1.0.26.8: QSHOW changes, bug reporting guidelines

- change runtime.h so that a simple '#define QSHOW_SIGNAL 1' turns
QSHOW automatically and defaults to blocking signals during printing

- add notes to BUGS on how to report bugs related to signal handling

- kill a warning in thread.c in code conditional on QSHOW_SIGNAL

- add #include <stdio.h> to x86{-64,}-darwin-os.c so that it compiles
  with QSHOW

- add comment explaining the previous commit

diff --git a/BUGS b/BUGS
index 0c6e139..1cb8b2c 100644 (file)
--- a/BUGS
+++ b/BUGS
@@ -21,6 +21,36 @@ but instead
        (MAKE-FOO)
      the program loops endlessly instead of printing the object.
 
+If you run into a signal related bug, you are getting fatal errors
+such as 'signal N is [un]blocked' or just hangs, and you want to send
+a useful bug report then:
+
+- compile sbcl with ldb support (feature :sb-ldb, see
+  base-target-features.lisp-expr) and change '#define QSHOW_SIGNAL 0'
+  to '#define QSHOW_SIGNAL 1' in src/runtime/runtime.h.
+
+- isolate a smallish test case, run it
+
+- if it just hangs kill it with sigabrt: kill -ABRT <pidof sbcl>
+
+- print the backtrace from ldb by typing 'ba'
+
+- attach gdb: gdb -p <pidof sbcl> and get backtraces for all threads:
+  thread apply all ba
+
+- if multiple threads are in play then still in gdb, try to get Lisp
+  backtrace for all threads: 'thread apply all
+  call_backtrace_from_fp($ebp, 100)'. Substitute $ebp with $rbp on
+  x86-64.
+
+- send a report with the backtraces and the output (both stdout,
+  stderr) produced by sbcl
+
+- don't forget to include OS and SBCL version
+
+- if available include info on outcome of the same test with other
+  versions of SBCL, OS, ...
+
 
 NOTES:
 

diff --git a/src/runtime/gencgc.c b/src/runtime/gencgc.c
index 3353425..c87669e 100644 (file)
--- a/src/runtime/gencgc.c
+++ b/src/runtime/gencgc.c
@@ -89,7 +89,7 @@ long large_object_size = 4 * PAGE_BYTES;
 
 /* the verbosity level. All non-error messages are disabled at level 0;
  * and only a few rare messages are printed at level 1. */
-#ifdef QSHOW
+#if QSHOW
 boolean gencgc_verbose = 1;
 #else
 boolean gencgc_verbose = 0;
@@ -384,7 +384,7 @@ count_generation_pages(generation_index_t generation)
     return count;
 }
 
-#ifdef QSHOW
+#if QSHOW
 static long
 count_dont_move_pages(void)
 {
@@ -1684,7 +1684,7 @@ sniff_code_object(struct code *code, unsigned long displacement)
         unsigned d2 = *((unsigned char *)p - 2);
         unsigned d3 = *((unsigned char *)p - 3);
         unsigned d4 = *((unsigned char *)p - 4);
-#ifdef QSHOW
+#if QSHOW
         unsigned d5 = *((unsigned char *)p - 5);
         unsigned d6 = *((unsigned char *)p - 6);
 #endif
@@ -4096,7 +4096,7 @@ garbage_collect_generation(generation_index_t generation, int raise)
     }
 #endif
 
-#ifdef QSHOW
+#if QSHOW
     if (gencgc_verbose > 1) {
         long num_dont_move_pages = count_dont_move_pages();
         fprintf(stderr,
@@ -4808,7 +4808,7 @@ gencgc_handle_wp_violation(void* fault_addr)
 {
     page_index_t page_index = find_page_index(fault_addr);
 
-#ifdef QSHOW_SIGNALS
+#if QSHOW_SIGNALS
     FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
            fault_addr, page_index));
 #endif

diff --git a/src/runtime/interrupt.c b/src/runtime/interrupt.c
index b6c5c0d..dc210e9 100644 (file)
--- a/src/runtime/interrupt.c
+++ b/src/runtime/interrupt.c
@@ -682,7 +682,7 @@ interrupt_internal_error(os_context_t *context, boolean continuable)
 #endif
 
     SHOW("in interrupt_internal_error");
-#ifdef QSHOW
+#if QSHOW
     /* Display some rudimentary debugging information about the
      * error, so that even if the Lisp error handler gets badly
      * confused, we have a chance to determine what's going on. */

diff --git a/src/runtime/linux-os.h b/src/runtime/linux-os.h
index f1a84e9..6f1003c 100644 (file)
--- a/src/runtime/linux-os.h
+++ b/src/runtime/linux-os.h
@@ -39,4 +39,8 @@ typedef int os_vm_prot_t;
 
 #define SIG_MEMORY_FAULT SIGSEGV
 
+/* Note that this must be higher than the highest numbered
+ * synchronously generated signal that we handle (that is SIGSEGV),
+ * due to Linux signal handling pecularities. See thread "Signal
+ * delivery order" from 2009-03-14 on kernel-devel@vger.kernel.org. */
 #define SIG_STOP_FOR_GC (SIGUSR2)

diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index 01f4031..bda2896 100644 (file)
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -29,12 +29,27 @@
 #define thread_mutex_unlock(l) 0
 #endif
 
-/* #define QSHOW */ /* Enable low-level debugging output? */
-/* #define QSHOW_SAFE */ /* Enable blocking interrupts for each SHOW. */
+/* Block blockable interrupts for each SHOW, if not 0. */
+#define QSHOW_SIGNAL_SAFE 1
+/* Enable extra-verbose low-level debugging output for signals? (You
+ * probably don't want this unless you're trying to debug very early
+ * cold boot on a new machine, or one where you've just messed up
+ * signal handling.)
+ *
+ * Note: It may be that doing this is fundamentally unsound, since it
+ * causes output from signal handlers, and the i/o libraries aren't
+ * necessarily reentrant. But it can still be very convenient for
+ * figuring out what's going on when you have a signal handling
+ * problem. */
+#define QSHOW_SIGNALS 0
+/* Enable low-level debugging output, if not zero. Defaults to enabled
+ * if QSHOW_SIGNALS, disabled otherwise. Change it to 1 if you want
+ * low-level debugging output but not the whole signal mess. */
+#define QSHOW QSHOW_SIGNALS
 
-#ifdef QSHOW
+#if QSHOW
 
-#ifdef QSHOW_SAFE
+#if QSHOW_SIGNAL_SAFE
 
 #include <signal.h>
 extern sigset_t blockable_sigset;
@@ -70,18 +85,6 @@ extern sigset_t blockable_sigset;
 
 #endif
 
-/* Enable extra-verbose low-level debugging output for signals? (You
- * probably don't want this unless you're trying to debug very early
- * cold boot on a new machine, or one where you've just messed up
- * signal handling.)
- *
- * Note: It may be that doing this is fundamentally unsound, since it
- * causes output from signal handlers, and the i/o libraries aren't
- * necessarily reentrant. But it can still be very convenient for
- * figuring out what's going on when you have a signal handling
- * problem.. */
-#define QSHOW_SIGNALS 0
-
 #if QSHOW_SIGNALS
 #define FSHOW_SIGNAL FSHOW
 #else

diff --git a/src/runtime/thread.c b/src/runtime/thread.c
index e158680..f8cb1ca 100644 (file)
--- a/src/runtime/thread.c
+++ b/src/runtime/thread.c
@@ -523,13 +523,15 @@ boolean create_os_thread(struct thread *th,os_thread_t *kid_tid)
 #endif
 
     if((initcode = pthread_attr_init(th->os_attr)) ||
-       /* call_into_lisp_first_time switches the stack for the initial thread. For the
-        * others, we use this. */
-       (pthread_attr_setstack(th->os_attr,th->control_stack_start,thread_control_stack_size)) ||
+       /* call_into_lisp_first_time switches the stack for the initial
+        * thread. For the others, we use this. */
+       (pthread_attr_setstack(th->os_attr,th->control_stack_start,
+                              thread_control_stack_size)) ||
        (retcode = pthread_create
         (kid_tid,th->os_attr,(void *(*)(void *))new_thread_trampoline,th))) {
         FSHOW_SIGNAL((stderr, "init = %d\n", initcode));
-        FSHOW_SIGNAL((stderr, printf("pthread_create returned %d, errno %d\n", retcode, errno)));
+        FSHOW_SIGNAL((stderr, "pthread_create returned %d, errno %d\n",
+                      retcode, errno));
         if(retcode < 0) {
             perror("create_os_thread");
         }

diff --git a/src/runtime/x86-64-darwin-os.c b/src/runtime/x86-64-darwin-os.c
index 1b7df60..35ac2f9 100644 (file)
--- a/src/runtime/x86-64-darwin-os.c
+++ b/src/runtime/x86-64-darwin-os.c
@@ -1,4 +1,3 @@
-
 #ifdef LISP_FEATURE_SB_THREAD
 #include <architecture/i386/table.h>
 #include <i386/user_ldt.h>

diff --git a/src/runtime/x86-darwin-os.c b/src/runtime/x86-darwin-os.c
index 2c2b978..1cc837c 100644 (file)
--- a/src/runtime/x86-darwin-os.c
+++ b/src/runtime/x86-darwin-os.c
@@ -1,5 +1,3 @@
-
-
 #ifdef LISP_FEATURE_SB_THREAD
 #include <architecture/i386/table.h>
 #include <i386/user_ldt.h>
@@ -25,6 +23,7 @@
 #include <pthread.h>
 #include <assert.h>
 #include <stdlib.h>
+#include <stdio.h>
 
 #ifdef LISP_FEATURE_SB_THREAD
 

diff --git a/version.lisp-expr b/version.lisp-expr
index 27ef673..31175e6 100644 (file)
--- a/version.lisp-expr
+++ b/version.lisp-expr
@@ -17,4 +17,4 @@
 ;;; checkins which aren't released. (And occasionally for internal
 ;;; versions, especially for internal versions off the main CVS
 ;;; branch, it gets hairier, e.g. "0.pre7.14.flaky4.13".)
-"1.0.26.7"
+"1.0.26.8"