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authorFlorian Fainelli <f.fainelli@gmail.com>2017-05-23 17:32:31 -0700
committerRichard Weinberger <richard@nod.at>2017-07-05 23:30:50 +0200
commitf44f1e7da7c8e3f4575d5d61c4df978496903fcc (patch)
tree237c2be6138a7d6aa516989a85f144e14891ec69 /arch/um
parent745a600cf1a6230f5e3910c340dcb312b718e114 (diff)
downloadlinux-f44f1e7da7c8e3f4575d5d61c4df978496903fcc.tar.gz
um: Avoid longjmp/setjmp symbol clashes with libpthread.a
Building a statically linked UML kernel on a Centos 6.9 host resulted in
the following linking failure (GCC 4.4, glibc-2.12):

/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/libpthread.a(libpthread.o):
In function `siglongjmp':
(.text+0x8490): multiple definition of `longjmp'
arch/x86/um/built-in.o:/local/users/fainelli/openwrt/trunk/build_dir/target-x86_64_musl/linux-uml/linux-4.4.69/arch/x86/um/setjmp_64.S:44:
first defined here
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/libpthread.a(libpthread.o):
In function `sem_open':
(.text+0x77cd): warning: the use of `mktemp' is dangerous, better use
`mkstemp'
collect2: ld returned 1 exit status
make[4]: *** [vmlinux] Error 1

Adopt a solution similar to the one done for vmap where we define
longjmp/setjmp to be kernel_longjmp/setjmp. In the process, make sure we
do rename the functions in arch/x86/um/setjmp_*.S accordingly.

Fixes: a7df4716d195 ("um: link with -lpthread")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/Makefile4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/um/Makefile b/arch/um/Makefile
index 0ca46ededfc7..6ca4f66085c1 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -59,10 +59,14 @@ KBUILD_CPPFLAGS += -I$(srctree)/$(HOST_DIR)/um
 # Same things for in6addr_loopback and mktime - found in libc. For these two we
 # only get link-time error, luckily.
 #
+# -Dlongjmp=kernel_longjmp prevents anything from referencing the libpthread.a
+# embedded copy of longjmp, same thing for setjmp.
+#
 # These apply to USER_CFLAGS to.
 
 KBUILD_CFLAGS += $(CFLAGS) $(CFLAGS-y) -D__arch_um__ \
 	$(ARCH_INCLUDE) $(MODE_INCLUDE) -Dvmap=kernel_vmap	\
+	-Dlongjmp=kernel_longjmp -Dsetjmp=kernel_setjmp \
 	-Din6addr_loopback=kernel_in6addr_loopback \
 	-Din6addr_any=kernel_in6addr_any -Dstrrchr=kernel_strrchr