Sorry for the noise,
plz add these Acked-by and Signed-off-by:
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Signed-off-by: Jianyu Zhan <nasa4836@xxxxxxxxx>
Thanks,
Jianyu Zhan
On Tue, Jul 29, 2014 at 8:47 PM, Jianyu Zhan <nasa4836@xxxxxxxxx> wrote:
> Hi, Ingo,
>
> Here is the new patch with typo fixed.
>
> Thanks.
>
> ---8<---
>
> Currently, if user specifies both symbol name and address, we just
> bail out.
>
> This might be too rude. This patch makes it give more tolerance.
> If both are specified, check address first, if the symbol found
> does not match the one user specify, print a waring. If not found,
> return -ENOENT, because some symbols might have muplitple instances,
> we don't bother to check symbol name.
> ---
> Documentation/kprobes.txt | 4 +++-
> kernel/kprobes.c | 32 +++++++++++++++++++++++++++++---
> 2 files changed, 32 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt
> index 4bbeca8..663b5ad 100644
> --- a/Documentation/kprobes.txt
> +++ b/Documentation/kprobes.txt
> @@ -358,7 +358,9 @@ to install a probepoint is known. This field is used to calculate the
> probepoint.
>
> 3. Specify either the kprobe "symbol_name" OR the "addr". If both are
> -specified, kprobe registration will fail with -EINVAL.
> +specified, only check "addr", because some symbols might have multiple
> +instances. If neither is specified, kprobe registration will fail
> +with -EINVAL.
>
> 4. With CISC architectures (such as i386 and x86_64), the kprobes code
> does not validate if the kprobe.addr is at an instruction boundary.
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 734e9a7..9768608 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1358,15 +1358,41 @@ static bool within_kprobe_blacklist(unsigned long addr)
> static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
> {
> kprobe_opcode_t *addr = p->addr;
> + char namebuf[KSYM_NAME_LEN];
> + const char *sym_name = NULL;
> + unsigned long offset;
>
> - if ((p->symbol_name && p->addr) ||
> - (!p->symbol_name && !p->addr))
> + if (!p->symbol_name && !p->addr)
> goto invalid;
>
> - if (p->symbol_name) {
> + /*
> + * Some symbols might have multiple instances,
> + * so if both are specified, only check address.
> + */
> + if (unlikely(p->addr && p->symbol_name)) {
> + sym_name = kallsyms_lookup((unsigned long)(p->addr),
> + NULL, &offset, NULL, namebuf);
> + if (!sym_name)
> + return ERR_PTR(-ENOENT);
> +
> + if (strncmp(sym_name, p->symbol_name, KSYM_NAME_LEN)
> + || offset != p->offset) {
> + pr_err("Incorrect symbol or offset, should be "
> + "symbol=%s, offset=%ld.\n", sym_name, offset);
> + goto invalid;
> + }
> + } else if (p->symbol_name) {
> + /* Only symbol case */
> kprobe_lookup_name(p->symbol_name, addr);
> if (!addr)
> return ERR_PTR(-ENOENT);
> + } else {
> + /*
> + * Only address case.
> + * Since we later will do a sanity check of the
> + * address range in check_kprobe_address_safe(),
> + * do nothing here.
> + */
> }
>
> addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
> --
> 2.0.0
>
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