgt:\t", &caught);
+}
+
+static void render_cap_t(struct seq_file *m, const char *header,
+			kernel_cap_t *a)
+{
+	seq_puts(m, header);
+	seq_put_hex_ll(m, NULL, a->val, 16);
+	seq_putc(m, '\n');
+}
+
+static inline void task_cap(struct seq_file *m, struct task_struct *p)
+{
+	const struct cred *cred;
+	kernel_cap_t cap_inheritable, cap_permitted, cap_effective,
+			cap_bset, cap_ambient;
+
+	rcu_read_lock();
+	cred = __task_cred(p);
+	cap_inheritable	= cred->cap_inheritable;
+	cap_permitted	= cred->cap_permitted;
+	cap_effective	= cred->cap_effective;
+	cap_bset	= cred->cap_bset;
+	cap_ambient	= cred->cap_ambient;
+	rcu_read_unlock();
+
+	render_cap_t(m, "CapInh:\t", &cap_inheritable);
+	render_cap_t(m, "CapPrm:\t", &cap_permitted);
+	render_cap_t(m, "CapEff:\t", &cap_effective);
+	render_cap_t(m, "CapBnd:\t", &cap_bset);
+	render_cap_t(m, "CapAmb:\t", &cap_ambient);
+}
+
+static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
+{
+	seq_put_decimal_ull(m, "NoNewPrivs:\t", task_no_new_privs(p));
+#ifdef CONFIG_SECCOMP
+	seq_put_decimal_ull(m, "\nSeccomp:\t", p->seccomp.mode);
+#ifdef CONFIG_SECCOMP_FILTER
+	seq_put_decimal_ull(m, "\nSeccomp_filters:\t",
+			    atomic_read(&p->seccomp.filter_count));
+#endif
+#endif
+	seq_puts(m, "\nSpeculation_Store_Bypass:\t");
+	switch (arch_prctl_spec_ctrl_get(p, PR_SPEC_STORE_BYPASS)) {
+	case -EINVAL:
+		seq_puts(m, "unknown");
+		break;
+	case PR_SPEC_NOT_AFFECTED:
+		seq_puts(m, "not vulnerable");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE:
+		seq_puts(m, "thread force mitigated");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_DISABLE:
+		seq_puts(m, "thread mitigated");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_ENABLE:
+		seq_puts(m, "thread vulnerable");
+		break;
+	case PR_SPEC_DISABLE:
+		seq_puts(m, "globally mitigated");
+		break;
+	default:
+		seq_puts(m, "vulnerable");
+		break;
+	}
+
+	seq_puts(m, "\nSpeculationIndirectBranch:\t");
+	switch (arch_prctl_spec_ctrl_get(p, PR_SPEC_INDIRECT_BRANCH)) {
+	case -EINVAL:
+		seq_puts(m, "unsupported");
+		break;
+	case PR_SPEC_NOT_AFFECTED:
+		seq_puts(m, "not affected");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE:
+		seq_puts(m, "conditional force disabled");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_DISABLE:
+		seq_puts(m, "conditional disabled");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_ENABLE:
+		seq_puts(m, "conditional enabled");
+		break;
+	case PR_SPEC_ENABLE:
+		seq_puts(m, "always enabled");
+		break;
+	case PR_SPEC_DISABLE:
+		seq_puts(m, "always disabled");
+		break;
+	default:
+		seq_puts(m, "unknown");
+		break;
+	}
+	seq_putc(m, '\n');
+}
+
+static inline void task_context_switch_counts(struct seq_file *m,
+						struct task_struct *p)
+{
+	seq_put_decimal_ull(m, "voluntary_ctxt_switches:\t", p->nvcsw);
+	seq_put_decimal_ull(m, "\nnonvoluntary_ctxt_switches:\t", p->nivcsw);
+	seq_putc(m, '\n');
+}
+
+static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
+{
+	seq_printf(m, "Cpus_allowed:\t%*pb\n",
+		   cpumask_pr_args(&task->cpus_mask));
+	seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
+		   cpumask_pr_args(&task->cpus_mask));
+}
+
+static inline void task_core_dumping(struct seq_file *m, struct task_struct *task)
+{
+	seq_put_decimal_ull(m, "CoreDumping:\t", !!task->signal->core_state);
+	seq_putc(m, '\n');
+}
+
+static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm)
+{
+	bool thp_enabled = IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE);
+
+	if (thp_enabled)
+		thp_enabled = !mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm);
+	seq_printf(m, "THP_enabled:\t%d\n", thp_enabled);
+}
+
+static inline void task_untag_mask(struct seq_file *m, struct mm_struct *mm)
+{
+	seq_printf(m, "untag_mask:\t%#lx\n", mm_untag_mask(mm));
+}
+
+__weak void arch_proc_pid_thread_features(struct seq_file *m,
+					  struct task_struct *task)
+{
+}
+
+int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task)
+{
+	struct mm_struct *mm = get_task_mm(task);
+
+	seq_puts(m, "Name:\t");
+	proc_task_name(m, task, true);
+	seq_putc(m, '\n');
+
+	task_state(m, ns, pid, task);
+
+	if (mm) {
+		task_mem(m, mm);
+		task_core_dumping(m, task);
+		task_thp_status(m, mm);
+		task_untag_mask(m, mm);
+		mmput(mm);
+	}
+	task_sig(m, task);
+	task_cap(m, task);
+	task_seccomp(m, task);
+	task_cpus_allowed(m, task);
+	cpuset_task_status_allowed(m, task);
+	task_context_switch_counts(m, task);
+	arch_proc_pid_thread_features(m, task);
+	return 0;
+}
+
+static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task, int whole)
+{
+	unsigned long vsize, eip, esp, wchan = 0;
+	int priority, nice;
+	int tty_pgrp = -1, tty_nr = 0;
+	sigset_t sigign, sigcatch;
+	char state;
+	pid_t ppid = 0, pgid = -1, sid = -1;
+	int num_threads = 0;
+	int permitted;
+	struct mm_struct *mm;
+	unsigned long long start_time;
+	unsigned long cmin_flt, cmaj_flt, min_flt, maj_flt;
+	u64 cutime, cstime, cgtime, utime, stime, gtime;
+	unsigned long rsslim = 0;
+	unsigned long flags;
+	int exit_code = task->exit_code;
+	struct signal_struct *sig = task->signal;
+	int ret;
+
+	ret = down_read_killable(&task->signal->exec_update_lock);
+	if (ret)
+		return ret;
+
+	state = *get_task_state(task);
+	vsize = eip = esp = 0;
+	permitted = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS | PTRACE_MODE_NOAUDIT);
+	mm = get_task_mm(task);
+	if (mm) {
+		vsize = task_vsize(mm);
+		/*
+		 * esp and eip are intentionally zeroed out.  There is no
+		 * non-racy way to read them without freezing the task.
+		 * Programs that need reliable values can use ptrace(2).
+		 *
+		 * The only exception is if the task is core dumping because
+		 * a program is not able to use ptrace(2) in that case. It is
+		 * safe because the task has stopped executing permanently.
+		 */
+		if (permitted && (task->flags & (PF_EXITING|PF_DUMPCORE|PF_POSTCOREDUMP))) {
+			if (try_get_task_stack(task)) {
+				eip = KSTK_EIP(task);
+				esp = KSTK_ESP(task);
+				put_task_stack(task);
+			}
+		}
+	}
+
+	sigemptyset(&sigign);
+	sigemptyset(&sigcatch);
+
+	if (lock_task_sighand(task, &flags)) {
+		if (sig->tty) {
+			struct pid *pgrp = tty_get_pgrp(sig->tty);
+			tty_pgrp = pid_nr_ns(pgrp, ns);
+			put_pid(pgrp);
+			tty_nr = new_encode_dev(tty_devnum(sig->tty));
+		}
+
+		num_threads = get_nr_threads(task);
+		collect_sigign_sigcatch(task, &sigign, &sigcatch);
+
+		rsslim = READ_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
+
+		if (whole) {
+			if (sig->flags & (SIGNAL_GROUP_EXIT | SIGNAL_STOP_STOPPED))
+				exit_code = sig->group_exit_code;
+		}
+
+		sid = task_session_nr_ns(task, ns);
+		ppid = task_ppid_nr_ns(task, ns);
+		pgid = task_pgrp_nr_ns(task, ns);
+
+		unlock_task_sighand(task, &flags);
+	}
+
+	if (permitted && (!whole || num_threads < 2))
+		wchan = !task_is_running(task);
+
+	scoped_guard(rcu) {
+		scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) {
+			cmin_flt = sig->cmin_flt;
+			cmaj_flt = sig->cmaj_flt;
+			cutime = sig->cutime;
+			cstime = sig->cstime;
+			cgtime = sig->cgtime;
+
+			if (whole) {
+				struct task_struct *t;
+
+				min_flt = sig->min_flt;
+				maj_flt = sig->maj_flt;
+				gtime = sig->gtime;
+
+				__for_each_thread(sig, t) {
+					min_flt += t->min_flt;
+					maj_flt += t->maj_flt;
+					gtime += task_gtime(t);
+				}
+			}
+		}
+	}
+
+	if (whole) {
+		thread_group_cputime_adjusted(task, &utime, &stime);
+	} else {
+		task_cputime_adjusted(task, &utime, &stime);
+		min_flt = task->min_flt;
+		maj_flt = task->maj_flt;
+		gtime = task_gtime(task);
+	}
+
+	/* scale priority and nice values from timeslices to -20..20 */
+	/* to make it look like a "normal" Unix priority/nice value  */
+	priority = task_prio(task);
+	nice = task_nice(task);
+
+	/* apply timens offset for boottime and convert nsec -> ticks */
+	start_time =
+		nsec_to_clock_t(timens_add_boottime_ns(task->start_boottime));
+
+	seq_put_decimal_ull(m, "", pid_nr_ns(pid, ns));
+	seq_puts(m, " (");
+	proc_task_name(m, task, false);
+	seq_puts(m, ") ");
+	seq_putc(m, state);
+	seq_put_decimal_ll(m, " ", ppid);
+	seq_put_decimal_ll(m, " ", pgid);
+	seq_put_decimal_ll(m, " ", sid);
+	seq_put_decimal_ll(m, " ", tty_nr);
+	seq_put_decimal_ll(m, " ", tty_pgrp);
+	seq_put_decimal_ull(m, " ", task->flags);
+	seq_put_decimal_ull(m, " ", min_flt);
+	seq_put_decimal_ull(m, " ", cmin_flt);
+	seq_put_decimal_ull(m, " ", maj_flt);
+	seq_put_decimal_ull(m, " ", cmaj_flt);
+	seq_put_decimal_ull(m, " ", nsec_to_clock_t(utime));
+	seq_put_decimal_ull(m, " ", nsec_to_clock_t(stime));
+	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cutime));
+	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cstime));
+	seq_put_decimal_ll(m, " ", priority);
+	seq_put_decimal_ll(m, " ", nice);
+	seq_put_decimal_ll(m, " ", num_threads);
+	seq_put_decimal_ull(m, " ", 0);
+	seq_put_decimal_ull(m, " ", start_time);
+	seq_put_decimal_ull(m, " ", vsize);
+	seq_put_decimal_ull(m, " ", mm ? get_mm_rss(mm) : 0);
+	seq_put_decimal_ull(m, " ", rsslim);
+	seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->start_code : 1) : 0);
+	seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->end_code : 1) : 0);
+	seq_put_decimal_ull(m, " ", (permitted && mm) ? mm->start_stack : 0);
+	seq_put_decimal_ull(m, " ", esp);
+	seq_put_decimal_ull(m, " ", eip);
+	/* The signal information here is obsolete.
+	 * It must be decimal for Linux 2.0 compatibility.
+	 * Use /proc/#/status for real-time signals.
+	 */
+	seq_put_decimal_ull(m, " ", task->pending.signal.sig[0] & 0x7fffffffUL);
+	seq_put_decimal_ull(m, " ", task->blocked.sig[0] & 0x7fffffffUL);
+	seq_put_decimal_ull(m, " ", sigign.sig[0] & 0x7fffffffUL);
+	seq_put_decimal_ull(m, " ", sigcatch.sig[0] & 0x7fffffffUL);
+
+	/*
+	 * We used to output the absolute kernel address, but that's an
+	 * information leak - so instead we show a 0/1 flag here, to signal
+	 * to user-space whether there's a wchan field in /proc/PID/wchan.
+	 *
+	 * This works with older implementations of procps as well.
+	 */
+	seq_put_decimal_ull(m, " ", wchan);
+
+	seq_put_decimal_ull(m, " ", 0);
+	seq_put_decimal_ull(m, " ", 0);
+	seq_put_decimal_ll(m, " ", task->exit_signal);
+	seq_put_decimal_ll(m, " ", task_cpu(task));
+	seq_put_decimal_ull(m, " ", task->rt_priority);
+	seq_put_decimal_ull(m, " ", task->policy);
+	seq_put_decimal_ull(m, " ", delayacct_blkio_ticks(task));
+	seq_put_decimal_ull(m, " ", nsec_to_clock_t(gtime));
+	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cgtime));
+
+	if (mm && permitted) {
+		seq_put_decimal_ull(m, " ", mm->start_data);
+		seq_put_decimal_ull(m, " ", mm->end_data);
+		seq_put_decimal_ull(m, " ", mm->start_brk);
+		seq_put_decimal_ull(m, " ", mm->arg_start);
+		seq_put_decimal_ull(m, " ", mm->arg_end);
+		seq_put_decimal_ull(m, " ", mm->env_start);
+		seq_put_decimal_ull(m, " ", mm->env_end);
+	} else
+		seq_puts(m, " 0 0 0 0 0 0 0");
+
+	if (permitted)
+		seq_put_decimal_ll(m, " ", exit_code);
+	else
+		seq_puts(m, " 0");
+
+	seq_putc(m, '\n');
+	up_read(&task->signal->exec_update_lock);
+	if (mm)
+		mmput(mm);
+	return 0;
+}
+
+int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task)
+{
+	return do_task_stat(m, ns, pid, task, 0);
+}
+
+int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task)
+{
+	return do_task_stat(m, ns, pid, task, 1);
+}
+
+int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task)
+{
+	struct mm_struct *mm = get_task_mm(task);
+
+	if (mm) {
+		unsigned long size;
+		unsigned long resident = 0;
+		unsigned long shared = 0;
+		unsigned long text = 0;
+		unsigned long data = 0;
+
+		size = task_statm(mm, &shared, &text, &data, &resident);
+		mmput(mm);
+
+		/*
+		 * For quick read, open code by putting numbers directly
+		 * expected format is
+		 * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
+		 *               size, resident, shared, text, data);
+		 */
+		seq_put_decimal_ull(m, "", size);
+		seq_put_decimal_ull(m, " ", resident);
+		seq_put_decimal_ull(m, " ", shared);
+		seq_put_decimal_ull(m, " ", text);
+		seq_put_decimal_ull(m, " ", 0);
+		seq_put_decimal_ull(m, " ", data);
+		seq_put_decimal_ull(m, " ", 0);
+		seq_putc(m, '\n');
+	} else {
+		seq_write(m, "0 0 0 0 0 0 0\n", 14);
+	}
+	return 0;
+}
+
+#ifdef CONFIG_PROC_CHILDREN
+static struct pid *
+get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
+{
+	struct task_struct *start, *task;
+	struct pid *pid = NULL;
+
+	read_lock(&tasklist_lock);
+
+	start = pid_task(proc_pid(inode), PIDTYPE_PID);
+	if (!start)
+		goto out;
+
+	/*
+	 * Lets try to continue searching first, this gives
+	 * us significant speedup on children-rich processes.
+	 */
+	if (pid_prev) {
+		task = pid_task(pid_prev, PIDTYPE_PID);
+		if (task && task->real_parent == start &&
+		    !(list_empty(&task->sibling))) {
+			if (list_is_last(&task->sibling, &start->children))
+				goto out;
+			task = list_first_entry(&task->sibling,
+						struct task_struct, sibling);
+			pid = get_pid(task_pid(task));
+			goto out;
+		}
+	}
+
+	/*
+	 * Slow search case.
+	 *
+	 * We might miss some children here if children
+	 * are exited while we were not holding the lock,
+	 * but it was never promised to be accurate that
+	 * much.
+	 *
+	 * "Just suppose that the parent sleeps, but N children
+	 *  exit after we printed their tids. Now the slow paths
+	 *  skips N extra children, we miss N tasks." (c)
+	 *
+	 * So one need to stop or freeze the leader and all
+	 * its children to get a precise result.
+	 */
+	list_for_each_entry(task, &start->children, sibling) {
+		if (pos-- == 0) {
+			pid = get_pid(task_pid(task));
+			break;
+		}
+	}
+
+out:
+	read_unlock(&tasklist_lock);
+	return pid;
+}
+
+static int children_seq_show(struct seq_file *seq, void *v)
+{
+	struct inode *inode = file_inode(seq->file);
+
+	seq_printf(seq, "%d ", pid_nr_ns(v, proc_pid_ns(inode->i_sb)));
+	return 0;
+}
+
+static void *children_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	return get_children_pid(file_inode(seq->file), NULL, *pos);
+}
+
+static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct pid *pid;
+
+	pid = get_children_pid(file_inode(seq->file), v, *pos + 1);
+	put_pid(v);
+
+	++*pos;
+	return pid;
+}
+
+static void children_seq_stop(struct seq_file *seq, void *v)
+{
+	put_pid(v);
+}
+
+static const struct seq_operations children_seq_ops = {
+	.start	= children_seq_start,
+	.next	= children_seq_next,
+	.stop	= children_seq_stop,
+	.show	= children_seq_show,
+};
+
+static int children_seq_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &children_seq_ops);
+}
+
+const struct file_operations proc_tid_children_operations = {
+	.open    = children_seq_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release,
+};
+#endif /* CONFIG_PROC_CHILDREN */