Bug #357833 Setting RLIMIT_DATA to zero breaks with linux 4.5+

We used to set the process datasize rlimit to zero to prevent
any internal use of brk() from having any effect. But later
linux kernels redefine RLIMIT_DATA as the size of any data
areas, including some dynamic mmap memory allocations.

See bug #357833 for the commit that went into linux 4.5
changing the definition of RLIMIT_DATA. So don't mess with
RLIMIT_DATA anymore. Just remember it for use in the syscall
wrappers.

This also cleans up some hacks around the execv and spawn wrappers.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15766

diff --git a/NEWS b/NEWS
index 16189e30d742071a47254ad95a16e63dc856a3b0..fff9f76ec6d55a0ef4cc1db21aeba704c8294aa8 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -58,6 +58,7 @@ where XXXXXX is the bug number as listed below.
 355454  do not intercept malloc related symbols from the runtime linker
 356044  Dwarf line info reader misinterprets is_stmt register
 356817  valgrind.h triggers compiler errors on MSVC when defining NVALGRIND
+357833  Setting RLIMIT_DATA to zero breaks with linux 4.5+
 357871  pthread_spin_destroy not properly wrapped
 357887  Fix a file handle leak. VG_(fclose) did not close the file
 358030  support direct socket calls on x86 32bit (new in linux 4.3)

diff --git a/coregrind/m_libcproc.c b/coregrind/m_libcproc.c
index f314b55eea88e286f8e65f5abf28f21916bf2c50..a30f7dc8f0c5071d6ba30a319bca3e7eac61dbef 100644 (file)
--- a/coregrind/m_libcproc.c
+++ b/coregrind/m_libcproc.c
@@ -450,9 +450,6 @@ void VG_(execv) ( const HChar* filename, const HChar** argv )
    HChar** envp;
    SysRes res;
 
-   /* restore the DATA rlimit for the child */
-   VG_(setrlimit)(VKI_RLIMIT_DATA, &VG_(client_rlimit_data));
-
    envp = VG_(env_clone)(VG_(client_envp));
    VG_(env_remove_valgrind_env_stuff)( envp, True /*ro_strings*/, NULL );
 
@@ -511,17 +508,9 @@ Int VG_(spawn) ( const HChar *filename, const HChar **argv )
 #  undef COPY_CHAR_TO_ARGENV
 #  undef COPY_STRING_TOARGENV
 
-   /* HACK: Temporarily restore the DATA rlimit for spawned child. */
-   VG_(setrlimit)(VKI_RLIMIT_DATA, &VG_(client_rlimit_data));
-
    SysRes res = VG_(do_syscall5)(__NR_spawn, (UWord) filename, (UWord) NULL, 0,
                                  (UWord) argenv, argenv_size);
 
-   /* Restore DATA rlimit back to its previous value set in m_main.c. */
-   struct vki_rlimit zero = { 0, 0 };
-   zero.rlim_max = VG_(client_rlimit_data).rlim_max;
-   VG_(setrlimit)(VKI_RLIMIT_DATA, &zero);
-
    VG_(free)(argenv);
    for (HChar **p = envp; *p != NULL; p++) {
       VG_(free)(*p);

diff --git a/coregrind/m_main.c b/coregrind/m_main.c
index 1821c9412fa7a7f2a12a7262cfb2663534c64d6d..9b659ae564b57e20b6cfe4f6c05b3b4326e0e1ae 100644 (file)
--- a/coregrind/m_main.c
+++ b/coregrind/m_main.c
@@ -1627,7 +1627,6 @@ Int valgrind_main ( Int argc, HChar **argv, HChar **envp )
    Bool    logging_to_fd      = False;
    const HChar* xml_fname_unexpanded = NULL;
    Int     loglevel, i;
-   struct vki_rlimit zero = { 0, 0 };
    XArray* addr2dihandle = NULL;
 
    //============================================================
@@ -1800,13 +1799,15 @@ Int valgrind_main ( Int argc, HChar **argv, HChar **envp )
    VG_(debugLog)(1, "main", "... %s\n", VG_(name_of_launcher));
 
    //--------------------------------------------------------------
-   // Get the current process datasize rlimit, and set it to zero.
-   // This prevents any internal uses of brk() from having any effect.
-   // We remember the old value so we can restore it on exec, so that
-   // child processes will have a reasonable brk value.
+   // We used to set the process datasize rlimit to zero to prevent
+   // any internal use of brk() from having any effect. But later
+   // linux kernels redefine RLIMIT_DATA as the size of any data
+   // areas, including some dynamic mmap memory allocations.
+   // See bug #357833 for the commit that went into linux 4.5
+   // changing the definition of RLIMIT_DATA. So don't mess with
+   // RLIMIT_DATA here now anymore. Just remember it for use in
+   // the syscall wrappers.
    VG_(getrlimit)(VKI_RLIMIT_DATA, &VG_(client_rlimit_data));
-   zero.rlim_max = VG_(client_rlimit_data).rlim_max;
-   VG_(setrlimit)(VKI_RLIMIT_DATA, &zero);
 
    // Get the current process stack rlimit.
    VG_(getrlimit)(VKI_RLIMIT_STACK, &VG_(client_rlimit_stack));

diff --git a/coregrind/m_syswrap/syswrap-generic.c b/coregrind/m_syswrap/syswrap-generic.c
index aa60d675218ef0ad8badcc287f528a01e7be7615..061c1e1436b8c2610ed045c04e622abfc524be8f 100644 (file)
--- a/coregrind/m_syswrap/syswrap-generic.c
+++ b/coregrind/m_syswrap/syswrap-generic.c
@@ -3014,9 +3014,6 @@ PRE(sys_execve)
       vg_assert(j == tot_args+1);
    }
 
-   /* restore the DATA rlimit for the child */
-   VG_(setrlimit)(VKI_RLIMIT_DATA, &VG_(client_rlimit_data));
-
    /*
       Set the signal state up for exec.
 

diff --git a/coregrind/m_syswrap/syswrap-solaris.c b/coregrind/m_syswrap/syswrap-solaris.c
index 175d0f65a7756450db319bd5e6872e3293cddbf0..44282164e5af5f8c1964ee163eed71f6eb20c3ab 100644 (file)
--- a/coregrind/m_syswrap/syswrap-solaris.c
+++ b/coregrind/m_syswrap/syswrap-solaris.c
@@ -1589,21 +1589,12 @@ PRE(sys_spawn)
 #undef COPY_CHAR_TO_ARGENV
 #undef COPY_STRING_TOARGENV
 
-   /* HACK: Temporarily restore the DATA rlimit for spawned child.
-      This is a terrible hack to provide sensible brk limit for child. */
-   VG_(setrlimit)(VKI_RLIMIT_DATA, &VG_(client_rlimit_data));
-
    /* Actual spawn() syscall. */
    SysRes res = VG_(do_syscall5)(__NR_spawn, (UWord) path, (UWord) attrs,
                                  attrs_size, (UWord) argenv, argenv_size);
    SET_STATUS_from_SysRes(res);
    VG_(free)(argenv);
 
-   /* Restore DATA rlimit back to its previous value set in m_main.c. */
-   struct vki_rlimit zero = { 0, 0 };
-   zero.rlim_max = VG_(client_rlimit_data).rlim_max;
-   VG_(setrlimit)(VKI_RLIMIT_DATA, &zero);
-
    if (SUCCESS) {
       PRINT("   spawn: process %d spawned child %ld\n", VG_(getpid)(), RES);
    }
@@ -3794,9 +3785,6 @@ PRE(sys_execve)
       VG_(sigprocmask)(VKI_SIG_SETMASK, &tst->sig_mask, NULL);
    }
 
-   /* Restore the DATA rlimit for the child. */
-   VG_(setrlimit)(VKI_RLIMIT_DATA, &VG_(client_rlimit_data));
-
    /* Debug-only printing. */
    if (0) {
       HChar **cpp;