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SubjectRe: [PATCH 2/2] livepatch: Fix the bug if the function name is larger than KSYM_NAME_LEN-1
On Sun 2015-04-12 21:15:54, Minfei Huang wrote:
> For now, the kallsyms will only store the first (KSYM_NAME_LEN-1). The
> kallsyms name is same for the function which first (KSYM_NAME_LEN-1) is
> same, but the rest is not.
>
> Then function will never be patched, although function name and address
> are provided both. The reason caused this bug is livepatch cannt
> recognize the function name.
>
> Now, livepatch will verify the function name with first (KSYM_NAME_LEN-1)
> and address, if provided. Once they are matched, we can confirm that the
> patched function is found.

This patch kind of make sense for vmlinux addresses. But are there
functions with such a long names (>128 characters)? I hope not. They
would never fit 80 characters per-line.

In each case, it does not make sense for modules because we are
not able to find the symbol via old_addr.

Best Regards,
Petr

> Signed-off-by: Minfei Huang <minfei.huang@hotmail.com>
> ---
> kernel/livepatch/core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index ff42c29..eed719d 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -210,7 +210,7 @@ static int klp_verify_vmlinux_callback(void *data, const char *name,
> struct klp_verify_args *args = data;
>
> if (!mod &&
> - !strcmp(args->name, name) &&
> + !strncmp(args->name, name, KSYM_NAME_LEN-1) &&
> args->addr == addr)
> return 1;
>
> @@ -226,7 +226,7 @@ static int klp_verify_module_callback(void *data, const char *name,
> return 0;
>
> if (!strcmp(args->objname, mod->name) &&
> - !strcmp(args->name, name) &&
> + !strncmp(args->name, name, KSYM_NAME_LEN-1) &&
> args->addr == addr)
> return 1;
>
> --
> 2.2.2
>
> --
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