[PATCH 3/3] crash-trace-command: Update crash to handle new bprintk format structure

[Steven Rostedt <rostedt@xxxxxxxxxxx>]

The bprintk format structure may change in the near future. Update the
reading of the structure to comply with the change.

Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

Index: crash-5.1.3/extensions/trace.c
===================================================================
--- crash-5.1.3.orig/extensions/trace.c
+++ crash-5.1.3/extensions/trace.c
@@ -3383,6 +3383,7 @@ static int save_ftrace_printk(int fd)
 	long bprintk_fmt_s, bprintk_fmt_e;
 	long *address;
 	size_t i, count, len;
+	int addr_is_array = 0;
 
 	s = symbol_search("__start___trace_bprintk_fmt");
 	e = symbol_search("__stop___trace_bprintk_fmt");
@@ -3393,10 +3394,8 @@ static int save_ftrace_printk(int fd)
 	bprintk_fmt_e = e->value;
 	count = (bprintk_fmt_e - bprintk_fmt_s) / sizeof(long);
 
-	if (count == 0) {
-		unsigned int size = 0;
-		return write_and_check(fd, &size, 4);
-	}
+	if (count == 0)
+		goto do_mods;
 
 	address = malloc(count * sizeof(long));
 	if (address == NULL)
@@ -3417,11 +3416,23 @@ static int save_ftrace_printk(int fd)
 
 	free(address);
 
+ do_mods:
+
 	/* Add modules */
 	b = symbol_search("trace_bprintk_fmt_list");
 	if (!b)
 		goto out;
 
+	switch (MEMBER_TYPE("trace_bprintk_fmt", "fmt")) {
+	case TYPE_CODE_ARRAY:
+		addr_is_array = 1;
+		break;
+	case TYPE_CODE_PTR:
+	default:
+		/* default not array */
+		break;
+	}
+
 	mod_fmt = (struct kernel_list_head *)GETBUF(SIZE(list_head));
 	if (!readmem(b->value, KVADDR, mod_fmt,
 		     SIZE(list_head), "trace_bprintk_fmt_list contents",
@@ -3432,6 +3443,12 @@ static int save_ftrace_printk(int fd)
 		unsigned long addr;
 
 		addr = (unsigned long)mod_fmt->next + SIZE(list_head);
+		if (!addr_is_array) {
+			if (!readmem(addr, KVADDR, &addr, sizeof(addr),
+				     "trace_bprintk_fmt_list fmt field",
+				     RETURN_ON_ERROR))
+				goto out_free;
+		}
 
 		if (!readmem((unsigned long)mod_fmt->next, KVADDR, mod_fmt,
 			     SIZE(list_head), "trace_bprintk_fmt_list contents",
@@ -3440,15 +3457,20 @@ static int save_ftrace_printk(int fd)
 
 		if (add_print_address(addr) < 0)
 			goto out_free;
+		count++;
 	}
 
  out_free:
-
 	FREEBUF(mod_fmt);
  out:
+	if (count == 0) {
+		unsigned int size = 0;
+		return write_and_check(fd, &size, 4);
+	}
 	if (tmp_file_record_size4(fd))
 		return -1;
 	return tmp_file_flush(fd);
+
 }
 
 static int save_ftrace_cmdlines(int fd)

--
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