UCM: gate brk/sbrk hooks on configure-time availability (#11198)

Some platforms do not provide brk()/sbrk(). UCM currently builds and registers
hooks for these symbols unconditionally, which can break the build or lead to
undefined behavior when the functions are absent.

Author: GenericRikka

AUTHORS

@@ -91,6 +91,7 @@ Peter Rudenko <peterr@mellanox.com>
 Peter-Jan Gootzen <pgootzen@nvidia.com>
 Qiang Yu <Qiang.Yu@amd.com>
 Raul Akhmetshin <rakhmetshin@nvidia.com>
+Rikka Göring <rikka.goering@outlook.de>
 Robert Dietrich <rdietrich@nvidia.com>
 Rohit Zambre <rzambre@uci.edu>
 Roie Danino <rdanino@nvidia.com>

config/m4/ucm.m4

@@ -8,6 +8,8 @@
 #
 # Memory allocator selection
 #
+AC_CHECK_FUNCS([brk sbrk])
+
 AC_ARG_WITH([allocator],
     [AS_HELP_STRING([--with-allocator=NAME],
         [Build UCX with predefined memory allocator. The supported values are:
@@ -18,13 +20,18 @@ AC_ARG_WITH([allocator],
 case ${with_allocator} in
     ptmalloc286)
         AC_MSG_NOTICE(Memory allocator is ptmalloc-2.8.6 version)
-        AC_DEFINE([HAVE_UCM_PTMALLOC286], 1, [Use ptmalloc-2.8.6 version])
+        AC_DEFINE([HAVE_UCM_PTMALLOC286], [1], [Use ptmalloc-2.8.6 version])
         HAVE_UCM_PTMALLOC286=yes
+        AS_IF([test "x$ac_cv_func_sbrk" != xyes], [
+            AC_DEFINE([HAVE_MORECORE], [0],
+                      [Disable MORECORE in ptmalloc (no sbrk available)])
+        ])
         ;;
     *)
         AC_MSG_ERROR(Cannot continue. Unsupported memory allocator name
                      in --with-allocator=[$with_allocator])
         ;;
+
 esac
 
 AM_CONDITIONAL([HAVE_UCM_PTMALLOC286],[test "x$HAVE_UCM_PTMALLOC286" = "xyes"])

src/ucm/malloc/malloc_hook.c

@@ -836,11 +836,29 @@ ucs_status_t ucm_malloc_install(int events)
 #endif
     }
 
+#if !HAVE_BRK
+    if (events & UCM_EVENT_BRK) {
+        ucm_debug("brk event requested, but brk() is not available");
+        events &= ~UCM_EVENT_BRK;
+    }
+#endif
+
+#if !HAVE_SBRK
+    if (events & UCM_EVENT_SBRK) {
+        ucm_debug("sbrk event requested, but sbrk() is not available");
+        events &= ~UCM_EVENT_SBRK;
+    }
+#endif
+
+#if HAVE_SBRK
     if (!(ucm_malloc_hook_state.install_state & UCM_MALLOC_INSTALLED_SBRK_EVH)) {
         ucm_debug("installing malloc-sbrk event handler");
         ucm_event_handler_add(&sbrk_handler);
         ucm_malloc_hook_state.install_state |= UCM_MALLOC_INSTALLED_SBRK_EVH;
     }
+#else
+    (void)sbrk_handler;
+#endif
 
     /* When running on valgrind, don't even try malloc hooks.
      * We want to release original blocks to silence the leak check, so we must

src/ucm/mmap/install.c

@@ -86,8 +86,12 @@ static ucm_mmap_func_t ucm_mmap_funcs[] = {
 #endif
     { UCM_MMAP_RELOC_ENTRY(shmat),   UCM_EVENT_SHMAT,   UCM_EVENT_NONE},
     { UCM_MMAP_RELOC_ENTRY(shmdt),   UCM_EVENT_SHMDT,   UCM_EVENT_SHMAT},
+#if HAVE_SBRK
     { UCM_MMAP_RELOC_ENTRY(sbrk),    UCM_EVENT_SBRK,    UCM_EVENT_NONE},
+#endif
+#if HAVE_BRK
     { UCM_MMAP_RELOC_ENTRY(brk),     UCM_EVENT_BRK,     UCM_EVENT_NONE},
+#endif
     { UCM_MMAP_RELOC_ENTRY(madvise), UCM_EVENT_MADVISE, UCM_EVENT_NONE},
     { {NULL, NULL, NULL}, UCM_EVENT_NONE}
 };
@@ -138,10 +142,12 @@ static void ucm_mmap_event_test_callback(ucm_event_type_t event_type,
 /* Call brk() and check return value, to avoid compile error of unused result */
 static void ucm_brk_checked(void *addr)
 {
+#if HAVE_BRK
     int ret = brk(addr);
     if ((ret != 0) && (addr != NULL)) {
         ucm_diag("brk(addr=%p) failed: %m", addr);
     }
+#endif
 }
 
 /* Fire events with pre/post action. The problem is in call sequence: we
@@ -199,6 +205,7 @@ ucm_fire_mmap_events_internal(int events, ucm_mmap_test_events_data_t *data,
     }
 
     if (exclusive && !RUNNING_ON_VALGRIND) {
+#if HAVE_SBRK
         sbrk_size = ucm_get_page_size();
         if (events & (UCM_EVENT_BRK|UCM_EVENT_VM_MAPPED|UCM_EVENT_VM_UNMAPPED)) {
             p = ucm_get_current_brk();
@@ -213,6 +220,7 @@ ucm_fire_mmap_events_internal(int events, ucm_mmap_test_events_data_t *data,
             UCM_FIRE_EVENT(events, UCM_EVENT_SBRK|UCM_EVENT_VM_UNMAPPED,
                            data, (void)sbrk(-sbrk_size));
         }
+#endif
     } else {
         /* To avoid side effects on other threads and valgrind heap corruption,
          * pass invalid parameters. We assume that if the natives events are

src/ucm/util/replace.c

@@ -55,8 +55,12 @@ UCM_DEFINE_REPLACE_FUNC(mremap, void*, MAP_FAILED, void*, size_t, size_t, int,
 #endif
 UCM_DEFINE_REPLACE_FUNC(shmat,   void*, MAP_FAILED, int, const void*, int)
 UCM_DEFINE_REPLACE_FUNC(shmdt,   int,   -1,         const void*)
+#if HAVE_SBRK
 UCM_DEFINE_REPLACE_FUNC(sbrk,    void*, MAP_FAILED, intptr_t)
+#endif
+#if HAVE_BRK
 UCM_DEFINE_REPLACE_FUNC(brk,     int,   -1,         void*)
+#endif
 UCM_DEFINE_REPLACE_FUNC(madvise, int,   -1,         void*, size_t, int)
 
 UCM_DEFINE_SELECT_FUNC(mmap, void*, SYS_mmap, void*, size_t, int, int, int,
@@ -122,7 +126,9 @@ int ucm_orig_shmdt(const void *shmaddr)
 
 #endif
 
+#if HAVE_BRK
 _UCM_DEFINE_DLSYM_FUNC(brk, ucm_orig_dlsym_brk, ucm_override_brk, int, void*)
+#endif
 
 int ucm_orig_brk(void *addr)
 {
@@ -141,8 +147,10 @@ int ucm_orig_brk(void *addr)
     }
 }
 
+#if HAVE_SBRK
 _UCM_DEFINE_DLSYM_FUNC(sbrk, ucm_orig_dlsym_sbrk, ucm_override_sbrk, void*,
                        intptr_t)
+#endif
 
 void *ucm_orig_sbrk(intptr_t increment)
 {

src/ucm/util/sys.c

@@ -377,10 +377,16 @@ char *ucm_concat_path(char *buffer, size_t max, const char *dir, const char *fil
 
 void *ucm_brk_syscall(void *addr)
 {
+#if HAVE_DECL_SYS_BRK
     /* Return type is equivalent to full pointer size */
     UCS_STATIC_ASSERT(sizeof(syscall(0)) == sizeof(void*));
 
     return (void*)syscall(SYS_brk, addr);
+#else
+    (void)addr;
+    errno = ENOSYS;
+    return NULL;
+#endif
 }
 
 pid_t ucm_get_tid()