Fix lock handling in memory hander of nscd.

The commit 20e498b removes the pthread_mutex_rdlock() calls, but not the corresponding pthread_mutex_unlock() calls. Also, the database lock is never unlocked in one branch of the mempool_alloc() if. I think unreproducible random assert(dh->usable) crashes in prune_cache() were caused by this. But an easy way to make nscd threads hang with the broken locking was.
git-mirror · Jul 16, 2009 · 137028b · 137028b
1 parent 50158f9
commit 137028b
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Showing 8 changed files with 16 additions and 27 deletions.
diff --git a/ChangeLog b/ChangeLog
@@ -1,10 +1,21 @@
+2009-07-16  Petr Baudis  <pasky@suse.cz>
+
+	* nscd/mem.c (mempool_alloc): Fix unlock missing in the else branch.
+	* nscd/aicache.c: Remove bogus db->lock unlock.
+	* nscd/grpcache.c: Likewise.
+	* nscd/hstcache.c: Likewise.
+	* nscd/initgrcache.c: Likewise.
+	* nscd/pwdcache.c: Likewise.
+	* nscd/servicescache.c: Likewise.
+
 2009-07-16  Ulrich Drepper  <drepper@redhat.com>
 
 	* nscd/cache.c (cache_add): Use atomic_compare_and_exchange_bool_rel
 	instead of atomic_compare_and_exchange_bool_acq to ensure pointer
 	is written before the list head update.
 	Patch by Andreas Schwab <aschwab@redhat.com>.
 
+2009-07-16  Ulrich Drepper  <drepper@redhat.com>
 	    Jakub Jelinek  <jakub@redhat.com>
 
 	* malloc/malloc.c [ATOMIC_FASTBINS] (_int_free): Make check for

diff --git a/nscd/aicache.c b/nscd/aicache.c
@@ -543,8 +543,6 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req,
       (void) cache_add (req->type, key_copy, req->key_len, &dataset->head,
 			true, db, uid, he == NULL);
 
-      pthread_rwlock_unlock (&db->lock);
-
       /* Mark the old entry as obsolete.  */
       if (dh != NULL)
 	dh->usable = false;

diff --git a/nscd/grpcache.c b/nscd/grpcache.c
@@ -146,8 +146,6 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
 	      (void) cache_add (req->type, &dataset->strdata, req->key_len,
 				&dataset->head, true, db, owner, he == NULL);
 
-	      pthread_rwlock_unlock (&db->lock);
-
 	      /* Mark the old entry as obsolete.  */
 	      if (dh != NULL)
 		dh->usable = false;
@@ -367,12 +365,10 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
 		(void) cache_add (GETGRBYGID, cp, key_offset, &dataset->head,
 				  false, db, owner, false);
 	    }
-
-	out:
-	  pthread_rwlock_unlock (&db->lock);
 	}
     }
 
+out:
   if (__builtin_expect (written != total, 0) && debug_level > 0)
     {
       char buf[256];

diff --git a/nscd/hstcache.c b/nscd/hstcache.c
@@ -153,8 +153,6 @@ cache_addhst (struct database_dyn *db, int fd, request_header *req,
 	      (void) cache_add (req->type, &dataset->strdata, req->key_len,
 				&dataset->head, true, db, owner, he == NULL);
 
-	      pthread_rwlock_unlock (&db->lock);
-
 	      /* Mark the old entry as obsolete.  */
 	      if (dh != NULL)
 		dh->usable = false;
@@ -404,8 +402,6 @@ cache_addhst (struct database_dyn *db, int fd, request_header *req,
 
 	  (void) cache_add (req->type, key_copy, req->key_len,
 			    &dataset->head, true, db, owner, he == NULL);
-
-	  pthread_rwlock_unlock (&db->lock);
 	}
     }
 

diff --git a/nscd/initgrcache.c b/nscd/initgrcache.c
@@ -230,8 +230,6 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
 	      (void) cache_add (req->type, key_copy, req->key_len,
 				&dataset->head, true, db, uid, he == NULL);
 
-	      pthread_rwlock_unlock (&db->lock);
-
 	      /* Mark the old entry as obsolete.  */
 	      if (dh != NULL)
 		dh->usable = false;
@@ -388,8 +386,6 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
 
 	  (void) cache_add (INITGROUPS, cp, req->key_len, &dataset->head, true,
 			    db, uid, he == NULL);
-
-	  pthread_rwlock_unlock (&db->lock);
 	}
     }
 

diff --git a/nscd/mem.c b/nscd/mem.c
@@ -566,9 +566,6 @@ mempool_alloc (struct database_dyn *db, size_t len, int data_alloc)
 	    }
 	}
 
-      if (data_alloc)
-	pthread_rwlock_unlock (&db->lock);
-
       if (! db->last_alloc_failed)
 	{
 	  dbg_log (_("no more memory for database '%s'"), dbnames[db - dbs]);
@@ -591,5 +588,8 @@ mempool_alloc (struct database_dyn *db, size_t len, int data_alloc)
 
   pthread_mutex_unlock (&db->memlock);
 
+  if (data_alloc)
+    pthread_rwlock_unlock (&db->lock);
+
   return res;
 }
diff --git a/nscd/pwdcache.c b/nscd/pwdcache.c
@@ -153,8 +153,6 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
 	      (void) cache_add (req->type, key_copy, req->key_len,
 				&dataset->head, true, db, owner, he == NULL);
 
-	      pthread_rwlock_unlock (&db->lock);
-
 	      /* Mark the old entry as obsolete.  */
 	      if (dh != NULL)
 		dh->usable = false;
@@ -362,12 +360,10 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
 		(void) cache_add (GETPWBYUID, cp, key_offset, &dataset->head,
 				  false, db, owner, false);
 	    }
-
-	out:
-	  pthread_rwlock_unlock (&db->lock);
 	}
     }
 
+out:
   if (__builtin_expect (written != total, 0) && debug_level > 0)
     {
       char buf[256];

diff --git a/nscd/servicescache.c b/nscd/servicescache.c
@@ -136,8 +136,6 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
 	      (void) cache_add (req->type, &dataset->strdata, req->key_len,
 				&dataset->head, true, db, owner, he == NULL);
 
-	      pthread_rwlock_unlock (&db->lock);
-
 	      /* Mark the old entry as obsolete.  */
 	      if (dh != NULL)
 		dh->usable = false;
@@ -317,8 +315,6 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
 
 	  (void) cache_add (req->type, key_copy, req->key_len,
 			    &dataset->head, true, db, owner, he == NULL);
-
-	  pthread_rwlock_unlock (&db->lock);
 	}
     }