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kallsyms: increase maximum kernel symbol length to 512

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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>
This commit is contained in:
Miguel Ojeda 2021-04-05 05:03:50 +02:00
parent 73bbb94466
commit b8a94bfb33
6 changed files with 8 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/kallsyms.h
View File

@ -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) + \

4
kernel/livepatch/core.c
View File

@ -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",

4
scripts/kallsyms.c
View File

@ -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"

2
tools/include/linux/kallsyms.h
View File

@ -6,7 +6,7 @@
#include <stdio.h>
#include <unistd.h>
#define KSYM_NAME_LEN 128
#define KSYM_NAME_LEN 512
struct module;

2
tools/lib/perf/include/perf/event.h
View File

@ -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 {

2
tools/lib/symbol/kallsyms.h
View File

@ -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)