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LinuxKPI: update rcu_dereference_*() and lockdep_is_held()

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Update rcu_dereference_{check,protected}() to call the check and log
once if it fails and if the RCU debug sysctl is turned on.
Also add proper checks for conditions passed in to these functions.
For that implement linux_rcu_read_lock_held() (lots of help from wulf).

(While here also remove extraneous extern for function prototypes).

Update lockdep_is_held() to always be an inline function with argument
annotation so that we do no longer have unused variables
in callers which only call lockdep_is_held().

Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
Reviewed by:	wulf
Differential Revision:  https://reviews.freebsd.org/D46842
This commit is contained in:
Bjoern A. Zeeb 2024-09-29 00:35:04 +00:00
parent d55d5dd9f7
commit 5c92f84bb6
4 changed files with 97 additions and 23 deletions
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28
sys/compat/linuxkpi/common/include/linux/lockdep.h
View file

@ -70,17 +70,6 @@ struct pin_cookie {
#define lockdep_assert_none_held_once() do { } while (0)
static __inline bool
lockdep_is_held(void *__m)
{
struct lock_object *__lock;
struct thread *__td;
__lock = __m;
return (LOCK_CLASS(__lock)->lc_owner(__lock, &__td) != 0);
}
#define lockdep_is_held_type(_m, _t) lockdep_is_held(_m)
#else
#define lockdep_assert(cond) do { } while (0)
#define lockdep_assert_once(cond) do { } while (0)
@ -91,10 +80,23 @@ lockdep_is_held(void *__m)
#define lockdep_assert_held_once(m) do { (void)(m); } while (0)
#define lockdep_is_held(m) 1
#define lockdep_is_held_type(_m, _t) 1
#endif
static __inline bool
lockdep_is_held(void *__m __diagused)
{
#ifdef INVARIANTS
struct lock_object *__lock;
struct thread *__td;
__lock = __m;
return (LOCK_CLASS(__lock)->lc_owner(__lock, &__td) != 0);
#else
return (true);
#endif
}
#define lockdep_is_held_type(_m, _t) lockdep_is_held(_m)
#define might_lock(m) do { } while (0)
#define might_lock_read(m) do { } while (0)
#define might_lock_nested(m, n) do { } while (0)

57
sys/compat/linuxkpi/common/include/linux/rcupdate.h
View file

@ -1,6 +1,10 @@
/*-
* Copyright (c) 2016-2017 Mellanox Technologies, Ltd.
* All rights reserved.
* Copyright (c) 2024 The FreeBSD Foundation
*
* Portions of this software were developed by Björn Zeeb
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@ -26,11 +30,20 @@
#ifndef _LINUXKPI_LINUX_RCUPDATE_H_
#define _LINUXKPI_LINUX_RCUPDATE_H_
#include <sys/cdefs.h>
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <machine/atomic.h>
extern int linuxkpi_rcu_debug;
#define RCU_WARN_ONCE(c, ...) do { \
if (unlikely(linuxkpi_rcu_debug > 0)) \
WARN_ONCE((c), ##__VA_ARGS__); \
} while(0)
#define LINUX_KFREE_RCU_OFFSET_MAX 4096 /* exclusive */
/* BSD specific defines */
@ -61,6 +74,9 @@
linux_rcu_read_unlock(RCU_TYPE_REGULAR);\
} while (0)
#define rcu_read_lock_held(void) \
linux_rcu_read_lock_held(RCU_TYPE_REGULAR)
#define synchronize_rcu(void) do { \
linux_synchronize_rcu(RCU_TYPE_REGULAR); \
} while (0)
@ -79,14 +95,34 @@
#define rcu_access_pointer(p) \
((__typeof(*p) *)READ_ONCE(p))
#define rcu_dereference_protected(p, c) \
#define rcu_dereference(p) \
((__typeof(*p) *)READ_ONCE(p))
#define rcu_dereference(p) \
rcu_dereference_protected(p, 0)
#define __rcu_var_name(n, f, l) \
__CONCAT(__CONCAT(__CONCAT(rcu_, n), _), __COUNTER__)
#define rcu_dereference_check(p, c) \
rcu_dereference_protected(p, c)
#define __rcu_dereference_protected(p, c, n) \
({ \
RCU_WARN_ONCE(!(c), "%s:%d: condition for %s failed\n", \
__func__, __LINE__, __XSTRING(n)); \
rcu_dereference(p); \
})
#define rcu_dereference_protected(p, c) \
__rcu_dereference_protected((p), (c), \
__rcu_var_name(protected, __func__, __LINE__))
#define __rcu_dereference_check(p, c, n) \
({ \
__typeof(*p) *n = rcu_dereference(p); \
RCU_WARN_ONCE(!(c), "%s:%d: condition for %s failed\n", \
__func__, __LINE__, __XSTRING(n)); \
n; \
})
#define rcu_dereference_check(p, c) \
__rcu_dereference_check((p), (c) || rcu_read_lock_held(), \
__rcu_var_name(check, __func__, __LINE__))
#define rcu_dereference_raw(p) \
((__typeof(*p) *)READ_ONCE(p))
@ -113,11 +149,12 @@
/* prototypes */
extern void linux_call_rcu(unsigned type, struct rcu_head *ptr, rcu_callback_t func);
extern void linux_rcu_barrier(unsigned type);
extern void linux_rcu_read_lock(unsigned type);
extern void linux_rcu_read_unlock(unsigned type);
extern void linux_synchronize_rcu(unsigned type);
void linux_call_rcu(unsigned type, struct rcu_head *ptr, rcu_callback_t func);
void linux_rcu_barrier(unsigned type);
void linux_rcu_read_lock(unsigned type);
void linux_rcu_read_unlock(unsigned type);
bool linux_rcu_read_lock_held(unsigned);
void linux_synchronize_rcu(unsigned type);
/* Empty implementation for !DEBUG */
#define init_rcu_head(...)

4
sys/compat/linuxkpi/common/src/linux_compat.c
View file

@ -117,6 +117,10 @@ int linuxkpi_debug;
SYSCTL_INT(_compat_linuxkpi, OID_AUTO, debug, CTLFLAG_RWTUN,
&linuxkpi_debug, 0, "Set to enable pr_debug() prints. Clear to disable.");
int linuxkpi_rcu_debug;
SYSCTL_INT(_compat_linuxkpi, OID_AUTO, rcu_debug, CTLFLAG_RWTUN,
&linuxkpi_rcu_debug, 0, "Set to enable RCU warning. Clear to disable.");
int linuxkpi_warn_dump_stack = 0;
SYSCTL_INT(_compat_linuxkpi, OID_AUTO, warn_dump_stack, CTLFLAG_RWTUN,
&linuxkpi_warn_dump_stack, 0,

31
sys/compat/linuxkpi/common/src/linux_rcu.c
View file

@ -2,6 +2,10 @@
* Copyright (c) 2016 Matthew Macy (mmacy@mattmacy.io)
* Copyright (c) 2017-2021 Hans Petter Selasky (hselasky@freebsd.org)
* All rights reserved.
* Copyright (c) 2024 The FreeBSD Foundation
*
* Portions of this software were developed by Björn Zeeb
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@ -245,6 +249,33 @@ linux_rcu_read_unlock(unsigned type)
sched_unpin();
}
bool
linux_rcu_read_lock_held(unsigned type)
{
#ifdef INVARINATS
struct linux_epoch_record *record __diagused;
struct task_struct *ts;
MPASS(type < RCU_TYPE_MAX);
if (RCU_SKIP())
return (false);
if (__current_unallocated(curthread))
return (false);
ts = current;
if (ts->rcu_recurse[type] == 0)
return (false);
MPASS(curthread->td_pinned != 0);
MPASS((record = &DPCPU_GET(linux_epoch_record[type])) &&
record->epoch_record.active != 0);
#endif
return (true);
}
static void
linux_synchronize_rcu_cb(ck_epoch_t *epoch __unused, ck_epoch_record_t *epoch_record, void *arg __unused)
{