kallsyms: increase maximum kernel symbol length to 512

Rust symbols can become quite long due to namespacing introduced
by modules, types, traits, generics, etc. For instance,
the following code:

    pub mod my_module {
        pub struct MyType;
        pub struct MyGenericType<T>(T);

        pub trait MyTrait {
            fn my_method() -> u32;
        }

        impl MyTrait for MyGenericType<MyType> {
            fn my_method() -> u32 {
                42
            }
        }
    }

generates a symbol of length 96 when using the upcoming v0 mangling scheme:

    _RNvXNtCshGpAVYOtgW1_7example9my_moduleINtB2_13MyGenericTypeNtB2_6MyTypeENtB2_7MyTrait9my_method

At the moment, Rust symbols may reach up to 300 in length.
Setting 512 as the maximum seems like a reasonable choice to
keep some headroom.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index ad39636..649faac 100644 (file)
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -15,7 +15,7 @@
 
 #include <asm/sections.h>
 
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 512
 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s %s]") + \
                        (KSYM_NAME_LEN - 1) + \
                        2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + \

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index bc475e6..ec06ce5 100644 (file)
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -213,7 +213,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
         * we use the smallest/strictest upper bound possible (56, based on
         * the current definition of MODULE_NAME_LEN) to prevent overflows.
         */
-       BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);
+       BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 512);
 
        relas = (Elf_Rela *) relasec->sh_addr;
        /* For each rela in this klp relocation section */
@@ -227,7 +227,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
 
                /* Format: .klp.sym.sym_objname.sym_name,sympos */
                cnt = sscanf(strtab + sym->st_name,
-                            ".klp.sym.%55[^.].%127[^,],%lu",
+                            ".klp.sym.%55[^.].%511[^,],%lu",
                             sym_objname, sym_name, &sympos);
                if (cnt != 3) {
                        pr_err("symbol %s has an incorrectly formatted name\n",

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 6502c40..c479330 100644 (file)
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -30,7 +30,7 @@
 #define _stringify_1(x)        #x
 #define _stringify(x)  _stringify_1(x)
 
-#define KSYM_NAME_LEN          128
+#define KSYM_NAME_LEN          512
 
 /*
  * A substantially bigger size than the current maximum.
@@ -39,7 +39,7 @@
  * for the fscanf() format string. Therefore, a _Static_assert() is
  * used instead to maintain the relationship with KSYM_NAME_LEN.
  */
-#define KSYM_NAME_LEN_BUFFER   512
+#define KSYM_NAME_LEN_BUFFER   2048
 _Static_assert(
        KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4,
        "Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN"

diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h
index efb6c3f..5a37ccb 100644 (file)
--- a/tools/include/linux/kallsyms.h
+++ b/tools/include/linux/kallsyms.h
@@ -6,7 +6,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 512
 
 struct module;
 

diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
index 93bf93a..d8ae4e9 100644 (file)
--- a/tools/lib/perf/include/perf/event.h
+++ b/tools/lib/perf/include/perf/event.h
@@ -97,7 +97,7 @@ struct perf_record_throttle {
 };
 
 #ifndef KSYM_NAME_LEN
-#define KSYM_NAME_LEN 256
+#define KSYM_NAME_LEN 512
 #endif
 
 struct perf_record_ksymbol {

diff --git a/tools/lib/symbol/kallsyms.h b/tools/lib/symbol/kallsyms.h
index 72ab987..542f9b0 100644 (file)
--- a/tools/lib/symbol/kallsyms.h
+++ b/tools/lib/symbol/kallsyms.h
@@ -7,7 +7,7 @@
 #include <linux/types.h>
 
 #ifndef KSYM_NAME_LEN
-#define KSYM_NAME_LEN 256
+#define KSYM_NAME_LEN 512
 #endif
 
 static inline u8 kallsyms2elf_binding(char type)