| Message ID | 20230109224954.161672-5-cota@braap.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | tsan fixes | expand |
Emilio Cota <cota@braap.org> writes: > Fixes this tsan crash, easy to reproduce with any large enough program: > > $ tests/unit/test-qht > 1..2 > ThreadSanitizer: CHECK failed: sanitizer_deadlock_detector.h:67 "((n_all_locks_)) < (((sizeof(all_locks_with_contexts_)/sizeof((all_locks_with_contexts_)[0]))))" (0x40, 0x40) (tid=1821568) > #0 __tsan::CheckUnwind() ../../../../src/libsanitizer/tsan/tsan_rtl.cpp:353 (libtsan.so.2+0x90034) > #1 __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) ../../../../src/libsanitizer/sanitizer_common/sanitizer_termination.cpp:86 (libtsan.so.2+0xca555) > #2 __sanitizer::DeadlockDetectorTLS<__sanitizer::TwoLevelBitVector<1ul, __sanitizer::BasicBitVector<unsigned long> > >::addLock(unsigned long, unsigned long, unsigned int) ../../../../src/libsanitizer/sanitizer_common/sanitizer_deadlock_detector.h:67 (libtsan.so.2+0xb3616) > #3 __sanitizer::DeadlockDetectorTLS<__sanitizer::TwoLevelBitVector<1ul, __sanitizer::BasicBitVector<unsigned long> > >::addLock(unsigned long, unsigned long, unsigned int) ../../../../src/libsanitizer/sanitizer_common/sanitizer_deadlock_detector.h:59 (libtsan.so.2+0xb3616) > #4 __sanitizer::DeadlockDetector<__sanitizer::TwoLevelBitVector<1ul, __sanitizer::BasicBitVector<unsigned long> > >::onLockAfter(__sanitizer::DeadlockDetectorTLS<__sanitizer::TwoLevelBitVector<1ul, __sanitizer::BasicBitVector<unsigned long> > >*, unsigned long, unsigned int) ../../../../src/libsanitizer/sanitizer_common/sanitizer_deadlock_detector.h:216 (libtsan.so.2+0xb3616) > #5 __sanitizer::DD::MutexAfterLock(__sanitizer::DDCallback*, __sanitizer::DDMutex*, bool, bool) ../../../../src/libsanitizer/sanitizer_common/sanitizer_deadlock_detector1.cpp:169 (libtsan.so.2+0xb3616) > #6 __tsan::MutexPostLock(__tsan::ThreadState*, unsigned long, unsigned long, unsigned int, int) ../../../../src/libsanitizer/tsan/tsan_rtl_mutex.cpp:200 (libtsan.so.2+0xa3382) > #7 __tsan_mutex_post_lock ../../../../src/libsanitizer/tsan/tsan_interface_ann.cpp:384 (libtsan.so.2+0x76bc3) > #8 qemu_spin_lock /home/cota/src/qemu/include/qemu/thread.h:259 (test-qht+0x44a97) > #9 qht_map_lock_buckets ../util/qht.c:253 (test-qht+0x44a97) > #10 do_qht_iter ../util/qht.c:809 (test-qht+0x45f33) > #11 qht_iter ../util/qht.c:821 (test-qht+0x45f33) > #12 iter_check ../tests/unit/test-qht.c:121 (test-qht+0xe473) > #13 qht_do_test ../tests/unit/test-qht.c:202 (test-qht+0xe473) > #14 qht_test ../tests/unit/test-qht.c:240 (test-qht+0xe7c1) > #15 test_default ../tests/unit/test-qht.c:246 (test-qht+0xe828) > #16 <null> <null> (libglib-2.0.so.0+0x7daed) > #17 <null> <null> (libglib-2.0.so.0+0x7d80a) > #18 <null> <null> (libglib-2.0.so.0+0x7d80a) > #19 g_test_run_suite <null> (libglib-2.0.so.0+0x7dfe9) > #20 g_test_run <null> (libglib-2.0.so.0+0x7e055) > #21 main ../tests/unit/test-qht.c:259 (test-qht+0xd2c6) > #22 __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 (libc.so.6+0x29d8f) > #23 __libc_start_main_impl ../csu/libc-start.c:392 (libc.so.6+0x29e3f) > #24 _start <null> (test-qht+0xdb44) > > Signed-off-by: Emilio Cota <cota@braap.org> > --- > util/qht.c | 101 +++++++++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 87 insertions(+), 14 deletions(-) > > diff --git a/util/qht.c b/util/qht.c > index 15866299e6..70cc733d5d 100644 > --- a/util/qht.c > +++ b/util/qht.c > @@ -151,6 +151,22 @@ struct qht_bucket { > > QEMU_BUILD_BUG_ON(sizeof(struct qht_bucket) > QHT_BUCKET_ALIGN); > > +/* > + * Under TSAN, we use striped locks instead of one lock per bucket chain. > + * This avoids crashing under TSAN, since TSAN aborts the program if more than > + * 64 locks are held (this is a hardcoded limit in TSAN). > + * When resizing a QHT we grab all the buckets' locks, which can easily > + * go over TSAN's limit. By using striped locks, we avoid this problem. > + * > + * Note: this number must be a power of two for easy index computation. > + */ > +#define QHT_TSAN_BUCKET_LOCKS_BITS 4 > +#define QHT_TSAN_BUCKET_LOCKS (1 << QHT_TSAN_BUCKET_LOCKS_BITS) > + > +struct qht_tsan_lock { > + QemuSpin lock; > +} QEMU_ALIGNED(QHT_BUCKET_ALIGN); > + > /** > * struct qht_map - structure to track an array of buckets > * @rcu: used by RCU. Keep it as the top field in the struct to help valgrind > @@ -160,6 +176,7 @@ QEMU_BUILD_BUG_ON(sizeof(struct qht_bucket) > QHT_BUCKET_ALIGN); > * @n_added_buckets: number of added (i.e. "non-head") buckets > * @n_added_buckets_threshold: threshold to trigger an upward resize once the > * number of added buckets surpasses it. > + * @tsan_bucket_locks: Array of striped locks to be used only under TSAN. > * > * Buckets are tracked in what we call a "map", i.e. this structure. > */ > @@ -169,6 +186,9 @@ struct qht_map { > size_t n_buckets; > size_t n_added_buckets; > size_t n_added_buckets_threshold; > +#ifdef CONFIG_TSAN > + struct qht_tsan_lock tsan_bucket_locks[QHT_TSAN_BUCKET_LOCKS]; > +#endif > }; > > /* trigger a resize when n_added_buckets > n_buckets / div */ > @@ -229,10 +249,62 @@ static inline size_t qht_elems_to_buckets(size_t n_elems) > return pow2ceil(n_elems / QHT_BUCKET_ENTRIES); > } > > -static inline void qht_head_init(struct qht_bucket *b) > +/* > + * When using striped locks (i.e. under TSAN), we have to be careful not > + * to operate on the same lock twice (e.g. when iterating through all buckets). > + * We achieve this by operating only on each stripe's first matching lock. > + */ > +static inline void qht_do_if_first_in_stripe(const struct qht_map *map, > + struct qht_bucket *b, > + void (*func)(QemuSpin *spin)) > +{ > +#ifdef CONFIG_TSAN > + unsigned long bucket_idx = b - map->buckets; > + bool is_first_in_stripe = (bucket_idx >> QHT_TSAN_BUCKET_LOCKS_BITS) == 0; > + if (is_first_in_stripe) { > + unsigned long lock_idx = bucket_idx & (QHT_TSAN_BUCKET_LOCKS - 1); > + func(&map->tsan_bucket_locks[lock_idx]); Hmm I ran into an issue with: ../util/qht.c:286:10: error: incompatible pointer types passing 'const struct qht_tsan_lock *' to parameter of type 'QemuSpin *' (aka 'struct QemuSpin *') [-Werror,-Wincompatible-pointer-types] func(&map->tsan_bucket_locks[lock_idx]); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ But changing the line to: func(&map->tsan_bucket_locks[lock_idx].lock); still fails because: ../../util/qht.c:266:14: error: passing 'const QemuSpin *' (aka 'const struct QemuSpin *') to parameter of type 'QemuSpin *' (aka 'struct QemuSpin *') discards qualifiers [\ -Werror,-Wincompatible-pointer-types-discards-qualifiers] func(&map->tsan_bucket_locks[lock_idx].lock); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > + } > +#else > + func(&b->lock); > +#endif > +} > + > +static inline void qht_bucket_lock_destroy(const struct qht_map *map, > + struct qht_bucket *b) > +{ > + qht_do_if_first_in_stripe(map, b, qemu_spin_destroy); > +} Who is meant to be calling this? > + > +static inline void qht_bucket_lock_do(const struct qht_map *map, > + struct qht_bucket *b, > + void (*func)(QemuSpin *lock)) > +{ > +#ifdef CONFIG_TSAN > + unsigned long bucket_idx = b - map->buckets; > + unsigned long lock_idx = bucket_idx & (QHT_TSAN_BUCKET_LOCKS - 1); > + func(&map->tsan_bucket_locks[lock_idx]); > +#else > + func(&b->lock); > +#endif > +} > + > +static inline void qht_bucket_lock(const struct qht_map *map, > + struct qht_bucket *b) > +{ > + qht_bucket_lock_do(map, b, qemu_spin_lock); > +} > + > +static inline void qht_bucket_unlock(const struct qht_map *map, > + struct qht_bucket *b) > +{ > + qht_bucket_lock_do(map, b, qemu_spin_unlock); > +} > + > +static inline void qht_head_init(struct qht_map *map, struct qht_bucket *b) > { > memset(b, 0, sizeof(*b)); > - qemu_spin_init(&b->lock); > + qht_do_if_first_in_stripe(map, b, qemu_spin_init); > seqlock_init(&b->sequence); > } > > @@ -250,7 +322,7 @@ static void qht_map_lock_buckets(struct qht_map *map) > for (i = 0; i < map->n_buckets; i++) { > struct qht_bucket *b = &map->buckets[i]; > > - qemu_spin_lock(&b->lock); > + qht_do_if_first_in_stripe(map, b, qemu_spin_lock); > } > } > > @@ -261,7 +333,7 @@ static void qht_map_unlock_buckets(struct qht_map *map) > for (i = 0; i < map->n_buckets; i++) { > struct qht_bucket *b = &map->buckets[i]; > > - qemu_spin_unlock(&b->lock); > + qht_do_if_first_in_stripe(map, b, qemu_spin_unlock); > } > } > > @@ -308,7 +380,7 @@ void qht_map_lock_buckets__no_stale(struct qht *ht, struct qht_map **pmap) > * Get a head bucket and lock it, making sure its parent map is not stale. > * @pmap is filled with a pointer to the bucket's parent map. > * > - * Unlock with qemu_spin_unlock(&b->lock). > + * Unlock with qht_bucket_unlock. > * > * Note: callers cannot have ht->lock held. > */ > @@ -322,18 +394,18 @@ struct qht_bucket *qht_bucket_lock__no_stale(struct qht *ht, uint32_t hash, > map = qatomic_rcu_read(&ht->map); > b = qht_map_to_bucket(map, hash); > > - qemu_spin_lock(&b->lock); > + qht_bucket_lock(map, b); > if (likely(!qht_map_is_stale__locked(ht, map))) { > *pmap = map; > return b; > } > - qemu_spin_unlock(&b->lock); > + qht_bucket_unlock(map, b); > > /* we raced with a resize; acquire ht->lock to see the updated ht->map */ > qht_lock(ht); > map = ht->map; > b = qht_map_to_bucket(map, hash); > - qemu_spin_lock(&b->lock); > + qht_bucket_lock(map, b); > qht_unlock(ht); > *pmap = map; > return b; > @@ -345,12 +417,13 @@ static inline bool qht_map_needs_resize(const struct qht_map *map) > map->n_added_buckets_threshold; > } > > -static inline void qht_chain_destroy(const struct qht_bucket *head) > +static inline void qht_chain_destroy(const struct qht_map *map, > + struct qht_bucket *head) > { > struct qht_bucket *curr = head->next; > struct qht_bucket *prev; > > - qemu_spin_destroy(&head->lock); > + qht_do_if_first_in_stripe(map, head, qemu_spin_destroy); > while (curr) { > prev = curr; > curr = curr->next; > @@ -364,7 +437,7 @@ static void qht_map_destroy(struct qht_map *map) > size_t i; > > for (i = 0; i < map->n_buckets; i++) { > - qht_chain_destroy(&map->buckets[i]); > + qht_chain_destroy(map, &map->buckets[i]); > } > qemu_vfree(map->buckets); > g_free(map); > @@ -390,7 +463,7 @@ static struct qht_map *qht_map_create(size_t n_buckets) > map->buckets = qemu_memalign(QHT_BUCKET_ALIGN, > sizeof(*map->buckets) * n_buckets); > for (i = 0; i < n_buckets; i++) { > - qht_head_init(&map->buckets[i]); > + qht_head_init(map, &map->buckets[i]); > } > return map; > } > @@ -638,7 +711,7 @@ bool qht_insert(struct qht *ht, void *p, uint32_t hash, void **existing) > b = qht_bucket_lock__no_stale(ht, hash, &map); > prev = qht_insert__locked(ht, map, b, p, hash, &needs_resize); > qht_bucket_debug__locked(b); > - qemu_spin_unlock(&b->lock); > + qht_bucket_unlock(map, b); > > if (unlikely(needs_resize) && ht->mode & QHT_MODE_AUTO_RESIZE) { > qht_grow_maybe(ht); > @@ -749,7 +822,7 @@ bool qht_remove(struct qht *ht, const void *p, uint32_t hash) > b = qht_bucket_lock__no_stale(ht, hash, &map); > ret = qht_remove__locked(b, p, hash); > qht_bucket_debug__locked(b); > - qemu_spin_unlock(&b->lock); > + qht_bucket_unlock(map, b); > return ret; > }
On Tue, Jan 10, 2023 at 20:58:01 +0000, Alex Bennée wrote: > Emilio Cota <cota@braap.org> writes: (snip) > > +static inline void qht_do_if_first_in_stripe(const struct qht_map *map, > > + struct qht_bucket *b, > > + void (*func)(QemuSpin *spin)) > > +{ > > +#ifdef CONFIG_TSAN > > + unsigned long bucket_idx = b - map->buckets; > > + bool is_first_in_stripe = (bucket_idx >> QHT_TSAN_BUCKET_LOCKS_BITS) == 0; > > + if (is_first_in_stripe) { > > + unsigned long lock_idx = bucket_idx & (QHT_TSAN_BUCKET_LOCKS - 1); > > + func(&map->tsan_bucket_locks[lock_idx]); > > Hmm I ran into an issue with: > > ../util/qht.c:286:10: error: incompatible pointer types passing 'const struct qht_tsan_lock *' to parameter of type 'QemuSpin *' (aka 'struct QemuSpin *') [-Werror,-Wincompatible-pointer-types] Gaah, sorry. I didn't notice this because of unrelated noise due to having to configure with --disable-werror. Fixed now by removing a bunch of const's and also using .lock. > > +static inline void qht_bucket_lock_destroy(const struct qht_map *map, > > + struct qht_bucket *b) > > +{ > > + qht_do_if_first_in_stripe(map, b, qemu_spin_destroy); > > +} > > Who is meant to be calling this? Should have been removed in v2; fixed now. I've uploaded the v3 series to https://github.com/cota/qemu/tree/tsan-v3 Please let me know if you want me to also mail it to the list. Thanks, Emilio
Emilio Cota <cota@braap.org> writes: > On Tue, Jan 10, 2023 at 20:58:01 +0000, Alex Bennée wrote: >> Emilio Cota <cota@braap.org> writes: > (snip) >> > +static inline void qht_do_if_first_in_stripe(const struct qht_map *map, >> > + struct qht_bucket *b, >> > + void (*func)(QemuSpin *spin)) >> > +{ >> > +#ifdef CONFIG_TSAN >> > + unsigned long bucket_idx = b - map->buckets; >> > + bool is_first_in_stripe = (bucket_idx >> QHT_TSAN_BUCKET_LOCKS_BITS) == 0; >> > + if (is_first_in_stripe) { >> > + unsigned long lock_idx = bucket_idx & (QHT_TSAN_BUCKET_LOCKS - 1); >> > + func(&map->tsan_bucket_locks[lock_idx]); >> >> Hmm I ran into an issue with: >> >> ../util/qht.c:286:10: error: incompatible pointer types passing >> 'const struct qht_tsan_lock *' to parameter of type 'QemuSpin *' >> (aka 'struct QemuSpin *') [-Werror,-Wincompatible-pointer-types] > > Gaah, sorry. I didn't notice this because of unrelated noise due > to having to configure with --disable-werror. Fixed now by removing > a bunch of const's and also using .lock. > >> > +static inline void qht_bucket_lock_destroy(const struct qht_map *map, >> > + struct qht_bucket *b) >> > +{ >> > + qht_do_if_first_in_stripe(map, b, qemu_spin_destroy); >> > +} >> >> Who is meant to be calling this? > > Should have been removed in v2; fixed now. > > I've uploaded the v3 series to https://github.com/cota/qemu/tree/tsan-v3 > > Please let me know if you want me to also mail it to the list. Please do and then I can be sure I'm upto date when I rebuild the PR. > Thanks, > > Emilio
diff --git a/util/qht.c b/util/qht.c index 15866299e6..70cc733d5d 100644 --- a/util/qht.c +++ b/util/qht.c @@ -151,6 +151,22 @@ struct qht_bucket { QEMU_BUILD_BUG_ON(sizeof(struct qht_bucket) > QHT_BUCKET_ALIGN); +/* + * Under TSAN, we use striped locks instead of one lock per bucket chain. + * This avoids crashing under TSAN, since TSAN aborts the program if more than + * 64 locks are held (this is a hardcoded limit in TSAN). + * When resizing a QHT we grab all the buckets' locks, which can easily + * go over TSAN's limit. By using striped locks, we avoid this problem. + * + * Note: this number must be a power of two for easy index computation. + */ +#define QHT_TSAN_BUCKET_LOCKS_BITS 4 +#define QHT_TSAN_BUCKET_LOCKS (1 << QHT_TSAN_BUCKET_LOCKS_BITS) + +struct qht_tsan_lock { + QemuSpin lock; +} QEMU_ALIGNED(QHT_BUCKET_ALIGN); + /** * struct qht_map - structure to track an array of buckets * @rcu: used by RCU. Keep it as the top field in the struct to help valgrind @@ -160,6 +176,7 @@ QEMU_BUILD_BUG_ON(sizeof(struct qht_bucket) > QHT_BUCKET_ALIGN); * @n_added_buckets: number of added (i.e. "non-head") buckets * @n_added_buckets_threshold: threshold to trigger an upward resize once the * number of added buckets surpasses it. + * @tsan_bucket_locks: Array of striped locks to be used only under TSAN. * * Buckets are tracked in what we call a "map", i.e. this structure. */ @@ -169,6 +186,9 @@ struct qht_map { size_t n_buckets; size_t n_added_buckets; size_t n_added_buckets_threshold; +#ifdef CONFIG_TSAN + struct qht_tsan_lock tsan_bucket_locks[QHT_TSAN_BUCKET_LOCKS]; +#endif }; /* trigger a resize when n_added_buckets > n_buckets / div */ @@ -229,10 +249,62 @@ static inline size_t qht_elems_to_buckets(size_t n_elems) return pow2ceil(n_elems / QHT_BUCKET_ENTRIES); } -static inline void qht_head_init(struct qht_bucket *b) +/* + * When using striped locks (i.e. under TSAN), we have to be careful not + * to operate on the same lock twice (e.g. when iterating through all buckets). + * We achieve this by operating only on each stripe's first matching lock. + */ +static inline void qht_do_if_first_in_stripe(const struct qht_map *map, + struct qht_bucket *b, + void (*func)(QemuSpin *spin)) +{ +#ifdef CONFIG_TSAN + unsigned long bucket_idx = b - map->buckets; + bool is_first_in_stripe = (bucket_idx >> QHT_TSAN_BUCKET_LOCKS_BITS) == 0; + if (is_first_in_stripe) { + unsigned long lock_idx = bucket_idx & (QHT_TSAN_BUCKET_LOCKS - 1); + func(&map->tsan_bucket_locks[lock_idx]); + } +#else + func(&b->lock); +#endif +} + +static inline void qht_bucket_lock_destroy(const struct qht_map *map, + struct qht_bucket *b) +{ + qht_do_if_first_in_stripe(map, b, qemu_spin_destroy); +} + +static inline void qht_bucket_lock_do(const struct qht_map *map, + struct qht_bucket *b, + void (*func)(QemuSpin *lock)) +{ +#ifdef CONFIG_TSAN + unsigned long bucket_idx = b - map->buckets; + unsigned long lock_idx = bucket_idx & (QHT_TSAN_BUCKET_LOCKS - 1); + func(&map->tsan_bucket_locks[lock_idx]); +#else + func(&b->lock); +#endif +} + +static inline void qht_bucket_lock(const struct qht_map *map, + struct qht_bucket *b) +{ + qht_bucket_lock_do(map, b, qemu_spin_lock); +} + +static inline void qht_bucket_unlock(const struct qht_map *map, + struct qht_bucket *b) +{ + qht_bucket_lock_do(map, b, qemu_spin_unlock); +} + +static inline void qht_head_init(struct qht_map *map, struct qht_bucket *b) { memset(b, 0, sizeof(*b)); - qemu_spin_init(&b->lock); + qht_do_if_first_in_stripe(map, b, qemu_spin_init); seqlock_init(&b->sequence); } @@ -250,7 +322,7 @@ static void qht_map_lock_buckets(struct qht_map *map) for (i = 0; i < map->n_buckets; i++) { struct qht_bucket *b = &map->buckets[i]; - qemu_spin_lock(&b->lock); + qht_do_if_first_in_stripe(map, b, qemu_spin_lock); } } @@ -261,7 +333,7 @@ static void qht_map_unlock_buckets(struct qht_map *map) for (i = 0; i < map->n_buckets; i++) { struct qht_bucket *b = &map->buckets[i]; - qemu_spin_unlock(&b->lock); + qht_do_if_first_in_stripe(map, b, qemu_spin_unlock); } } @@ -308,7 +380,7 @@ void qht_map_lock_buckets__no_stale(struct qht *ht, struct qht_map **pmap) * Get a head bucket and lock it, making sure its parent map is not stale. * @pmap is filled with a pointer to the bucket's parent map. * - * Unlock with qemu_spin_unlock(&b->lock). + * Unlock with qht_bucket_unlock. * * Note: callers cannot have ht->lock held. */ @@ -322,18 +394,18 @@ struct qht_bucket *qht_bucket_lock__no_stale(struct qht *ht, uint32_t hash, map = qatomic_rcu_read(&ht->map); b = qht_map_to_bucket(map, hash); - qemu_spin_lock(&b->lock); + qht_bucket_lock(map, b); if (likely(!qht_map_is_stale__locked(ht, map))) { *pmap = map; return b; } - qemu_spin_unlock(&b->lock); + qht_bucket_unlock(map, b); /* we raced with a resize; acquire ht->lock to see the updated ht->map */ qht_lock(ht); map = ht->map; b = qht_map_to_bucket(map, hash); - qemu_spin_lock(&b->lock); + qht_bucket_lock(map, b); qht_unlock(ht); *pmap = map; return b; @@ -345,12 +417,13 @@ static inline bool qht_map_needs_resize(const struct qht_map *map) map->n_added_buckets_threshold; } -static inline void qht_chain_destroy(const struct qht_bucket *head) +static inline void qht_chain_destroy(const struct qht_map *map, + struct qht_bucket *head) { struct qht_bucket *curr = head->next; struct qht_bucket *prev; - qemu_spin_destroy(&head->lock); + qht_do_if_first_in_stripe(map, head, qemu_spin_destroy); while (curr) { prev = curr; curr = curr->next; @@ -364,7 +437,7 @@ static void qht_map_destroy(struct qht_map *map) size_t i; for (i = 0; i < map->n_buckets; i++) { - qht_chain_destroy(&map->buckets[i]); + qht_chain_destroy(map, &map->buckets[i]); } qemu_vfree(map->buckets); g_free(map); @@ -390,7 +463,7 @@ static struct qht_map *qht_map_create(size_t n_buckets) map->buckets = qemu_memalign(QHT_BUCKET_ALIGN, sizeof(*map->buckets) * n_buckets); for (i = 0; i < n_buckets; i++) { - qht_head_init(&map->buckets[i]); + qht_head_init(map, &map->buckets[i]); } return map; } @@ -638,7 +711,7 @@ bool qht_insert(struct qht *ht, void *p, uint32_t hash, void **existing) b = qht_bucket_lock__no_stale(ht, hash, &map); prev = qht_insert__locked(ht, map, b, p, hash, &needs_resize); qht_bucket_debug__locked(b); - qemu_spin_unlock(&b->lock); + qht_bucket_unlock(map, b); if (unlikely(needs_resize) && ht->mode & QHT_MODE_AUTO_RESIZE) { qht_grow_maybe(ht); @@ -749,7 +822,7 @@ bool qht_remove(struct qht *ht, const void *p, uint32_t hash) b = qht_bucket_lock__no_stale(ht, hash, &map); ret = qht_remove__locked(b, p, hash); qht_bucket_debug__locked(b); - qemu_spin_unlock(&b->lock); + qht_bucket_unlock(map, b); return ret; }
Fixes this tsan crash, easy to reproduce with any large enough program: $ tests/unit/test-qht 1..2 ThreadSanitizer: CHECK failed: sanitizer_deadlock_detector.h:67 "((n_all_locks_)) < (((sizeof(all_locks_with_contexts_)/sizeof((all_locks_with_contexts_)[0]))))" (0x40, 0x40) (tid=1821568) #0 __tsan::CheckUnwind() ../../../../src/libsanitizer/tsan/tsan_rtl.cpp:353 (libtsan.so.2+0x90034) #1 __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) ../../../../src/libsanitizer/sanitizer_common/sanitizer_termination.cpp:86 (libtsan.so.2+0xca555) #2 __sanitizer::DeadlockDetectorTLS<__sanitizer::TwoLevelBitVector<1ul, __sanitizer::BasicBitVector<unsigned long> > >::addLock(unsigned long, unsigned long, unsigned int) ../../../../src/libsanitizer/sanitizer_common/sanitizer_deadlock_detector.h:67 (libtsan.so.2+0xb3616) #3 __sanitizer::DeadlockDetectorTLS<__sanitizer::TwoLevelBitVector<1ul, __sanitizer::BasicBitVector<unsigned long> > >::addLock(unsigned long, unsigned long, unsigned int) ../../../../src/libsanitizer/sanitizer_common/sanitizer_deadlock_detector.h:59 (libtsan.so.2+0xb3616) #4 __sanitizer::DeadlockDetector<__sanitizer::TwoLevelBitVector<1ul, __sanitizer::BasicBitVector<unsigned long> > >::onLockAfter(__sanitizer::DeadlockDetectorTLS<__sanitizer::TwoLevelBitVector<1ul, __sanitizer::BasicBitVector<unsigned long> > >*, unsigned long, unsigned int) ../../../../src/libsanitizer/sanitizer_common/sanitizer_deadlock_detector.h:216 (libtsan.so.2+0xb3616) #5 __sanitizer::DD::MutexAfterLock(__sanitizer::DDCallback*, __sanitizer::DDMutex*, bool, bool) ../../../../src/libsanitizer/sanitizer_common/sanitizer_deadlock_detector1.cpp:169 (libtsan.so.2+0xb3616) #6 __tsan::MutexPostLock(__tsan::ThreadState*, unsigned long, unsigned long, unsigned int, int) ../../../../src/libsanitizer/tsan/tsan_rtl_mutex.cpp:200 (libtsan.so.2+0xa3382) #7 __tsan_mutex_post_lock ../../../../src/libsanitizer/tsan/tsan_interface_ann.cpp:384 (libtsan.so.2+0x76bc3) #8 qemu_spin_lock /home/cota/src/qemu/include/qemu/thread.h:259 (test-qht+0x44a97) #9 qht_map_lock_buckets ../util/qht.c:253 (test-qht+0x44a97) #10 do_qht_iter ../util/qht.c:809 (test-qht+0x45f33) #11 qht_iter ../util/qht.c:821 (test-qht+0x45f33) #12 iter_check ../tests/unit/test-qht.c:121 (test-qht+0xe473) #13 qht_do_test ../tests/unit/test-qht.c:202 (test-qht+0xe473) #14 qht_test ../tests/unit/test-qht.c:240 (test-qht+0xe7c1) #15 test_default ../tests/unit/test-qht.c:246 (test-qht+0xe828) #16 <null> <null> (libglib-2.0.so.0+0x7daed) #17 <null> <null> (libglib-2.0.so.0+0x7d80a) #18 <null> <null> (libglib-2.0.so.0+0x7d80a) #19 g_test_run_suite <null> (libglib-2.0.so.0+0x7dfe9) #20 g_test_run <null> (libglib-2.0.so.0+0x7e055) #21 main ../tests/unit/test-qht.c:259 (test-qht+0xd2c6) #22 __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 (libc.so.6+0x29d8f) #23 __libc_start_main_impl ../csu/libc-start.c:392 (libc.so.6+0x29e3f) #24 _start <null> (test-qht+0xdb44) Signed-off-by: Emilio Cota <cota@braap.org> --- util/qht.c | 101 +++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 87 insertions(+), 14 deletions(-)