/*
This file is part of drd, a thread error detector.
Copyright (C) 2006-2017 Bart Van Assche <bvanassche@acm.org>.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307, USA.
The GNU General Public License is contained in the file COPYING.
*/
#include "drd_clientobj.h"
#include "drd_error.h"
#include "drd_rwlock.h"
#include "pub_tool_vki.h"
#include "pub_tool_errormgr.h" // VG_(maybe_record_error)()
#include "pub_tool_libcassert.h" // tl_assert()
#include "pub_tool_libcprint.h" // VG_(message)()
#include "pub_tool_libcproc.h" // VG_(read_millisecond_timer)()
#include "pub_tool_machine.h" // VG_(get_IP)()
#include "pub_tool_mallocfree.h" // VG_(malloc)(), VG_(free)()
#include "pub_tool_threadstate.h" // VG_(get_running_tid)()
/* Local type definitions. */
struct rwlock_thread_info
{
UWord tid; // DrdThreadId.
UInt reader_nesting_count;
UInt writer_nesting_count;
// Segment of last unlock call by this thread that unlocked a writer lock.
Segment* latest_wrlocked_segment;
// Segment of last unlock call by this thread that unlocked a reader lock.
Segment* latest_rdlocked_segment;
};
/* Local functions. */
static void rwlock_cleanup(struct rwlock_info* p);
static void rwlock_delete_thread(struct rwlock_info* const p,
const DrdThreadId tid);
/* Local variables. */
static Bool DRD_(s_trace_rwlock);
static UInt DRD_(s_exclusive_threshold_ms);
static UInt DRD_(s_shared_threshold_ms);
static ULong DRD_(s_rwlock_segment_creation_count);
/* Function definitions. */
void DRD_(rwlock_set_trace)(const Bool trace_rwlock)
{
tl_assert(trace_rwlock == False || trace_rwlock == True);
DRD_(s_trace_rwlock) = trace_rwlock;
}
void DRD_(rwlock_set_exclusive_threshold)(const UInt exclusive_threshold_ms)
{
DRD_(s_exclusive_threshold_ms) = exclusive_threshold_ms;
}
void DRD_(rwlock_set_shared_threshold)(const UInt shared_threshold_ms)
{
DRD_(s_shared_threshold_ms) = shared_threshold_ms;
}
static Bool DRD_(rwlock_is_rdlocked)(struct rwlock_info* p)
{
struct rwlock_thread_info* q;
VG_(OSetGen_ResetIter)(p->thread_info);
for ( ; (q = VG_(OSetGen_Next)(p->thread_info)) != 0; )
{
return q->reader_nesting_count > 0;
}
return False;
}
static Bool DRD_(rwlock_is_wrlocked)(struct rwlock_info* p)
{
struct rwlock_thread_info* q;
VG_(OSetGen_ResetIter)(p->thread_info);
for ( ; (q = VG_(OSetGen_Next)(p->thread_info)) != 0; )
{
return q->writer_nesting_count > 0;
}
return False;
}
static Bool DRD_(rwlock_is_locked)(struct rwlock_info* p)
{
return DRD_(rwlock_is_rdlocked)(p) || DRD_(rwlock_is_wrlocked)(p);
}
static Bool DRD_(rwlock_is_rdlocked_by)(struct rwlock_info* p,
const DrdThreadId tid)
{
const UWord uword_tid = tid;
struct rwlock_thread_info* q;
q = VG_(OSetGen_Lookup)(p->thread_info, &uword_tid);
return q && q->reader_nesting_count > 0;
}
static Bool DRD_(rwlock_is_wrlocked_by)(struct rwlock_info* p,
const DrdThreadId tid)
{
const UWord uword_tid = tid;
struct rwlock_thread_info* q;
q = VG_(OSetGen_Lookup)(p->thread_info, &uword_tid);
return q && q->writer_nesting_count > 0;
}
static Bool DRD_(rwlock_is_locked_by)(struct rwlock_info* p,
const DrdThreadId tid)
{
return (DRD_(rwlock_is_rdlocked_by)(p, tid)
|| DRD_(rwlock_is_wrlocked_by)(p, tid));
}
/** Either look up or insert a node corresponding to DRD thread id 'tid'. */
static
struct rwlock_thread_info*
DRD_(lookup_or_insert_node)(OSet* oset, const UWord tid)
{
struct rwlock_thread_info* q;
q = VG_(OSetGen_Lookup)(oset, &tid);
if (q == 0)
{
q = VG_(OSetGen_AllocNode)(oset, sizeof(*q));
q->tid = tid;
q->reader_nesting_count = 0;
q->writer_nesting_count = 0;
q->latest_wrlocked_segment = 0;
q->latest_rdlocked_segment = 0;
VG_(OSetGen_Insert)(oset, q);
}
tl_assert(q);
return q;
}
/**
* Combine the vector clock corresponding to the last unlock operation of
* reader-writer lock p into the vector clock of thread 'tid'.
*/
static void DRD_(rwlock_combine_other_vc)(struct rwlock_info* const p,
const DrdThreadId tid,
const Bool readers_too)
{
struct rwlock_thread_info* q;
VectorClock old_vc;
DRD_(vc_copy)(&old_vc, DRD_(thread_get_vc)(tid));
VG_(OSetGen_ResetIter)(p->thread_info);
for ( ; (q = VG_(OSetGen_Next)(p->thread_info)) != 0; ) {
if (q->tid != tid) {
if (q->latest_wrlocked_segment)
DRD_(vc_combine)(DRD_(thread_get_vc)(tid),
&q->latest_wrlocked_segment->vc);
if (readers_too && q->latest_rdlocked_segment)
DRD_(vc_combine)(DRD_(thread_get_vc)(tid),
&q->latest_rdlocked_segment->vc);
}
}
DRD_(thread_update_conflict_set)(tid, &old_vc);
DRD_(vc_cleanup)(&old_vc);
}
/**
* Compare the type of the rwlock specified at initialization time with
* the type passed as an argument, and complain if these two types do not
* match.
*/
static Bool drd_rwlock_check_type(struct rwlock_info* const p,
const RwLockT rwlock_type)
{
tl_assert(p);
/* The code below has to be updated if additional rwlock types are added. */
tl_assert(rwlock_type == pthread_rwlock || rwlock_type == user_rwlock);
tl_assert(p->rwlock_type == pthread_rwlock || p->rwlock_type == user_rwlock);
if (p->rwlock_type == rwlock_type)
return True;
{
RwlockErrInfo REI = { DRD_(thread_get_running_tid)(), p->a1 };
VG_(maybe_record_error)
(VG_(get_running_tid)(),
RwlockErr,
VG_(get_IP)(VG_(get_running_tid)()),
rwlock_type == pthread_rwlock
? "Attempt to use a user-defined rwlock as a POSIX rwlock"
: "Attempt to use a POSIX rwlock as a user-defined rwlock",
&REI);
}
return False;
}
/** Initialize the rwlock_info data structure *p. */
static
void DRD_(rwlock_initialize)(struct rwlock_info* const p, const Addr rwlock,
const RwLockT rwlock_type)
{
tl_assert(rwlock != 0);
tl_assert(p->a1 == rwlock);
tl_assert(p->type == ClientRwlock);
p->cleanup = (void(*)(DrdClientobj*))rwlock_cleanup;
p->delete_thread
= (void(*)(DrdClientobj*, DrdThreadId))rwlock_delete_thread;
p->rwlock_type = rwlock_type;
p->thread_info = VG_(OSetGen_Create)(
0, 0, VG_(malloc), "drd.rwlock.ri.1", VG_(free));
p->acquiry_time_ms = 0;
p->acquired_at = 0;
}
/** Deallocate the memory that was allocated by rwlock_initialize(). */
static void rwlock_cleanup(struct rwlock_info* p)
{
struct rwlock_thread_info* q;
tl_assert(p);
if (DRD_(s_trace_rwlock))
DRD_(trace_msg)("[%u] rwlock_destroy 0x%lx",
DRD_(thread_get_running_tid)(), p->a1);
if (DRD_(rwlock_is_locked)(p))
{
RwlockErrInfo REI = { DRD_(thread_get_running_tid)(), p->a1 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
RwlockErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Destroying locked rwlock",
&REI);
}
VG_(OSetGen_ResetIter)(p->thread_info);
for ( ; (q = VG_(OSetGen_Next)(p->thread_info)) != 0; )
{
DRD_(sg_put)(q->latest_wrlocked_segment);
DRD_(sg_put)(q->latest_rdlocked_segment);
}
VG_(OSetGen_Destroy)(p->thread_info);
}
static
struct rwlock_info*
DRD_(rwlock_get_or_allocate)(const Addr rwlock, const RwLockT rwlock_type)
{
struct rwlock_info* p;
tl_assert(offsetof(DrdClientobj, rwlock) == 0);
p = &(DRD_(clientobj_get)(rwlock, ClientRwlock)->rwlock);
if (p)
{
drd_rwlock_check_type(p, rwlock_type);
return p;
}
if (DRD_(clientobj_present)(rwlock, rwlock + 1))
{
GenericErrInfo GEI = {
.tid = DRD_(thread_get_running_tid)(),
.addr = rwlock,
};
VG_(maybe_record_error)(VG_(get_running_tid)(),
GenericErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Not a reader-writer lock",
&GEI);
return 0;
}
p = &(DRD_(clientobj_add)(rwlock, ClientRwlock)->rwlock);
DRD_(rwlock_initialize)(p, rwlock, rwlock_type);
return p;
}
static struct rwlock_info* DRD_(rwlock_get)(const Addr rwlock)
{
tl_assert(offsetof(DrdClientobj, rwlock) == 0);
return &(DRD_(clientobj_get)(rwlock, ClientRwlock)->rwlock);
}
/** Called before pthread_rwlock_init(). */
struct rwlock_info* DRD_(rwlock_pre_init)(const Addr rwlock,
const RwLockT rwlock_type)
{
struct rwlock_info* p;
if (DRD_(s_trace_rwlock))
DRD_(trace_msg)("[%u] rwlock_init 0x%lx",
DRD_(thread_get_running_tid)(), rwlock);
p = DRD_(rwlock_get)(rwlock);
if (p)
drd_rwlock_check_type(p, rwlock_type);
if (p)
{
const ThreadId vg_tid = VG_(get_running_tid)();
RwlockErrInfo REI = { DRD_(thread_get_running_tid)(), p->a1 };
VG_(maybe_record_error)(vg_tid,
RwlockErr,
VG_(get_IP)(vg_tid),
"Reader-writer lock reinitialization",
&REI);
return p;
}
p = DRD_(rwlock_get_or_allocate)(rwlock, rwlock_type);
return p;
}
/** Called after pthread_rwlock_destroy(). */
void DRD_(rwlock_post_destroy)(const Addr rwlock, const RwLockT rwlock_type)
{
struct rwlock_info* p;
p = DRD_(rwlock_get)(rwlock);
if (p == 0)
{
GenericErrInfo GEI = {
.tid = DRD_(thread_get_running_tid)(),
.addr = rwlock,
};
VG_(maybe_record_error)(VG_(get_running_tid)(),
GenericErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Not a reader-writer lock",
&GEI);
return;
}
drd_rwlock_check_type(p, rwlock_type);
DRD_(clientobj_remove)(rwlock, ClientRwlock);
}
/**
* Called before pthread_rwlock_rdlock() is invoked. If a data structure for
* the client-side object was not yet created, do this now. Also check whether
* an attempt is made to lock recursively a synchronization object that must
* not be locked recursively.
*/
void DRD_(rwlock_pre_rdlock)(const Addr rwlock, const RwLockT rwlock_type)
{
struct rwlock_info* p;
if (DRD_(s_trace_rwlock))
DRD_(trace_msg)("[%u] pre_rwlock_rdlock 0x%lx",
DRD_(thread_get_running_tid)(), rwlock);
p = DRD_(rwlock_get_or_allocate)(rwlock, rwlock_type);
tl_assert(p);
if (DRD_(rwlock_is_wrlocked_by)(p, DRD_(thread_get_running_tid)())) {
RwlockErrInfo REI = { DRD_(thread_get_running_tid)(), p->a1 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
RwlockErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Already locked for writing by calling thread",
&REI);
}
}
/**
* Update rwlock_info state when locking the pthread_rwlock_t mutex.
* Note: this function must be called after pthread_rwlock_rdlock() has been
* called, or a race condition is triggered !
*/
void DRD_(rwlock_post_rdlock)(const Addr rwlock, const RwLockT rwlock_type,
const Bool took_lock)
{
const DrdThreadId drd_tid = DRD_(thread_get_running_tid)();
struct rwlock_info* p;
struct rwlock_thread_info* q;
if (DRD_(s_trace_rwlock))
DRD_(trace_msg)("[%u] post_rwlock_rdlock 0x%lx", drd_tid, rwlock);
p = DRD_(rwlock_get)(rwlock);
if (! p || ! took_lock)
return;
tl_assert(! DRD_(rwlock_is_wrlocked)(p));
q = DRD_(lookup_or_insert_node)(p->thread_info, drd_tid);
if (++q->reader_nesting_count == 1)
{
DRD_(thread_new_segment)(drd_tid);
DRD_(s_rwlock_segment_creation_count)++;
DRD_(rwlock_combine_other_vc)(p, drd_tid, False);
p->acquiry_time_ms = VG_(read_millisecond_timer)();
p->acquired_at = VG_(record_ExeContext)(VG_(get_running_tid)(), 0);
}
}
/**
* Called before pthread_rwlock_wrlock() is invoked. If a data structure for
* the client-side object was not yet created, do this now. Also check whether
* an attempt is made to lock recursively a synchronization object that must
* not be locked recursively.
*/
void DRD_(rwlock_pre_wrlock)(const Addr rwlock, const RwLockT rwlock_type)
{
struct rwlock_info* p;
p = DRD_(rwlock_get)(rwlock);
if (DRD_(s_trace_rwlock))
DRD_(trace_msg)("[%u] pre_rwlock_wrlock 0x%lx",
DRD_(thread_get_running_tid)(), rwlock);
if (p == 0)
p = DRD_(rwlock_get_or_allocate)(rwlock, rwlock_type);
tl_assert(p);
if (DRD_(rwlock_is_wrlocked_by)(p, DRD_(thread_get_running_tid)()))
{
RwlockErrInfo REI = { DRD_(thread_get_running_tid)(), p->a1 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
RwlockErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Recursive writer locking not allowed",
&REI);
}
}
/**
* Update rwlock_info state when locking the pthread_rwlock_t rwlock.
* Note: this function must be called after pthread_rwlock_wrlock() has
* finished, or a race condition is triggered !
*/
void DRD_(rwlock_post_wrlock)(const Addr rwlock, const RwLockT rwlock_type,
const Bool took_lock)
{
const DrdThreadId drd_tid = DRD_(thread_get_running_tid)();
struct rwlock_info* p;
struct rwlock_thread_info* q;
p = DRD_(rwlock_get)(rwlock);
if (DRD_(s_trace_rwlock))
DRD_(trace_msg)("[%u] post_rwlock_wrlock 0x%lx", drd_tid, rwlock);
if (! p || ! took_lock)
return;
q = DRD_(lookup_or_insert_node)(p->thread_info,
DRD_(thread_get_running_tid)());
tl_assert(q->writer_nesting_count == 0);
q->writer_nesting_count++;
tl_assert(q->writer_nesting_count == 1);
DRD_(thread_new_segment)(drd_tid);
DRD_(s_rwlock_segment_creation_count)++;
DRD_(rwlock_combine_other_vc)(p, drd_tid, True);
p->acquiry_time_ms = VG_(read_millisecond_timer)();
p->acquired_at = VG_(record_ExeContext)(VG_(get_running_tid)(), 0);
}
/**
* Update rwlock_info state when unlocking the pthread_rwlock_t rwlock.
*
* @param rwlock Pointer to pthread_rwlock_t data structure in the client space.
*
* @return New value of the rwlock recursion count.
*
* @note This function must be called before pthread_rwlock_unlock() is called,
* or a race condition is triggered !
*/
void DRD_(rwlock_pre_unlock)(const Addr rwlock, const RwLockT rwlock_type)
{
const DrdThreadId drd_tid = DRD_(thread_get_running_tid)();
const ThreadId vg_tid = VG_(get_running_tid)();
struct rwlock_info* p;
struct rwlock_thread_info* q;
if (DRD_(s_trace_rwlock))
DRD_(trace_msg)("[%u] rwlock_unlock 0x%lx", drd_tid, rwlock);
p = DRD_(rwlock_get)(rwlock);
if (p == 0)
{
GenericErrInfo GEI = {
.tid = DRD_(thread_get_running_tid)(),
.addr = rwlock,
};
VG_(maybe_record_error)(VG_(get_running_tid)(),
GenericErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Not a reader-writer lock",
&GEI);
return;
}
drd_rwlock_check_type(p, rwlock_type);
if (! DRD_(rwlock_is_locked_by)(p, drd_tid))
{
RwlockErrInfo REI = { DRD_(thread_get_running_tid)(), p->a1 };
VG_(maybe_record_error)(vg_tid,
RwlockErr,
VG_(get_IP)(vg_tid),
"Reader-writer lock not locked by calling thread",
&REI);
return;
}
q = DRD_(lookup_or_insert_node)(p->thread_info, drd_tid);
tl_assert(q);
if (q->reader_nesting_count > 0)
{
q->reader_nesting_count--;
if (q->reader_nesting_count == 0 && DRD_(s_shared_threshold_ms) > 0)
{
Long held = VG_(read_millisecond_timer)() - p->acquiry_time_ms;
if (held > DRD_(s_shared_threshold_ms))
{
HoldtimeErrInfo HEI
= { DRD_(thread_get_running_tid)(),
rwlock, p->acquired_at, held, DRD_(s_shared_threshold_ms) };
VG_(maybe_record_error)(vg_tid,
HoldtimeErr,
VG_(get_IP)(vg_tid),
"rwlock",
&HEI);
}
}
if (q->reader_nesting_count == 0 && q->writer_nesting_count == 0)
{
/*
* This pthread_rwlock_unlock() call really unlocks the rwlock. Save
* the current vector clock of the thread such that it is available
* when this rwlock is locked again.
*/
DRD_(thread_get_latest_segment)(&q->latest_rdlocked_segment, drd_tid);
DRD_(thread_new_segment)(drd_tid);
DRD_(s_rwlock_segment_creation_count)++;
}
}
else if (q->writer_nesting_count > 0)
{
q->writer_nesting_count--;
if (q->writer_nesting_count == 0 && DRD_(s_exclusive_threshold_ms) > 0)
{
Long held = VG_(read_millisecond_timer)() - p->acquiry_time_ms;
if (held > DRD_(s_exclusive_threshold_ms))
{
HoldtimeErrInfo HEI
= { DRD_(thread_get_running_tid)(),
rwlock, p->acquired_at, held,
DRD_(s_exclusive_threshold_ms) };
VG_(maybe_record_error)(vg_tid,
HoldtimeErr,
VG_(get_IP)(vg_tid),
"rwlock",
&HEI);
}
}
if (q->reader_nesting_count == 0 && q->writer_nesting_count == 0)
{
/*
* This pthread_rwlock_unlock() call really unlocks the rwlock. Save
* the current vector clock of the thread such that it is available
* when this rwlock is locked again.
*/
DRD_(thread_get_latest_segment)(&q->latest_wrlocked_segment, drd_tid);
DRD_(thread_new_segment)(drd_tid);
DRD_(s_rwlock_segment_creation_count)++;
}
}
else
{
tl_assert(False);
}
}
/** Called when thread tid stops to exist. */
static void rwlock_delete_thread(struct rwlock_info* const p,
const DrdThreadId tid)
{
struct rwlock_thread_info* q;
if (DRD_(rwlock_is_locked_by)(p, tid))
{
RwlockErrInfo REI = { DRD_(thread_get_running_tid)(), p->a1 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
RwlockErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Reader-writer lock still locked at thread exit",
&REI);
q = DRD_(lookup_or_insert_node)(p->thread_info, tid);
q->reader_nesting_count = 0;
q->writer_nesting_count = 0;
}
}
ULong DRD_(get_rwlock_segment_creation_count)(void)
{
return DRD_(s_rwlock_segment_creation_count);
}