RISC-V: Fix elfutils testsuite unwind failures.

The clone.S patch fixes 2 elfutils testsuite unwind failures, where the
backtrace gets stuck repeating __thread_start until we hit the backtrace
limit.  This was confirmed by building and installing a patched glibc and
then building elfutils and running its testsuite.

Unfortunately, the testcase isn't working as expected and I don't know why.
The testcase passes even when my clone.S patch is not installed.  The testcase
looks logically similarly to the elfutils testcases that are failing.  Maybe
there is a subtle difference in how the glibc unwinding works versus the
elfutils unwinding?  I don't have good gdb pthread support yet, so I haven't
found a way to debug this.  Anyways, I don't know if the testcase is useful or
not.  If the testcase isn't useful then maybe the clone.S patch is OK without
a testcase?

Jim

	[BZ #24040]
	* elf/Makefile (CFLAGS-tst-unwind-main.c): Add -DUSE_PTHREADS=0.
	* elf/tst-unwind-main.c: If USE_PTHEADS, include pthread.h and error.h
	(func): New.
	(main): If USE_PTHREADS, call pthread_create to run func.  Otherwise
	call func directly.
	* nptl/Makefile (tests): Add tst-unwind-thread.
	(CFLAGS-tst-unwind-thread.c): Define.
	* nptl/tst-unwind-thread.c: New file.
	* sysdeps/unix/sysv/linux/riscv/clone.S (__thread_start): Mark ra
	as undefined.

(cherry picked from commit 85bd1ddbdfdfd13cfd06f7c367519b6ed3360843)

diff --git a/ChangeLog b/ChangeLog
index 06de839fbe88e25d332bfcd3188f8786fae67375..0087fd9d50c96f9c97848b7b92406ef6b07f7185 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2019-01-13  Jim Wilson  <jimw@sifive.com>
+
+       [BZ #24040]
+       * elf/Makefile (CFLAGS-tst-unwind-main.c): Add -DUSE_PTHREADS=0.
+       * elf/tst-unwind-main.c: If USE_PTHEADS, include pthread.h and error.h
+       (func): New.
+       (main): If USE_PTHREADS, call pthread_create to run func.  Otherwise
+       call func directly.
+       * nptl/Makefile (tests): Add tst-unwind-thread.
+       (CFLAGS-tst-unwind-thread.c): Define.
+       * nptl/tst-unwind-thread.c: New file.
+       * sysdeps/unix/sysv/linux/riscv/clone.S (__thread_start): Mark ra
+       as undefined.
+
 2019-01-31  Carlos O'Donell  <carlos@redhat.com>
            Torvald Riegel  <triegel@redhat.com>
            Rik Prohaska  <prohaska7@gmail.com>

diff --git a/NEWS b/NEWS
index d794e5bf095d19b401796b159a960e6382648658..2d5a514dfd4aca6083ac3842dc9592eface92229 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -36,6 +36,7 @@ The following bugs are resolved with this release:
   [24024] strerror() might set errno to ENOMEM due to -fno-math-error
   [24027] malloc: Integer overflow in realloc
   [24034] tst-cancel21-static fails with SIGBUS on pre-ARMv7 when using GCC 8
+  [24040] riscv64: unterminated call chain in __thread_start
   [24097] Can't use 64-bit register for size_t in assembly codes for x32 (CVE-2019-6488)
   [24155] x32 memcmp can treat positive length as 0 (if sign bit in RDX is set) (CVE-2019-7309)
   [24161] __run_fork_handlers self-deadlocks in malloc/tst-mallocfork2

diff --git a/elf/Makefile b/elf/Makefile
index 43f625af05699d5ca520a1a9d7a9ecfed58b9731..6027926bd16fea2dd93f4f87a0fc2ef670850527 100644 (file)
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -1486,4 +1486,4 @@ $(objpfx)tst-libc_dlvsym-static.out: $(objpfx)tst-libc_dlvsym-dso.so
 
 $(objpfx)tst-big-note: $(objpfx)tst-big-note-lib.so
 
-CFLAGS-tst-unwind-main.c += -funwind-tables
+CFLAGS-tst-unwind-main.c += -funwind-tables -DUSE_PTHREADS=0

diff --git a/elf/tst-unwind-main.c b/elf/tst-unwind-main.c
index d1236032d77853fe409f9e2d6199329ea26fbc23..7c20f04743d256980a64556e316c1ec1a17134f0 100644 (file)
--- a/elf/tst-unwind-main.c
+++ b/elf/tst-unwind-main.c
@@ -20,19 +20,41 @@
 #include <unistd.h>
 #include <support/test-driver.h>
 
+#if USE_PTHREADS
+# include <pthread.h>
+# include <error.h>
+#endif
+
 static _Unwind_Reason_Code
 callback (struct _Unwind_Context *ctx, void *arg)
 {
   return _URC_NO_REASON;
 }
 
-int
-main (void)
+static void *
+func (void *a)
 {
   /* Arrange for this test to be killed if _Unwind_Backtrace runs into an
      endless loop.  We cannot use the test driver because the complete
      call chain needs to be compiled with -funwind-tables so that
-     _Unwind_Backtrace is able to reach _start.  */
+     _Unwind_Backtrace is able to reach the start routine.  */
   alarm (DEFAULT_TIMEOUT);
   _Unwind_Backtrace (callback, 0);
+  return a;
+}
+
+int
+main (void)
+{
+#if USE_PTHREADS
+  pthread_t thr;
+  int rc = pthread_create (&thr, NULL, &func, NULL);
+  if (rc)
+    error (1, rc, "pthread_create");
+  rc = pthread_join (thr, NULL);
+  if (rc)
+    error (1, rc, "pthread_join");
+#else
+  func (NULL);
+#endif
 }

diff --git a/nptl/Makefile b/nptl/Makefile
index b1003cf56b31ddfa4ccc6072846f895c21eba078..5be76555296c99c9a7fdcb545ce4805ad76c92b8 100644 (file)
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -320,7 +320,8 @@ tests = tst-attr1 tst-attr2 tst-attr3 tst-default-attr \
        tst-cnd-timedwait tst-thrd-detach tst-mtx-basic tst-thrd-sleep \
        tst-mtx-recursive tst-tss-basic tst-call-once tst-mtx-timedlock \
        tst-rwlock-pwn \
-       tst-rwlock-tryrdlock-stall tst-rwlock-trywrlock-stall
+       tst-rwlock-tryrdlock-stall tst-rwlock-trywrlock-stall \
+       tst-unwind-thread
 
 tests-internal := tst-rwlock19 tst-rwlock20 \
                  tst-sem11 tst-sem12 tst-sem13 \
@@ -723,6 +724,8 @@ $(objpfx)tst-audit-threads: $(objpfx)tst-audit-threads-mod2.so
 $(objpfx)tst-audit-threads.out: $(objpfx)tst-audit-threads-mod1.so
 tst-audit-threads-ENV = LD_AUDIT=$(objpfx)tst-audit-threads-mod1.so
 
+CFLAGS-tst-unwind-thread.c += -funwind-tables
+
 # The tests here better do not run in parallel
 ifneq ($(filter %tests,$(MAKECMDGOALS)),)
 .NOTPARALLEL:

diff --git a/nptl/tst-unwind-thread.c b/nptl/tst-unwind-thread.c
new file mode 100644 (file)
index 0000000..d5c38e3
--- /dev/null
+++ b/nptl/tst-unwind-thread.c
@@ -0,0 +1,2 @@
+#define USE_PTHREADS 1
+#include "../elf/tst-unwind-main.c"

diff --git a/sysdeps/unix/sysv/linux/riscv/clone.S b/sysdeps/unix/sysv/linux/riscv/clone.S
index 392af72b55daacf081e6ffbdbeba028b5e120d64..1c5b12566e4c23cd08d75bca69b225e166c303b9 100644 (file)
--- a/sysdeps/unix/sysv/linux/riscv/clone.S
+++ b/sysdeps/unix/sysv/linux/riscv/clone.S
@@ -69,6 +69,11 @@ L (error):
 
 ENTRY (__thread_start)
 L (thread_start):
+       /* Terminate call stack by noting ra is undefined.  Use a dummy
+          .cfi_label to force starting the FDE.  */
+       .cfi_label .Ldummy
+       cfi_undefined (ra)
+
        /* Restore the arg for user's function.  */
        REG_L           a1,0(sp)        /* Function pointer.  */
        REG_L           a0,SZREG(sp)    /* Argument pointer.  */