[PATCH 4.4 031/114] um: Avoid longjmp/setjmp symbol clashes with libpthread.a

Greg Kroah-Hartman
2018-11-08T21:50:46Z

[ Upstream commit f44f1e7da7c8e3f4575d5d61c4df978496903fcc ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/um/Makefile | 4 ++++
arch/x86/um/setjmp_32.S | 16 ++++++++--------
arch/x86/um/setjmp_64.S | 16 ++++++++--------
3 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/arch/um/Makefile b/arch/um/Makefile
index 9ccf462131c4..d9cd7ed27834 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

diff --git a/arch/x86/um/setjmp_32.S b/arch/x86/um/setjmp_32.S
index b766792c9933..39053192918d 100644
--- a/arch/x86/um/setjmp_32.S
+++ b/arch/x86/um/setjmp_32.S
@@ -16,9 +16,9 @@

.text
.align 4
- .globl setjmp
- .type setjmp, @function
-setjmp:
+ .globl kernel_setjmp
+ .type kernel_setjmp, @function
+kernel_setjmp:
#ifdef _REGPARM
movl %eax,%edx
#else
@@ -35,13 +35,13 @@ setjmp:
movl %ecx,20(%edx) # Return address
ret

- .size setjmp,.-setjmp
+ .size kernel_setjmp,.-kernel_setjmp

.text
.align 4
- .globl longjmp
- .type longjmp, @function
-longjmp:
+ .globl kernel_longjmp
+ .type kernel_longjmp, @function
+kernel_longjmp:
#ifdef _REGPARM
xchgl %eax,%edx
#else
@@ -55,4 +55,4 @@ longjmp:
movl 16(%edx),%edi
jmp *20(%edx)

- .size longjmp,.-longjmp
+ .size kernel_longjmp,.-kernel_longjmp
diff --git a/arch/x86/um/setjmp_64.S b/arch/x86/um/setjmp_64.S
index 45f547b4043e..c56942e1a38c 100644
--- a/arch/x86/um/setjmp_64.S
+++ b/arch/x86/um/setjmp_64.S
@@ -18,9 +18,9 @@

.text
.align 4
- .globl setjmp
- .type setjmp, @function
-setjmp:
+ .globl kernel_setjmp
+ .type kernel_setjmp, @function
+kernel_setjmp:
pop %rsi # Return address, and adjust the stack
xorl %eax,%eax # Return value
movq %rbx,(%rdi)
@@ -34,13 +34,13 @@ setjmp:
movq %rsi,56(%rdi) # Return address
ret

- .size setjmp,.-setjmp
+ .size kernel_setjmp,.-kernel_setjmp

.text
.align 4
- .globl longjmp
- .type longjmp, @function
-longjmp:
+ .globl kernel_longjmp
+ .type kernel_longjmp, @function
+kernel_longjmp:
movl %esi,%eax # Return value (int)
movq (%rdi),%rbx
movq 8(%rdi),%rsp
@@ -51,4 +51,4 @@ longjmp:
movq 48(%rdi),%r15
jmp *56(%rdi)

- .size longjmp,.-longjmp
+ .size kernel_longjmp,.-kernel_longjmp
--
2.17.1