Commit 5cfb203a authored Aug 08, 2015 by Takashi Iwai Committed by Rusty Russell Aug 08, 2015

modpost: abort if a module symbol is too long



Module symbols have a limited length, but currently the build system
allows the build finishing even if the driver code contains a too long
symbol name, which eventually overflows the modversion_info[] item.
The compiler may catch at compiling *.mod.c like
  CC      xxx.mod.o
  xxx.mod.c:18:16: warning: initializer-string for array of chars is too long
but it's merely a warning.

This patch adds the check of the symbol length in modpost and stops
the build properly.

Currently MODULE_NAME_LEN is defined in modpost.c instead of referring
to the definition in kernel header because including linux/module.h is
messy and we must cover cross-compilation.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

parent dd2384a7

scripts/mod/modpost.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -2133,6 +2133,11 @@ static void add_staging_flag(struct buffer b, const char name)
		buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
		}

		/* In kernel, this size is defined in linux/module.h;
		* here we use Elf_Addr instead of long for covering cross-compile
		*/
		#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))

		/**
		* Record CRCs for unresolved symbols
		**/
		@@ -2177,6 +2182,12 @@ static int add_versions(struct buffer b, struct module mod)
		s->name, mod->name);
		continue;
		}
		if (strlen(s->name) >= MODULE_NAME_LEN) {
		merror("too long symbol \"%s\" [%s.ko]\n",
		s->name, mod->name);
		err = 1;
		break;
		}
		buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
		s->crc, s->name);
		}