Fix lock handling in memory hander of nscd.

The commit 20e498bd 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.

diff --git a/ChangeLog b/ChangeLog
index a81c5b4..37f20a4 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+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
@@ -5,6 +15,7 @@
        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
index 524c0a6..8dac48e 100644 (file)
--- a/nscd/aicache.c
+++ b/nscd/aicache.c
@@ -543,8 +543,6 @@ next_nip:
       (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
index 184d538..fc20084 100644 (file)
--- 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
index 51e2273..77ffcdf 100644 (file)
--- 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
index c33aaf3..f8d4742 100644 (file)
--- 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
index fcea6db..80ea951 100644 (file)
--- 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
index 2338e7e..fc5b44e 100644 (file)
--- 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
index dc98d30..c965c97 100644 (file)
--- 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);
        }
     }