commit 5876f5032f60c45c4bd19e7ea7d0c14d0346b93e Author: Jan Kratochvil Date: Wed May 21 16:25:53 2014 +0200 Fix TLS access for -static -pthread I have posted: TLS variables access for -static -lpthread executables https://sourceware.org/ml/libc-help/2014-03/msg00024.html and the GDB patch below has been confirmed as OK for current glibcs. Further work should be done for newer glibcs: Improve TLS variables glibc compatibility https://sourceware.org/bugzilla/show_bug.cgi?id=16954 Still the patch below implements the feature in a fully functional way backward compatible with current glibcs, it depends on the following glibc source line: csu/libc-tls.c main_map->l_tls_modid = 1; gdb/ 2014-05-21 Jan Kratochvil Fix TLS access for -static -pthread. * linux-thread-db.c (struct thread_db_info): Add td_thr_tlsbase_p. (try_thread_db_load_1): Initialize it. (thread_db_get_thread_local_address): Call it if LM is zero. * target.c (target_translate_tls_address): Remove LM_ADDR zero check. * target.h (struct target_ops) (to_get_thread_local_address): Add load_module_addr comment. gdb/gdbserver/ 2014-05-21 Jan Kratochvil Fix TLS access for -static -pthread. * gdbserver/thread-db.c (struct thread_db): Add td_thr_tlsbase_p. (thread_db_get_tls_address): Call it if LOAD_MODULE is zero. (thread_db_load_search, try_thread_db_load_1): Initialize it. gdb/testsuite/ 2014-05-21 Jan Kratochvil Fix TLS access for -static -pthread. * gdb.threads/staticthreads.c (tlsvar): New. (thread_function, main): Initialize it. * gdb.threads/staticthreads.exp: Try gdb_compile_pthreads for $have_tls. Add clean_restart. <$have_tls != "">: Check TLSVAR. Message-ID: <20140410115204.GB16411@host2.jankratochvil.net> Index: gdb-7.6.1/gdb/gdbserver/thread-db.c =================================================================== --- gdb-7.6.1.orig/gdb/gdbserver/thread-db.c +++ gdb-7.6.1/gdb/gdbserver/thread-db.c @@ -88,6 +88,9 @@ struct thread_db td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th, psaddr_t map_address, size_t offset, psaddr_t *address); + td_err_e (*td_thr_tlsbase_p) (const td_thrhandle_t *th, + unsigned long int modid, + psaddr_t *base); const char ** (*td_symbol_list_p) (void); }; @@ -497,7 +500,10 @@ thread_db_get_tls_address (struct thread if (thread_db == NULL || !thread_db->all_symbols_looked_up) return TD_ERR; - if (thread_db->td_thr_tls_get_addr_p == NULL) + /* If td_thr_tls_get_addr is missing rather do not expect td_thr_tlsbase + could work. */ + if (thread_db->td_thr_tls_get_addr_p == NULL + || (load_module == 0 && thread_db->td_thr_tlsbase_p == NULL)) return -1; lwp = get_thread_lwp (thread); @@ -508,12 +514,28 @@ thread_db_get_tls_address (struct thread saved_inferior = current_inferior; current_inferior = thread; - /* Note the cast through uintptr_t: this interface only works if - a target address fits in a psaddr_t, which is a host pointer. - So a 32-bit debugger can not access 64-bit TLS through this. */ - err = thread_db->td_thr_tls_get_addr_p (&lwp->th, - (psaddr_t) (uintptr_t) load_module, - offset, &addr); + + if (load_module != 0) + { + /* Note the cast through uintptr_t: this interface only works if + a target address fits in a psaddr_t, which is a host pointer. + So a 32-bit debugger can not access 64-bit TLS through this. */ + err = thread_db->td_thr_tls_get_addr_p (&lwp->th, + (psaddr_t) (uintptr_t) load_module, + offset, &addr); + } + else + { + /* This code path handles the case of -static -pthread executables: + https://sourceware.org/ml/libc-help/2014-03/msg00024.html + For older GNU libc r_debug.r_map is NULL. For GNU libc after + PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL. + The constant number 1 depends on GNU __libc_setup_tls + initialization of l_tls_modid to 1. */ + err = thread_db->td_thr_tlsbase_p (&lwp->th, 1, &addr); + addr = (char *) addr + offset; + } + current_inferior = saved_inferior; if (err == TD_OK) { @@ -565,6 +587,7 @@ thread_db_load_search (void) tdb->td_ta_set_event_p = &td_ta_set_event; tdb->td_ta_event_getmsg_p = &td_ta_event_getmsg; tdb->td_thr_tls_get_addr_p = &td_thr_tls_get_addr; + tdb->td_thr_tlsbase_p = &td_thr_tlsbase; return 1; } @@ -633,6 +656,7 @@ try_thread_db_load_1 (void *handle) CHK (0, tdb->td_ta_set_event_p = dlsym (handle, "td_ta_set_event")); CHK (0, tdb->td_ta_event_getmsg_p = dlsym (handle, "td_ta_event_getmsg")); CHK (0, tdb->td_thr_tls_get_addr_p = dlsym (handle, "td_thr_tls_get_addr")); + CHK (0, tdb->td_thr_tlsbase_p = dlsym (handle, "td_thr_tlsbase")); #undef CHK Index: gdb-7.6.1/gdb/linux-thread-db.c =================================================================== --- gdb-7.6.1.orig/gdb/linux-thread-db.c +++ gdb-7.6.1/gdb/linux-thread-db.c @@ -196,6 +196,9 @@ struct thread_db_info td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th, psaddr_t map_address, size_t offset, psaddr_t *address); + td_err_e (*td_thr_tlsbase_p) (const td_thrhandle_t *th, + unsigned long int modid, + psaddr_t *base); }; /* List of known processes using thread_db, and the required @@ -797,6 +800,7 @@ try_thread_db_load_1 (struct thread_db_i info->td_ta_event_getmsg_p = dlsym (info->handle, "td_ta_event_getmsg"); info->td_thr_event_enable_p = dlsym (info->handle, "td_thr_event_enable"); info->td_thr_tls_get_addr_p = dlsym (info->handle, "td_thr_tls_get_addr"); + info->td_thr_tlsbase_p = dlsym (info->handle, "td_thr_tlsbase"); if (thread_db_find_new_threads_silently (inferior_ptid) != 0) { @@ -1798,21 +1802,39 @@ thread_db_get_thread_local_address (stru info = get_thread_db_info (GET_PID (ptid)); - /* glibc doesn't provide the needed interface. */ - if (!info->td_thr_tls_get_addr_p) - throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR, - _("No TLS library support")); - - /* Caller should have verified that lm != 0. */ - gdb_assert (lm != 0); - /* Finally, get the address of the variable. */ - /* Note the cast through uintptr_t: this interface only works if - a target address fits in a psaddr_t, which is a host pointer. - So a 32-bit debugger can not access 64-bit TLS through this. */ - err = info->td_thr_tls_get_addr_p (&thread_info->private->th, - (psaddr_t)(uintptr_t) lm, - offset, &address); + if (lm != 0) + { + /* glibc doesn't provide the needed interface. */ + if (!info->td_thr_tls_get_addr_p) + throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR, + _("No TLS library support")); + + /* Note the cast through uintptr_t: this interface only works if + a target address fits in a psaddr_t, which is a host pointer. + So a 32-bit debugger can not access 64-bit TLS through this. */ + err = info->td_thr_tls_get_addr_p (&thread_info->private->th, + (psaddr_t)(uintptr_t) lm, + offset, &address); + } + else + { + /* If glibc doesn't provide the needed interface throw an error + that LM is zero - normally cases it should not be. */ + if (!info->td_thr_tlsbase_p) + throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR, + _("TLS load module not found")); + + /* This code path handles the case of -static -pthread executables: + https://sourceware.org/ml/libc-help/2014-03/msg00024.html + For older GNU libc r_debug.r_map is NULL. For GNU libc after + PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL. + The constant number 1 depends on GNU __libc_setup_tls + initialization of l_tls_modid to 1. */ + err = info->td_thr_tlsbase_p (&thread_info->private->th, + 1, &address); + address = (char *) address + offset; + } #ifdef THREAD_DB_HAS_TD_NOTALLOC /* The memory hasn't been allocated, yet. */ Index: gdb-7.6.1/gdb/target.c =================================================================== --- gdb-7.6.1.orig/gdb/target.c +++ gdb-7.6.1/gdb/target.c @@ -1165,10 +1165,6 @@ target_translate_tls_address (struct obj /* Fetch the load module address for this objfile. */ lm_addr = gdbarch_fetch_tls_load_module_address (target_gdbarch (), objfile); - /* If it's 0, throw the appropriate exception. */ - if (lm_addr == 0) - throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR, - _("TLS load module not found")); addr = target->to_get_thread_local_address (target, ptid, lm_addr, offset); Index: gdb-7.6.1/gdb/target.h =================================================================== --- gdb-7.6.1.orig/gdb/target.h +++ gdb-7.6.1/gdb/target.h @@ -557,7 +557,8 @@ struct target_ops thread-local storage for the thread PTID and the shared library or executable file given by OBJFILE. If that block of thread-local storage hasn't been allocated yet, this function - may return an error. */ + may return an error. LOAD_MODULE_ADDR may be zero for statically + linked multithreaded inferiors. */ CORE_ADDR (*to_get_thread_local_address) (struct target_ops *ops, ptid_t ptid, CORE_ADDR load_module_addr, Index: gdb-7.6.1/gdb/testsuite/gdb.threads/staticthreads.c =================================================================== --- gdb-7.6.1.orig/gdb/testsuite/gdb.threads/staticthreads.c +++ gdb-7.6.1/gdb/testsuite/gdb.threads/staticthreads.c @@ -28,10 +28,17 @@ sem_t semaphore; +#ifdef HAVE_TLS +__thread int tlsvar; +#endif + void * thread_function (void *arg) { - printf ("Thread executing\n"); +#ifdef HAVE_TLS + tlsvar = 2; +#endif + printf ("Thread executing\n"); /* tlsvar-is-set */ while (sem_wait (&semaphore) != 0) { if (errno != EINTR) @@ -57,6 +64,9 @@ main (int argc, char **argv) return -1; } +#ifdef HAVE_TLS + tlsvar = 1; +#endif /* Create a thread, wait for it to complete. */ { Index: gdb-7.6.1/gdb/testsuite/gdb.threads/staticthreads.exp =================================================================== --- gdb-7.6.1.orig/gdb/testsuite/gdb.threads/staticthreads.exp +++ gdb-7.6.1/gdb/testsuite/gdb.threads/staticthreads.exp @@ -22,11 +22,16 @@ standard_testfile set static_flag "-static" -if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" \ - executable \ - [list debug "additional_flags=${static_flag}" \ - ]] != "" } { - return -1 +foreach have_tls { "-DHAVE_TLS" "" } { + if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" \ + executable \ + [list debug "additional_flags=${static_flag} ${have_tls}" \ + ]] == "" } { + break + } + if { $have_tls == "" } { + return -1 + } } clean_restart ${binfile} @@ -96,3 +101,18 @@ gdb_test_multiple "quit" "$test" { pass "$test" } } +clean_restart ${binfile} + + +if { "$have_tls" != "" } { + if ![runto_main] { + return -1 + } + gdb_breakpoint [gdb_get_line_number "tlsvar-is-set"] + gdb_continue_to_breakpoint "tlsvar-is-set" ".* tlsvar-is-set .*" + gdb_test "p tlsvar" " = 2" "tlsvar in thread" + gdb_test "thread 1" ".*" + # Unwind from pthread_join. + gdb_test "up 10" " in main .*" + gdb_test "p tlsvar" " = 1" "tlsvar in main" +}