[PATCH v2] gdb/riscv: Fix oob memory access when printing info registers

[Ciaran Woodward <ciaranwoodward@xmos.com>]

If the length of a register name was greater than 15,
print_spaces was called with a negative number, which
prints random data from the heap instead of the requested
number of spaces.

This could happen if a target-description file was used
to specify additional long-named registers.

Fix is simple - don't ask for fewer than 1 space (since
we still want column separation).
---

I don't have push privileges, so please can you push this for me!

 gdb/riscv-tdep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdb/riscv-tdep.c b/gdb/riscv-tdep.c
index ae18eb64452..3a2891c2c92 100644
--- a/gdb/riscv-tdep.c
+++ b/gdb/riscv-tdep.c
@@ -1145,7 +1145,7 @@ riscv_print_one_register_info (struct gdbarch *gdbarch,
   enum tab_stops { value_column_1 = 15 };
 
   gdb_puts (name, file);
-  print_spaces (value_column_1 - strlen (name), file);
+  print_spaces (std::max<int> (1, value_column_1 - strlen (name)), file);
 
   try
     {
-- 
2.25.1