[PATCH 05/17] lto: Handle LTO common symbols in module loader

From: Andi Kleen
Date: Sat Feb 08 2014 - 03:06:55 EST


From: Joe Mario <jmario@xxxxxxxxxx>

Here is the workaround I made for having the kernel not reject modules
built with -flto. The clean solution would be to get the compiler to not
emit the symbol. Or if it has to emit the symbol, then emit it as
initialized data but put it into a comdat/linkonce section.

Minor tweaks by AK over Joe's patch.

Cc: rusty@xxxxxxxxxxxxxxx
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
kernel/module.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/kernel/module.c b/kernel/module.c
index d24fcf2..b99e801 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1948,6 +1948,10 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)

switch (sym[i].st_shndx) {
case SHN_COMMON:
+ /* Ignore common symbols */
+ if (!strncmp(name, "__gnu_lto", 9))
+ break;
+
/* We compiled with -fno-common. These are not
supposed to happen. */
pr_debug("Common symbol: %s\n", name);
--
1.8.5.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/