From: Nick Desaulniers <ndesaulniers@google.com>
To: Miguel Ojeda <ojeda@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
rust-for-linux@vger.kernel.org,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Linux Doc Mailing List <linux-doc@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Alex Gaynor <alex.gaynor@gmail.com>,
Geoffrey Thomas <geofft@ldpreload.com>,
Finn Behrens <me@kloenk.de>,
Adam Bratschi-Kaye <ark.email@gmail.com>,
Wedson Almeida Filho <wedsonaf@google.com>
Subject: Re: [PATCH 02/13] kallsyms: Increase maximum kernel symbol length to 512
Date: Wed, 14 Apr 2021 16:48:31 -0700 [thread overview]
Message-ID: <CAKwvOdk+Wya_mhVMPiiv1MVwCGX4DTZ2tX=AOm1-XGOYN5yMZg@mail.gmail.com> (raw)
In-Reply-To: <20210414184604.23473-3-ojeda@kernel.org>
On Wed, Apr 14, 2021 at 11:48 AM <ojeda@kernel.org> wrote:
>
> From: Miguel Ojeda <ojeda@kernel.org>
>
> Rust symbols can become quite long due to namespacing introduced
> by modules, types, traits, generics, etc. For instance, for:
>
> 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.
What are the implications of this change for someone not using Rust?
Does it change the binary size of vmlinux for a defconfig build, for
example?
>
> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
> Co-developed-by: Geoffrey Thomas <geofft@ldpreload.com>
> Signed-off-by: Geoffrey Thomas <geofft@ldpreload.com>
> Co-developed-by: Finn Behrens <me@kloenk.de>
> Signed-off-by: Finn Behrens <me@kloenk.de>
> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com>
> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> include/linux/kallsyms.h | 2 +-
> kernel/livepatch/core.c | 4 ++--
> scripts/kallsyms.c | 2 +-
> tools/include/linux/kallsyms.h | 2 +-
> tools/include/linux/lockdep.h | 2 +-
> tools/lib/perf/include/perf/event.h | 2 +-
> tools/lib/symbol/kallsyms.h | 2 +-
> 7 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
> index 465060acc981..5cdc6903abca 100644
> --- a/include/linux/kallsyms.h
> +++ b/include/linux/kallsyms.h
> @@ -14,7 +14,7 @@
>
> #include <asm/sections.h>
>
> -#define KSYM_NAME_LEN 128
> +#define KSYM_NAME_LEN 512
> #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
> 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
>
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index 335d988bd811..73874e5edfda 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -213,7 +213,7 @@ static int klp_resolve_symbols(Elf64_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(Elf64_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 bcdabee13aab..9bab5f55ade3 100644
> --- a/scripts/kallsyms.c
> +++ b/scripts/kallsyms.c
> @@ -27,7 +27,7 @@
>
> #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
>
> -#define KSYM_NAME_LEN 128
> +#define KSYM_NAME_LEN 512
>
> struct sym_entry {
> unsigned long long addr;
> diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h
> index efb6c3f5f2a9..5a37ccbec54f 100644
> --- 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/include/linux/lockdep.h b/tools/include/linux/lockdep.h
> index e56997288f2b..d9c163f3ab24 100644
> --- a/tools/include/linux/lockdep.h
> +++ b/tools/include/linux/lockdep.h
> @@ -47,7 +47,7 @@ static inline int debug_locks_off(void)
>
> #define task_pid_nr(tsk) ((tsk)->pid)
>
> -#define KSYM_NAME_LEN 128
> +#define KSYM_NAME_LEN 512
> #define printk(...) dprintf(STDOUT_FILENO, __VA_ARGS__)
> #define pr_err(format, ...) fprintf (stderr, format, ## __VA_ARGS__)
> #define pr_warn pr_err
> diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
> index d82054225fcc..f5c40325b441 100644
> --- a/tools/lib/perf/include/perf/event.h
> +++ b/tools/lib/perf/include/perf/event.h
> @@ -93,7 +93,7 @@ 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 72ab9870454b..542f9b059c3b 100644
> --- 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)
> --
> 2.17.1
>
--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2021-04-14 23:48 UTC|newest]
Thread overview: 201+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 18:45 [PATCH 00/13] [RFC] Rust support ojeda
2021-04-14 18:45 ` [PATCH 01/13] kallsyms: Support "big" kernel symbols (2-byte lengths) ojeda
2021-04-14 19:44 ` Matthew Wilcox
2021-04-14 19:59 ` Miguel Ojeda
2021-04-14 18:45 ` [PATCH 02/13] kallsyms: Increase maximum kernel symbol length to 512 ojeda
2021-04-14 23:48 ` Nick Desaulniers [this message]
2021-04-14 18:45 ` [PATCH 03/13] Makefile: Generate CLANG_FLAGS even in GCC builds ojeda
2021-04-14 18:59 ` Nathan Chancellor
2021-04-15 10:18 ` Miguel Ojeda
2021-04-14 23:46 ` Nick Desaulniers
2021-04-15 0:47 ` Miguel Ojeda
2021-04-14 18:45 ` [PATCH 04/13] Kbuild: Rust support ojeda
2021-04-14 23:19 ` Nick Desaulniers
2021-04-15 0:43 ` Miguel Ojeda
2021-04-15 18:03 ` Nick Desaulniers
2021-04-16 12:23 ` Miguel Ojeda
2021-04-17 19:35 ` Masahiro Yamada
2021-04-16 13:38 ` Peter Zijlstra
2021-04-16 17:05 ` Linus Torvalds
2021-04-16 17:47 ` Miguel Ojeda
2021-04-16 18:09 ` Al Viro
2021-04-16 18:57 ` Miguel Ojeda
2021-04-16 20:22 ` Willy Tarreau
2021-04-16 20:34 ` Connor Kuehl
2021-04-16 20:58 ` Willy Tarreau
2021-04-16 21:39 ` Miguel Ojeda
2021-04-16 22:04 ` Willy Tarreau
2021-04-16 22:45 ` Al Viro
2021-04-16 23:46 ` Miguel Ojeda
2021-04-17 4:24 ` Willy Tarreau
2021-04-17 15:38 ` Miguel Ojeda
2021-04-16 21:19 ` Miguel Ojeda
2021-04-16 17:34 ` Miguel Ojeda
2021-04-19 19:58 ` David Sterba
2021-04-19 20:17 ` Matthew Wilcox
2021-04-19 21:03 ` Miguel Ojeda
2021-04-19 20:54 ` Miguel Ojeda
2021-04-14 18:45 ` [PATCH 05/13] Rust: Compiler builtins crate ojeda
2021-04-14 19:19 ` Linus Torvalds
2021-04-14 19:34 ` Miguel Ojeda
2021-04-14 18:45 ` [PATCH 06/13] Rust: Module crate ojeda
2021-04-14 18:45 ` [PATCH 07/13] Rust: Kernel crate ojeda
2021-04-14 19:31 ` Linus Torvalds
2021-04-14 19:50 ` Miguel Ojeda
2021-04-14 18:45 ` [PATCH 08/13] Rust: Export generated symbols ojeda
2021-04-14 18:46 ` [PATCH 09/13] Samples: Rust examples ojeda
2021-04-14 19:34 ` Linus Torvalds
2021-04-14 19:42 ` Miguel Ojeda
2021-04-14 19:49 ` Matthew Wilcox
2021-04-16 11:46 ` Andrej Shadura
2021-04-14 23:24 ` Nick Desaulniers
2021-04-15 7:10 ` Greg Kroah-Hartman
2021-04-15 7:39 ` Nick Desaulniers
2021-04-15 12:42 ` Miguel Ojeda
2021-04-16 13:07 ` Sven Van Asbroeck
2021-04-16 13:20 ` Greg Kroah-Hartman
2021-04-14 18:46 ` [PATCH 10/13] Documentation: Rust general information ojeda
2021-04-14 22:17 ` Nick Desaulniers
2021-04-14 23:34 ` Miguel Ojeda
2021-04-14 18:46 ` [PATCH 11/13] MAINTAINERS: Rust ojeda
2021-04-14 21:55 ` Nick Desaulniers
2021-04-14 22:02 ` Miguel Ojeda
2021-04-14 22:36 ` Nick Desaulniers
2021-04-14 18:46 ` [PATCH 12/13] Rust: add abstractions for Binder (WIP) ojeda
2021-04-14 18:46 ` [PATCH 13/13] Android: Binder IPC in Rust (WIP) ojeda
2021-04-14 19:44 ` [PATCH 00/13] [RFC] Rust support Linus Torvalds
2021-04-14 20:20 ` Miguel Ojeda
2021-04-15 1:38 ` Kees Cook
2021-04-15 8:26 ` David Laight
2021-04-15 18:08 ` Kees Cook
2021-04-15 12:39 ` Miguel Ojeda
2021-04-14 20:09 ` Matthew Wilcox
2021-04-14 20:21 ` Linus Torvalds
2021-04-14 20:35 ` Josh Triplett
2021-04-14 22:08 ` David Laight
2021-04-14 20:29 ` Miguel Ojeda
2021-04-18 15:31 ` Wedson Almeida Filho
2021-04-15 0:22 ` Nick Desaulniers
2021-04-15 10:05 ` Miguel Ojeda
2021-04-15 18:58 ` Peter Zijlstra
2021-04-16 2:22 ` Wedson Almeida Filho
2021-04-16 4:25 ` Al Viro
2021-04-16 5:02 ` Wedson Almeida Filho
2021-04-16 5:39 ` Paul Zimmerman
2021-04-16 7:46 ` Peter Zijlstra
2021-04-16 7:09 ` Peter Zijlstra
2021-04-17 5:23 ` comex
2021-04-17 12:46 ` David Laight
2021-04-17 14:51 ` Paolo Bonzini
2021-04-19 7:32 ` Peter Zijlstra
2021-04-19 7:53 ` Paolo Bonzini
2021-04-19 8:26 ` Peter Zijlstra
2021-04-19 8:35 ` Peter Zijlstra
2021-04-19 9:02 ` Paolo Bonzini
2021-04-19 9:36 ` Peter Zijlstra
2021-04-19 9:40 ` Paolo Bonzini
2021-04-19 11:01 ` Will Deacon
2021-04-19 17:14 ` Linus Torvalds
2021-04-19 18:38 ` Paolo Bonzini
2021-04-19 18:50 ` Linus Torvalds
2021-04-22 10:03 ` Linus Walleij
2021-04-22 14:09 ` David Laight
2021-04-22 15:24 ` Wedson Almeida Filho
2021-04-26 0:18 ` Linus Walleij
2021-04-26 14:26 ` Miguel Ojeda
2021-04-26 14:40 ` Wedson Almeida Filho
2021-04-26 16:03 ` Miguel Ojeda
2021-04-27 10:54 ` Linus Walleij
2021-04-27 11:13 ` Robin Randhawa
2021-04-29 1:52 ` Wedson Almeida Filho
2021-04-26 18:01 ` Miguel Ojeda
2021-04-22 21:28 ` Miguel Ojeda
2021-04-26 0:31 ` Linus Walleij
2021-04-26 18:18 ` Miguel Ojeda
2021-04-27 11:13 ` Linus Walleij
2021-04-28 2:51 ` Kyle Strand
2021-04-28 3:10 ` Miguel Ojeda
2021-05-04 21:21 ` Linus Walleij
2021-05-04 23:30 ` Miguel Ojeda
2021-05-05 11:34 ` Linus Walleij
2021-05-05 14:17 ` Miguel Ojeda
2021-05-05 15:13 ` Enrico Weigelt, metux IT consult
2021-05-06 12:47 ` Linus Walleij
2021-05-07 18:23 ` Miguel Ojeda
2021-04-16 4:27 ` Boqun Feng
2021-04-16 6:04 ` Nick Desaulniers
2021-04-16 18:47 ` Paul E. McKenney
2021-04-19 20:35 ` Nick Desaulniers
2021-04-19 21:37 ` Paul E. McKenney
2021-04-19 22:03 ` Miguel Ojeda
2021-04-16 20:48 ` Josh Triplett
2021-04-16 8:16 ` Michal Kubecek
2021-04-16 9:29 ` Willy Tarreau
2021-04-16 11:24 ` Peter Zijlstra
2021-04-16 13:07 ` Wedson Almeida Filho
2021-04-16 14:19 ` Peter Zijlstra
2021-04-16 15:04 ` Miguel Ojeda
2021-04-16 15:43 ` Peter Zijlstra
2021-04-16 16:21 ` Miguel Ojeda
2021-04-16 15:33 ` Wedson Almeida Filho
2021-04-16 16:14 ` Willy Tarreau
2021-04-16 17:10 ` Miguel Ojeda
2021-04-16 17:18 ` Peter Zijlstra
2021-04-16 18:08 ` Matthew Wilcox
2021-04-17 11:17 ` Peter Zijlstra
2021-04-17 11:46 ` Willy Tarreau
2021-04-17 14:24 ` Peter Zijlstra
2021-04-17 14:36 ` Willy Tarreau
2021-04-17 13:46 ` David Laight
2021-04-16 17:37 ` Willy Tarreau
2021-04-16 17:46 ` Connor Kuehl
2021-04-20 0:24 ` Nick Desaulniers
2021-04-20 3:47 ` Willy Tarreau
2021-04-20 5:56 ` Greg Kroah-Hartman
2021-04-20 6:16 ` Willy Tarreau
2021-04-29 15:38 ` peter enderborg
2021-04-17 13:53 ` Wedson Almeida Filho
2021-04-17 14:21 ` Willy Tarreau
2021-04-17 15:23 ` Miguel Ojeda
2021-04-18 15:51 ` Wedson Almeida Filho
2021-04-17 12:41 ` David Laight
2021-04-17 13:01 ` Wedson Almeida Filho
2021-04-16 15:03 ` Matthew Wilcox
2021-04-17 13:29 ` Wedson Almeida Filho
2021-04-16 15:58 ` Theodore Ts'o
2021-04-16 16:21 ` Wedson Almeida Filho
2021-04-17 15:11 ` Paolo Bonzini
2021-04-16 14:21 ` Miguel Ojeda
2021-04-17 20:42 ` Richard Weinberger
2021-04-28 18:34 ` Mariusz Ceier
2021-04-28 20:25 ` Nick Desaulniers
2021-04-28 21:21 ` David Laight
2021-04-29 11:14 ` Kajetan Puchalski
2021-04-29 11:25 ` Kajetan Puchalski
2021-04-29 14:06 ` Mariusz Ceier
2021-04-29 14:13 ` Sven Van Asbroeck
2021-04-29 14:26 ` Willy Tarreau
2021-04-29 15:06 ` Al Viro
2021-04-29 16:09 ` Mariusz Ceier
2021-04-30 6:39 ` Thomas Schoebel-Theuer
2021-04-30 8:30 ` David Laight
2021-05-05 13:58 ` Enrico Weigelt, metux IT consult
2021-05-05 14:41 ` Miguel Ojeda
2022-06-20 15:11 ` Olliver Schinagl
2022-06-27 17:44 ` Miguel Ojeda
2022-07-18 6:56 ` Olliver Schinagl
2022-07-20 19:23 ` Miguel Ojeda
2022-07-20 20:21 ` Nicolas Pitre
2022-07-27 7:47 ` Olliver Schinagl
2022-07-27 13:32 ` Nicolas Pitre
2022-07-27 8:05 ` Olliver Schinagl
2022-07-28 10:21 ` Gary Guo
2022-07-28 12:09 ` Greg Kroah-Hartman
2022-07-28 12:28 ` Gary Guo
2022-07-28 20:45 ` Olliver Schinagl
2022-07-29 8:04 ` Greg Kroah-Hartman
2022-07-28 20:43 ` Olliver Schinagl
2022-10-15 14:16 ` Olliver Schinagl
2022-10-16 1:44 ` Bagas Sanjaya
2022-10-16 1:50 ` Bagas Sanjaya
2022-10-16 13:23 ` Josh Triplett
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