GCC unescapes escaped string section names while Clang does not. Because __section uses the `#` stringification operator for the section name, it doesn't need to be escaped.
This fixes an Oops observed in distro's that use systemd and not net.core.bpf_jit_enable=1, when their kernels are compiled with Clang.
Instead, we should: 1. Prefer __section(.section_name_no_quotes). 2. Only use __attribute__((__section(".section"))) when creating the section name via C preprocessor (see the definition of __define_initcall in arch/um/include/shared/init.h).
This antipattern was found with: $ grep -e __section(" -e __section__(" -r
See the discussions in: Link: https://bugs.llvm.org/show_bug.cgi?id=42950 Link: https://marc.info/?l=linux-netdev&m=156412960619946&w=2 Link: Link: https://github.com/ClangBuiltLinux/linux/issues/619 Cc: stable@vger.kernel.org Acked-by: Will Deacon will@kernel.org Reported-by: Sedat Dilek sedat.dilek@gmail.com Suggested-by: Josh Poimboeuf jpoimboe@redhat.com Tested-by: Sedat Dilek sedat.dilek@gmail.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com --- include/linux/compiler.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index f0fd5636fddb..5e88e7e33abe 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -24,7 +24,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, long ______r; \ static struct ftrace_likely_data \ __aligned(4) \ - __section("_ftrace_annotated_branch") \ + __section(_ftrace_annotated_branch) \ ______f = { \ .data.func = __func__, \ .data.file = __FILE__, \ @@ -60,7 +60,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, #define __trace_if_value(cond) ({ \ static struct ftrace_branch_data \ __aligned(4) \ - __section("_ftrace_branch") \ + __section(_ftrace_branch) \ __if_trace = { \ .func = __func__, \ .file = __FILE__, \ @@ -118,7 +118,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, ".popsection\n\t"
/* Annotate a C jump table to allow objtool to follow the code flow */ -#define __annotate_jump_table __section(".rodata..c_jump_table") +#define __annotate_jump_table __section(.rodata..c_jump_table)
#else #define annotate_reachable() @@ -298,7 +298,7 @@ unsigned long read_word_at_a_time(const void *addr) * visible to the compiler. */ #define __ADDRESSABLE(sym) \ - static void * __section(".discard.addressable") __used \ + static void * __section(.discard.addressable) __used \ __PASTE(__addressable_##sym, __LINE__) = (void *)&sym;
/**