http://sourceware.org/ml/gdb-patches/2009-10/msg00142.html Subject: [patch] Fix GNU/Linux core open: Can't read pathname for load map: Input/output error. Hi, GDB currently always prints on loading a core file: warning: Can't read pathname for load map: Input/output error. The patch is not nice but it was WONTFIXed on the glibc side in: http://sourceware.org/ml/libc-alpha/2009-10/msg00001.html The same message in GDB PR 8882 and glibc PR 387 was for ld-linux.so.2 l_name but that one is now ignored thanks to IGNORE_FIRST_LINK_MAP_ENTRY. This fix is intended for Linux system vDSO l_name which is a second entry in the DSO list. Regression tested on {x86_86,x86_64-m32,i686}-fedora11-linux-gnu. Thanks, Jan gdb/ 2009-10-06 Jan Kratochvil Do not print false warning on reading core file with vDSO on GNU/Linux. * solib-svr4.c (svr4_current_sos): Suppress the warning if MASTER_SO_LIST is still NULL. * solib.c (update_solib_list): New variable saved_so_list_head. Conditionally restart the function. [ Context backport. ] Index: gdb-7.3.50.20110722/gdb/solib-svr4.c =================================================================== --- gdb-7.3.50.20110722.orig/gdb/solib-svr4.c 2011-07-22 19:26:46.000000000 +0200 +++ gdb-7.3.50.20110722/gdb/solib-svr4.c 2011-07-22 19:29:36.000000000 +0200 @@ -1197,8 +1197,18 @@ svr4_current_sos (void) target_read_string (lm_name (new), &buffer, SO_NAME_MAX_PATH_SIZE - 1, &errcode); if (errcode != 0) - warning (_("Can't read pathname for load map: %s."), - safe_strerror (errcode)); + { + /* During the first ever DSO list reading some strings may be + unreadable as residing in the ld.so readonly memory not being + present in a dumped core file. Delay the error check after + the first pass of DSO list scanning when ld.so should be + already mapped in and all the DSO list l_name memory gets + readable. */ + + if (master_so_list () != NULL) + warning (_("Can't read pathname for load map: %s."), + safe_strerror (errcode)); + } else { struct build_id *build_id; Index: gdb-7.3.50.20110722/gdb/solib.c =================================================================== --- gdb-7.3.50.20110722.orig/gdb/solib.c 2011-06-30 21:29:54.000000000 +0200 +++ gdb-7.3.50.20110722/gdb/solib.c 2011-07-22 19:29:10.000000000 +0200 @@ -706,6 +706,7 @@ update_solib_list (int from_tty, struct struct target_so_ops *ops = solib_ops (target_gdbarch); struct so_list *inferior = ops->current_sos(); struct so_list *gdb, **gdb_link; + struct so_list *saved_so_list_head = so_list_head; /* We can reach here due to changing solib-search-path or the sysroot, before having any inferior. */ @@ -846,6 +847,12 @@ update_solib_list (int from_tty, struct observer_notify_solib_loaded (i); } + /* If this was the very first DSO list scan and we possibly read in ld.so + recheck all the formerly unreadable DSO names strings. */ + + if (saved_so_list_head == NULL && so_list_head != NULL) + return update_solib_list (from_tty, target); + /* If a library was not found, issue an appropriate warning message. We have to use a single call to warning in case the front end does something special with warnings, e.g., pop up