[lkcd-devel] report has truncated log on SMP/NUMA dumps

[Tommi V. <tv...@de...>]

	Hi. The lcrash/cmds/cmd_stat.c:print_log_buf() routine is
	buggy, it always assumes the log buffer is 16kB. The default
	size is 16kB in UP, 32kB on SMP and 64kB on some NUMA setup.

        Anyway, I think the whole idea of hardcoding the length of the
        kernel define ugly. The dump should contain enough info to get
        the size of log_buf. The following is not tested, but should
        tell what I'm thinking of -- grab the next symbol, size of
        log_buf will be the difference. The "grab next symbol" part,
        or the "get size of this symbol" part, should probably be in
        libklib.

	Oh, does print_log_buf() handle the ring buffer nature of
	log_buf properly?

--- cmd_stat.c.orig	Thu Sep 13 03:37:48 2001
+++ cmd_stat.c	Sun Jan 13 22:34:31 2002
@@ -3,8 +3,6 @@
  */
 #include <lcrash.h>
 
-#define LOG_BUF_SIZE 16384
-
 void
 print_log_buf(FILE *ofp)    
 {
@@ -13,18 +11,22 @@
 	kaddr_t symaddr;
 	syment_t *sp;
 
-	if (!(lbuf = (char *)malloc(LOG_BUF_SIZE))) {
-		return;
-	}
-	if (!(np = (char *)malloc(256))) {
-		free(lbuf);
-		return;
-	}
 	if ((sp = kl_lkup_symname("log_buf"))) {
 		symaddr = sp->s_addr;
 	} else {
 		fprintf(stderr, "Could not find the symbol \"log_buf\"\n");
-		free(np);
+		return;
+	}
+
+	if (!(sp = (syment_t *)kl_next_btnode(&sp->s_bt))) {
+		fprintf(stderr, "Could not find the size of symbol \"log_buf\"\n");
+		return;
+	}
+	
+	if (!(lbuf = (char *)malloc(sp->s_addr - symaddr))) {
+		return;
+	}
+	if (!(np = (char *)malloc(256))) {
 		free(lbuf);
 		return;
 	}

-- 
tv@{{hq.yok.utu,havoc,gaeshido}.fi,{debian,wanderer}.org,stonesoft.com}
double a,b=4,c;main(){for(;++a<2e6;c-=(b=-b)/a++);printf("%f\n",c);}