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Commit b772b8e3 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull core fixes from Ingo Molnar:

 - workaround for gcc asm handling

 - futex race fixes

 - objtool build warning fix

 - two watchdog fixes: a crash fix (revert) and a bug fix for
   /proc/sys/kernel/watchdog_thresh handling.

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Prevent GCC from merging annotate_unreachable(), take 2
  objtool: Resync objtool's instruction decoder source code copy with the kernel's latest version
  watchdog/hardlockup/perf: Use atomics to track in-use cpu counter
  watchdog/harclockup/perf: Revert a33d4484 ("watchdog/hardlockup/perf: Simplify deferred event destroy")
  futex: Fix more put_pi_state() vs. exit_pi_state_list() races
parents 3131dc46 ec1e1b61

include/linux/compiler.h

+2 −2
Original line number Diff line number Diff line
@@ -191,13 +191,13 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, 
	asm("%c0:\n\t"							\

	    ".pushsection .discard.reachable\n\t"			\

	    ".long %c0b - .\n\t"					\

	    ".popsection\n\t" : : "i" (__LINE__));			\

	    ".popsection\n\t" : : "i" (__COUNTER__));			\

})

#define annotate_unreachable() ({					\

	asm("%c0:\n\t"							\

	    ".pushsection .discard.unreachable\n\t"			\

	    ".long %c0b - .\n\t"					\

	    ".popsection\n\t" : : "i" (__LINE__));			\

	    ".popsection\n\t" : : "i" (__COUNTER__));			\

})

#define ASM_UNREACHABLE							\

	"999:\n\t"							\

kernel/futex.c

+20 −3
Original line number Diff line number Diff line
@@ -903,11 +903,27 @@ void exit_pi_state_list(struct task_struct *curr) 
	 */

	raw_spin_lock_irq(&curr->pi_lock);

	while (!list_empty(head)) {



		next = head->next;

		pi_state = list_entry(next, struct futex_pi_state, list);

		key = pi_state->key;

		hb = hash_futex(&key);



		/*

		 * We can race against put_pi_state() removing itself from the

		 * list (a waiter going away). put_pi_state() will first

		 * decrement the reference count and then modify the list, so

		 * its possible to see the list entry but fail this reference

		 * acquire.

		 *

		 * In that case; drop the locks to let put_pi_state() make

		 * progress and retry the loop.

		 */

		if (!atomic_inc_not_zero(&pi_state->refcount)) {

			raw_spin_unlock_irq(&curr->pi_lock);

			cpu_relax();

			raw_spin_lock_irq(&curr->pi_lock);

			continue;

		}

		raw_spin_unlock_irq(&curr->pi_lock);



		spin_lock(&hb->lock);
@@ -918,8 +934,10 @@ void exit_pi_state_list(struct task_struct *curr) 
		 * task still owns the PI-state:

		 */

		if (head->next != next) {

			/* retain curr->pi_lock for the loop invariant */

			raw_spin_unlock(&pi_state->pi_mutex.wait_lock);

			spin_unlock(&hb->lock);

			put_pi_state(pi_state);

			continue;

		}
@@ -927,9 +945,8 @@ void exit_pi_state_list(struct task_struct *curr) 
		WARN_ON(list_empty(&pi_state->list));

		list_del_init(&pi_state->list);

		pi_state->owner = NULL;

		raw_spin_unlock(&curr->pi_lock);



		get_pi_state(pi_state);

		raw_spin_unlock(&curr->pi_lock);

		raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);

		spin_unlock(&hb->lock);

kernel/watchdog_hld.c

+10 −5
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#define pr_fmt(fmt) "NMI watchdog: " fmt



#include <linux/nmi.h>

#include <linux/atomic.h>

#include <linux/module.h>

#include <linux/sched/debug.h>
@@ -22,10 +23,11 @@ 
static DEFINE_PER_CPU(bool, hard_watchdog_warn);

static DEFINE_PER_CPU(bool, watchdog_nmi_touch);

static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);

static DEFINE_PER_CPU(struct perf_event *, dead_event);

static struct cpumask dead_events_mask;



static unsigned long hardlockup_allcpu_dumped;

static unsigned int watchdog_cpus;

static atomic_t watchdog_cpus = ATOMIC_INIT(0);



void arch_touch_nmi_watchdog(void)

{
@@ -189,7 +191,8 @@ void hardlockup_detector_perf_enable(void) 
	if (hardlockup_detector_event_create())

		return;



	if (!watchdog_cpus++)

	/* use original value for check */

	if (!atomic_fetch_inc(&watchdog_cpus))

		pr_info("Enabled. Permanently consumes one hw-PMU counter.\n");



	perf_event_enable(this_cpu_read(watchdog_ev));
@@ -204,8 +207,10 @@ void hardlockup_detector_perf_disable(void) 


	if (event) {

		perf_event_disable(event);

		this_cpu_write(watchdog_ev, NULL);

		this_cpu_write(dead_event, event);

		cpumask_set_cpu(smp_processor_id(), &dead_events_mask);

		watchdog_cpus--;

		atomic_dec(&watchdog_cpus);

	}

}
@@ -219,7 +224,7 @@ void hardlockup_detector_perf_cleanup(void) 
	int cpu;



	for_each_cpu(cpu, &dead_events_mask) {

		struct perf_event *event = per_cpu(watchdog_ev, cpu);

		struct perf_event *event = per_cpu(dead_event, cpu);



		/*

		 * Required because for_each_cpu() reports  unconditionally
@@ -227,7 +232,7 @@ void hardlockup_detector_perf_cleanup(void) 
		 */

		if (event)

			perf_event_release_kernel(event);

		per_cpu(watchdog_ev, cpu) = NULL;

		per_cpu(dead_event, cpu) = NULL;

	}

	cpumask_clear(&dead_events_mask);

}

tools/objtool/arch/x86/insn/gen-insn-attr-x86.awk

+1 −0
Original line number Diff line number Diff line 
#!/bin/awk -f

# SPDX-License-Identifier: GPL-2.0

# gen-insn-attr-x86.awk: Instruction attribute table generator

# Written by Masami Hiramatsu <mhiramat@redhat.com>

#