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@xxxxxxxxxxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Reported-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Suggested-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
---
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;
/**
--
2.23.0.187.g17f5b7556c-goog
