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Fix TLS access for -static -pthread (BZ 1080660).

This commit is contained in:
Jan Kratochvil 2014-05-05 22:40:04 +02:00
parent 331a1f1adc
commit 7f2a1f7d83
3 changed files with 417 additions and 0 deletions
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82
gdb-static-tls-1of2.patch Normal file
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@ -0,0 +1,82 @@
http://sourceware.org/ml/gdb-patches/2014-04/msg00154.html
Subject: [patch] Fix gdbserver qGetTLSAddr for x86_64 -m32
--St7VIuEGZ6dlpu13
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Hi,
gdbserver makes libthread_db to access uninitialized memory. Surprisingly it
does not harm normally, even -fsanitize=address works with current gdbserver.
I have found just valgrind detects it as a very first warning for gdbserver:
Syscall param ptrace(addr) contains uninitialised byte(s)
at 0x3721EECEBE: ptrace (ptrace.c:45)
by 0x436EE5: ps_get_thread_area (linux-x86-low.c:252)
by 0x5559D02: __td_ta_lookup_th_unique (td_ta_map_lwp2thr.c:157)
by 0x5559EC3: td_ta_map_lwp2thr (td_ta_map_lwp2thr.c:207)
by 0x43F87D: find_one_thread (thread-db.c:281)
by 0x440038: thread_db_get_tls_address (thread-db.c:505)
by 0x40F6D0: handle_query (server.c:2004)
by 0x4124CF: process_serial_event (server.c:3445)
by 0x4136B6: handle_serial_event (server.c:3889)
by 0x419571: handle_file_event (event-loop.c:434)
by 0x418D38: process_event (event-loop.c:189)
by 0x419AB7: start_event_loop (event-loop.c:552)
Reproducible with:
cd gdb/testsuite
g++ -o gdb.threads/tls gdb.threads/tls{,2}.c -m32 -pthread
../gdbserver/gdbserver :1234 gdb.threads/tls
../gdb -batch gdb.threads/tls -ex 'target remote :1234' -ex 'b spin' -ex c -ex 'p a_thread_local'
It is more easily reproducible even without valgrind using s/0x00/0xff/ in the
attached patch. It will then turn the output of reproducer above:
$1 = 0
->
Cannot find thread-local storage for Thread 29044, executable file .../gdb/testsuite/gdb.threads/tls:
Remote target failed to process qGetTLSAddr request
Thanks,
Jan
--St7VIuEGZ6dlpu13
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline; filename="00ff.patch"
gdb/gdbserver/
2014-04-10 Jan Kratochvil <jan.kratochvil@redhat.com>
Fix gdbserver qGetTLSAddr for x86_64 -m32.
* linux-x86-low.c (X86_64_USER_REGS): New.
(x86_fill_gregset): Call memset for BUF first in x86_64 -m32 case.
diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index 33b5f26..1156e58 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -185,6 +185,7 @@ static const int x86_64_regmap[] =
};
#define X86_64_NUM_REGS (sizeof (x86_64_regmap) / sizeof (x86_64_regmap[0]))
+#define X86_64_USER_REGS (GS + 1)
#else /* ! __x86_64__ */
@@ -343,6 +344,10 @@ x86_fill_gregset (struct regcache *regcache, void *buf)
collect_register (regcache, i, ((char *) buf) + x86_64_regmap[i]);
return;
}
+
+ /* 32-bit inferior registers need to be zero-extended.
+ Callers would read uninitialized memory otherwise. */
+ memset (buf, 0x00, X86_64_USER_REGS * 8);
#endif
for (i = 0; i < I386_NUM_REGS; i++)
--St7VIuEGZ6dlpu13--

326
gdb-static-tls-2of2.patch Normal file
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@ -0,0 +1,326 @@
http://sourceware.org/ml/gdb-patches/2014-04/msg00155.html
Subject: [patch] Fix TLS access for -static -pthread
--qtZFehHsKgwS5rPz
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Hi,
testcase results may depend on patch:
[patch] Fix gdbserver qGetTLSAddr for x86_64 -m32
https://sourceware.org/ml/gdb-patches/2014-04/msg00154.html
Message-ID: <20140410114901.GA16411@host2.jankratochvil.net>
There is:
* gdb.threads/staticthreads.exp to test -static -pthread 'info threads'
* gdb.threads/tls.exp to test TLS access (__thread variables)
but no testcase to test both together - it even does not work.
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.
Future glibcs may implement more native support for -static -pthread TLS
https://sourceware.org/bugzilla/show_bug.cgi?id=16828
which will require also some new GDB support.
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;
No regressions on {x86_64,x86_64-m32}-fedorarawhide-linux-gnu.
Thanks,
Jan
--qtZFehHsKgwS5rPz
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline; filename="staticthread.patch"
gdb/
2014-04-10 Jan Kratochvil <jan.kratochvil@redhat.com>
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/
2014-04-10 Jan Kratochvil <jan.kratochvil@redhat.com>
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/
2014-04-10 Jan Kratochvil <jan.kratochvil@redhat.com>
Fix TLS access for -static -pthread.
* gdb.threads/staticthreads.c <HAVE_TLS> (tlsvar): New.
<HAVE_TLS> (thread_function, main): Initialize it.
* gdb.threads/staticthreads.exp: Try gdb_compile_pthreads for $have_tls.
Add clean_restart.
<$have_tls != "">: Check TLSVAR.
diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c
index ca614a3..4578610 100644
--- a/gdb/linux-thread-db.c
+++ b/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
@@ -799,6 +802,7 @@ try_thread_db_load_1 (struct thread_db_info *info)
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)
{
@@ -1811,21 +1815,34 @@ thread_db_get_thread_local_address (struct target_ops *ops,
info = get_thread_db_info (ptid_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"));
+
+ /* GNU __libc_setup_tls initializes l_tls_modid as 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. */
diff --git a/gdb/target.c b/gdb/target.c
index 1b48f79..fce646c 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -753,10 +753,6 @@ target_translate_tls_address (struct objfile *objfile, CORE_ADDR offset)
/* 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);
diff --git a/gdb/target.h b/gdb/target.h
index d7c6c3d..1aba9e1 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -605,7 +605,8 @@ 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,
diff --git a/gdb/gdbserver/thread-db.c b/gdb/gdbserver/thread-db.c
index f63e39e..f2335ab 100644
--- a/gdb/gdbserver/thread-db.c
+++ b/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_info *thread, CORE_ADDR offset,
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 +514,23 @@ thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
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
+ {
+ /* GNU __libc_setup_tls initializes l_tls_modid as 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 +582,7 @@ 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 +651,7 @@ 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
diff --git a/gdb/testsuite/gdb.threads/staticthreads.c b/gdb/testsuite/gdb.threads/staticthreads.c
index f98f4f1..93bef56 100644
--- a/gdb/testsuite/gdb.threads/staticthreads.c
+++ b/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. */
{
diff --git a/gdb/testsuite/gdb.threads/staticthreads.exp b/gdb/testsuite/gdb.threads/staticthreads.exp
index 80b0ba8..9fa625a 100644
--- a/gdb/testsuite/gdb.threads/staticthreads.exp
+++ b/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 ${binfile}
@@ -89,3 +94,18 @@ gdb_test_multiple "quit" "$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"
+}
--qtZFehHsKgwS5rPz--

9
gdb.spec
View File

@ -544,6 +544,10 @@ Patch852: gdb-gnat-dwarf-crash-3of3.patch
# Fix build failures for GCC 4.9 (Nick Clifton).
Patch864: gcc-4.9-compat.patch
# Fix TLS access for -static -pthread (BZ 1080660).
Patch865: gdb-static-tls-1of2.patch
Patch866: gdb-static-tls-2of2.patch
%if 0%{!?rhel:1} || 0%{?rhel} > 6
# RL_STATE_FEDORA_GDB would not be found for:
# Patch642: gdb-readline62-ask-more-rh.patch
@ -845,6 +849,8 @@ find -name "*.info*"|xargs rm -f
%patch852 -p1
%patch863 -p1
%patch864 -p1
%patch865 -p1
%patch866 -p1
%patch848 -p1
%if 0%{!?el6:1}
@ -1376,6 +1382,9 @@ fi
%endif # 0%{!?el5:1} || "%{_target_cpu}" == "noarch"
%changelog
* Mon May 5 2014 Jan Kratochvil <jan.kratochvil@redhat.com> - 7.7-8.fc21
- Fix TLS access for -static -pthread (BZ 1080660).
* Mon May 5 2014 Jan Kratochvil <jan.kratochvil@redhat.com> - 7.7-7.fc21
- Add GFDL License to the main package (man pages are generated from .texinfo).