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[dwarf] Need to guard against multiple threads accessing the rs cache.

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Signed-off-by: Arun Sharma <arun.sharma@google.com>
This commit is contained in:
Arun Sharma 2006-07-26 21:44:38 -06:00 committed by David Mosberger-Tang
parent 8cdd8bfed8
commit 4312719cbc
1 changed files with 61 additions and 7 deletions
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68
src/dwarf/Gparser.c
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@ -472,10 +472,36 @@ flush_rs_cache (struct dwarf_rs_cache *cache)
cache->hash[i] = -1;
}
static struct dwarf_rs_cache *
get_rs_cache (unw_addr_space_t as)
static inline struct dwarf_rs_cache *
get_rs_cache (unw_addr_space_t as, intrmask_t *saved_maskp)
{
struct dwarf_rs_cache *cache = &as->global_cache;
unw_caching_policy_t caching = as->caching_policy;
if (caching == UNW_CACHE_NONE)
return NULL;
#ifdef HAVE_ATOMIC_H
if (!spin_trylock_irqsave (&cache->busy, *saved_maskp))
return NULL;
#else
# ifdef HAVE___THREAD
if (as->caching_policy == UNW_CACHE_PER_THREAD)
cache = &dwarf_per_thread_cache;
# endif
# ifdef HAVE_ATOMIC_OPS_H
if (AO_test_and_set (&cache->busy) == AO_TS_SET)
return NULL;
# else
sigprocmask (SIG_SETMASK, &unwi_full_mask, saved_maskp);
if (likely (caching == UNW_CACHE_GLOBAL))
{
Debug (16, "%s: acquiring lock\n", __FUNCTION__);
mutex_lock (&cache->lock);
}
# endif
#endif
if (atomic_read (&as->cache_generation) != atomic_read (&cache->generation))
{
flush_rs_cache (cache);
@ -485,6 +511,26 @@ get_rs_cache (unw_addr_space_t as)
return cache;
}
static inline void
put_rs_cache (unw_addr_space_t as, struct dwarf_rs_cache *cache,
intrmask_t *saved_maskp)
{
assert (as->caching_policy != UNW_CACHE_NONE);
Debug (16, "unmasking signals/interrupts and releasing lock\n");
#ifdef HAVE_ATOMIC_H
spin_unlock_irqrestore (&cache->busy, *saved_maskp);
#else
# ifdef HAVE_ATOMIC_OPS_H
AO_CLEAR (&cache->busy);
# else
if (likely (as->caching_policy == UNW_CACHE_GLOBAL))
mutex_unlock (&cache->lock);
sigprocmask (SIG_SETMASK, saved_maskp, NULL);
# endif
#endif
}
static inline unw_hash_index_t
hash (unw_word_t ip)
{
@ -763,12 +809,15 @@ dwarf_find_save_locs (struct dwarf_cursor *c)
dwarf_state_record_t sr;
dwarf_reg_state_t *rs, *rs1;
struct dwarf_rs_cache *cache;
int ret;
int ret = 0;
intrmask_t saved_mask;
if (c->as->caching_policy == UNW_CACHE_NONE)
return uncached_dwarf_find_save_locs (c);
cache = get_rs_cache(c->as);
cache = get_rs_cache(c->as, &saved_mask);
if (!cache)
return -UNW_ENOINFO; /* cache is busy */
rs = rs_lookup(cache, c);
if (rs)
@ -778,10 +827,10 @@ dwarf_find_save_locs (struct dwarf_cursor *c)
}
if ((ret = fetch_proc_info (c, c->ip, 1)) < 0)
return ret;
goto out;
if ((ret = create_state_record_for (c, &sr, c->ip)) < 0)
return ret;
goto out;
rs1 = &sr.rs_current;
if (rs1)
@ -792,7 +841,7 @@ dwarf_find_save_locs (struct dwarf_cursor *c)
{
dprintf ("%s: failed to create unwind rs\n", __FUNCTION__);
ret = -UNW_EUNSPEC;
return ret;
goto out;
}
}
cache->buckets[c->prev_rs].hint = rs - cache->buckets;
@ -802,7 +851,12 @@ dwarf_find_save_locs (struct dwarf_cursor *c)
put_unwind_info (c, &c->pi);
out:
put_rs_cache (c->as, cache, &saved_mask);
return ret;
apply:
put_rs_cache (c->as, cache, &saved_mask);
if ((ret = apply_reg_state (c, rs)) < 0)
return ret;