From: Sami Tolvanen <samitolvanen@xxxxxxxxxx> [ Upstream commit 983df5f2699f83f78643b19d3399b160d1e64f5b ] my_tramp[12]? are declared as global functions in C, but they are not marked global in the inline assembly definition. This mismatch confuses Clang's Control-Flow Integrity checking. Fix the definitions by adding .globl. Link: https://lkml.kernel.org/r/20201113183414.1446671-1-samitolvanen@xxxxxxxxxx Fixes: 9d907f1ae80b8 ("ftrace/samples: Add a sample module that implements modify_ftrace_direct()") Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- samples/ftrace/ftrace-direct-modify.c | 2 ++ samples/ftrace/ftrace-direct-too.c | 1 + samples/ftrace/ftrace-direct.c | 1 + 3 files changed, 4 insertions(+) diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c index c13a5bc5095be..5b9a09957c6e0 100644 --- a/samples/ftrace/ftrace-direct-modify.c +++ b/samples/ftrace/ftrace-direct-modify.c @@ -21,6 +21,7 @@ static unsigned long my_ip = (unsigned long)schedule; asm ( " .pushsection .text, \"ax\", @progbits\n" " .type my_tramp1, @function\n" +" .globl my_tramp1\n" " my_tramp1:" " pushq %rbp\n" " movq %rsp, %rbp\n" @@ -29,6 +30,7 @@ asm ( " .size my_tramp1, .-my_tramp1\n" " ret\n" " .type my_tramp2, @function\n" +" .globl my_tramp2\n" " my_tramp2:" " pushq %rbp\n" " movq %rsp, %rbp\n" diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c index d5c5022be6642..3f0079c9bd6fa 100644 --- a/samples/ftrace/ftrace-direct-too.c +++ b/samples/ftrace/ftrace-direct-too.c @@ -16,6 +16,7 @@ extern void my_tramp(void *); asm ( " .pushsection .text, \"ax\", @progbits\n" " .type my_tramp, @function\n" +" .globl my_tramp\n" " my_tramp:" " pushq %rbp\n" " movq %rsp, %rbp\n" diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c index 63ca06d42c803..a2729d1ef17f5 100644 --- a/samples/ftrace/ftrace-direct.c +++ b/samples/ftrace/ftrace-direct.c @@ -14,6 +14,7 @@ extern void my_tramp(void *); asm ( " .pushsection .text, \"ax\", @progbits\n" " .type my_tramp, @function\n" +" .globl my_tramp\n" " my_tramp:" " pushq %rbp\n" " movq %rsp, %rbp\n" -- 2.27.0
