2023-06-29 10:53:06

by Michal Kubecek

Subject: [PATCH] objtool: initialize all of struct elf

Function elf_open_read() only zero initializes the initial part of
allocated struct elf; num_relocs member was recently added outside the
zeroed part so that it was left uninitialized, resulting in build failures
on some systems.

The partial initialization is a relic of times when struct elf had large
hash tables embedded. This is no longer the case so remove the trap and
initialize the whole structure instead.

Fixes: eb0481bbc4ce ("objtool: Fix reloc_hash size")
Signed-off-by: Michal Kubecek <[email protected]>
---
tools/objtool/elf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index d420b5d2e2b6..081befa4674b 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -1005,7 +1005,7 @@ struct elf *elf_open_read(const char *name, int flags)
perror("malloc");
return NULL;
}
- memset(elf, 0, offsetof(struct elf, sections));
+ memset(elf, 0, sizeof(*elf));

INIT_LIST_HEAD(&elf->sections);

--
2.41.0

2023-06-29 14:43:20

by Josh Poimboeuf

Subject: Re: [PATCH] objtool: initialize all of struct elf

On Thu, Jun 29, 2023 at 12:05:05PM +0200, Michal Kubecek wrote:
> Function elf_open_read() only zero initializes the initial part of
> allocated struct elf; num_relocs member was recently added outside the
> zeroed part so that it was left uninitialized, resulting in build failures
> on some systems.
>
> The partial initialization is a relic of times when struct elf had large
> hash tables embedded. This is no longer the case so remove the trap and
> initialize the whole structure instead.
>
> Fixes: eb0481bbc4ce ("objtool: Fix reloc_hash size")
> Signed-off-by: Michal Kubecek <[email protected]>
> ---
> tools/objtool/elf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
> index d420b5d2e2b6..081befa4674b 100644
> --- a/tools/objtool/elf.c
> +++ b/tools/objtool/elf.c
> @@ -1005,7 +1005,7 @@ struct elf *elf_open_read(const char *name, int flags)
> perror("malloc");
> return NULL;
> }
> - memset(elf, 0, offsetof(struct elf, sections));
> + memset(elf, 0, sizeof(*elf));
>
> INIT_LIST_HEAD(&elf->sections);

Thanks!

Acked-by: Josh Poimboeuf <[email protected]>

--
Josh

2023-07-10 08:28:25

by tip-bot2 for Jacob Pan

Subject: [tip: objtool/urgent] objtool: initialize all of struct elf

The following commit has been merged into the objtool/urgent branch of tip:

Commit-ID: 9f71fbcde2820f2af4658313e808cf1e579190a4
Gitweb: https://git.kernel.org/tip/9f71fbcde2820f2af4658313e808cf1e579190a4
Author: Michal Kubecek <[email protected]>
AuthorDate: Thu, 29 Jun 2023 12:05:05 +02:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Mon, 10 Jul 2023 09:52:28 +02:00

objtool: initialize all of struct elf

Function elf_open_read() only zero initializes the initial part of
allocated struct elf; num_relocs member was recently added outside the
zeroed part so that it was left uninitialized, resulting in build failures
on some systems.

The partial initialization is a relic of times when struct elf had large
hash tables embedded. This is no longer the case so remove the trap and
initialize the whole structure instead.

Fixes: eb0481bbc4ce ("objtool: Fix reloc_hash size")
Signed-off-by: Michal Kubecek <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
tools/objtool/elf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index d420b5d..081befa 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -1005,7 +1005,7 @@ struct elf *elf_open_read(const char *name, int flags)
perror("malloc");
return NULL;
}
- memset(elf, 0, offsetof(struct elf, sections));
+ memset(elf, 0, sizeof(*elf));

INIT_LIST_HEAD(&elf->sections);