ac77d0c37 ("pack-objects: shrink size field in struct object_entry",
2018-04-14) added an extra usage of read_lock/read_unlock in the newly
introduced oe_get_size_slow for thread safety in parallel calls to
try_delta(). Unfortunately oe_get_size_slow is also used in serial
code, some of which is called before the first invocation of
ll_find_deltas. As such the read mutex is not guaranteed to be
initialized.
Resolve this by moving the read mutex to packing_data and initializing
it in prepare_packing_data which is initialized in cmd_pack_objects.
Signed-off-by: Patrick Hogg <phogg@xxxxxxxxxxxx>
---
builtin/pack-objects.c | 7 ++-----
pack-objects.c | 1 +
pack-objects.h | 10 ++++++++++
3 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 411aefd68..506061b4c 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1954,9 +1954,8 @@ static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
}
/* Protect access to object database */
-static pthread_mutex_t read_mutex;
-#define read_lock() pthread_mutex_lock(&read_mutex)
-#define read_unlock() pthread_mutex_unlock(&read_mutex)
+#define read_lock() packing_data_read_lock(&to_pack)
+#define read_unlock() packing_data_read_unlock(&to_pack)
/* Protect delta_cache_size */
static pthread_mutex_t cache_mutex;
@@ -2381,7 +2380,6 @@ static pthread_cond_t progress_cond;
*/
static void init_threaded_search(void)
{
- init_recursive_mutex(&read_mutex);
pthread_mutex_init(&cache_mutex, NULL);
pthread_mutex_init(&progress_mutex, NULL);
pthread_cond_init(&progress_cond, NULL);
@@ -2392,7 +2390,6 @@ static void cleanup_threaded_search(void)
{
set_try_to_free_routine(old_try_to_free_routine);
pthread_cond_destroy(&progress_cond);
- pthread_mutex_destroy(&read_mutex);
pthread_mutex_destroy(&cache_mutex);
pthread_mutex_destroy(&progress_mutex);
}
diff --git a/pack-objects.c b/pack-objects.c
index b6cdbb016..3554c43ac 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -150,6 +150,7 @@ void prepare_packing_data(struct packing_data *pdata)
1UL << OE_DELTA_SIZE_BITS);
#ifndef NO_PTHREADS
pthread_mutex_init(&pdata->lock, NULL);
+ init_recursive_mutex(&pdata->read_lock);
#endif
}
diff --git a/pack-objects.h b/pack-objects.h
index dc869f26c..0a038e3bc 100644
--- a/pack-objects.h
+++ b/pack-objects.h
@@ -146,6 +146,7 @@ struct packing_data {
struct packed_git **in_pack;
pthread_mutex_t lock;
+ pthread_mutex_t read_lock;
/*
* This list contains entries for bases which we know the other side
@@ -174,6 +175,15 @@ static inline void packing_data_unlock(struct packing_data *pdata)
pthread_mutex_unlock(&pdata->lock);
}
+static inline void packing_data_read_lock(struct packing_data *pdata)
+{
+ pthread_mutex_lock(&pdata->read_lock);
+}
+static inline void packing_data_read_unlock(struct packing_data *pdata)
+{
+ pthread_mutex_unlock(&pdata->read_lock);
+}
+
struct object_entry *packlist_alloc(struct packing_data *pdata,
const unsigned char *sha1,
uint32_t index_pos);
--
2.20.1.windows.1
