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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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887c5c12e8
sched_yield by a userspace may not actually cause scheduling in time-travel mode as no time has passed. In the case seen it appears to be a badly implemented userspace spinlock in ASAN. Unfortunately, with time-travel it causes an extreme slowdown or even deadlock depending on the kernel configuration (CONFIG_UML_MAX_USERSPACE_ITERATIONS). Work around it by accounting time to the process whenever it executes a sched_yield syscall. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250314130815.226872-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
94 lines
2.2 KiB
C
94 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2012 - 2014 Cisco Systems
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* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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*/
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#ifndef __TIMER_INTERNAL_H__
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#define __TIMER_INTERNAL_H__
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#include <linux/list.h>
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#include <asm/bug.h>
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#include <shared/timetravel.h>
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#define TIMER_MULTIPLIER 256
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#define TIMER_MIN_DELTA 500
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#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
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struct time_travel_event {
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unsigned long long time;
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void (*fn)(struct time_travel_event *d);
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struct list_head list;
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bool pending, onstack;
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};
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void time_travel_sleep(void);
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static inline void
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time_travel_set_event_fn(struct time_travel_event *e,
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void (*fn)(struct time_travel_event *d))
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{
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e->fn = fn;
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}
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void __time_travel_propagate_time(void);
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static inline void time_travel_propagate_time(void)
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{
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if (time_travel_mode == TT_MODE_EXTERNAL)
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__time_travel_propagate_time();
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}
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void __time_travel_wait_readable(int fd);
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static inline void time_travel_wait_readable(int fd)
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{
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if (time_travel_mode == TT_MODE_EXTERNAL)
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__time_travel_wait_readable(fd);
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}
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void time_travel_add_irq_event(struct time_travel_event *e);
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void time_travel_add_event_rel(struct time_travel_event *e,
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unsigned long long delay_ns);
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bool time_travel_del_event(struct time_travel_event *e);
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#else
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struct time_travel_event {
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};
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static inline void time_travel_sleep(void)
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{
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}
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/* this is a macro so the event/function need not exist */
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#define time_travel_set_event_fn(e, fn) do {} while (0)
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static inline void time_travel_propagate_time(void)
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{
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}
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static inline void time_travel_wait_readable(int fd)
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{
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}
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static inline void time_travel_add_irq_event(struct time_travel_event *e)
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{
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WARN_ON(1);
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}
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/*
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* not inlines so the data structure need not exist,
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* cause linker failures
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*/
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extern void time_travel_not_configured(void);
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#define time_travel_add_event_rel(...) time_travel_not_configured()
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#define time_travel_del_event(...) time_travel_not_configured()
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#endif /* CONFIG_UML_TIME_TRAVEL_SUPPORT */
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extern unsigned long tt_extra_sched_jiffies;
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/*
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* Without CONFIG_UML_TIME_TRAVEL_SUPPORT this is a linker error if used,
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* which is intentional since we really shouldn't link it in that case.
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*/
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void time_travel_ndelay(unsigned long nsec);
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#endif /* __TIMER_INTERNAL_H__ */
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