* [PATCH] kprobes: Allow both @symbol_name and @addr to exist
@ 2022-03-13 3:21 Bang Li
2022-03-13 8:36 ` Masami Hiramatsu
0 siblings, 1 reply; 3+ messages in thread
From: Bang Li @ 2022-03-13 3:21 UTC (permalink / raw)
To: naveen.n.rao, anil.s.keshavamurthy, davem, mhiramat; +Cc: linux-kernel, Bang Li
If the address found by the @symbol_name is equal to the @addr, this case
should be considered a valid parameter combinations.
Example:
static struct kprobe kp = {
.symbol_name = "kernel_clone",
.addr = (kprobe_opcode_t*)kernel_clone,
};
Signed-off-by: Bang Li <libang.linuxer@gmail.com>
---
kernel/kprobes.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 94cab8c9ce56..70d4ed9e7dc7 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1497,13 +1497,19 @@ bool within_kprobe_blacklist(unsigned long addr)
static kprobe_opcode_t *_kprobe_addr(kprobe_opcode_t *addr,
const char *symbol_name, unsigned int offset)
{
- if ((symbol_name && addr) || (!symbol_name && !addr))
+ kprobe_opcode_t *symbol_addr;
+
+ if (!symbol_name && !addr)
goto invalid;
if (symbol_name) {
- addr = kprobe_lookup_name(symbol_name, offset);
- if (!addr)
+ symbol_addr = kprobe_lookup_name(symbol_name, offset);
+ if (!symbol_addr)
return ERR_PTR(-ENOENT);
+
+ if (addr && symbol_addr != addr)
+ goto invalid;
+ addr = symbol_addr;
}
addr = (kprobe_opcode_t *)(((char *)addr) + offset);
@@ -2062,8 +2068,7 @@ bool __weak arch_kprobe_on_func_entry(unsigned long offset)
* function entry address or not.
* This returns 0 if it is the function entry, or -EINVAL if it is not.
* And also it returns -ENOENT if it fails the symbol or address lookup.
- * Caller must pass @addr or @sym (either one must be NULL), or this
- * returns -EINVAL.
+ * Caller must pass @addr or @sym, or this returns -EINVAL.
*/
int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
{
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] kprobes: Allow both @symbol_name and @addr to exist
2022-03-13 3:21 [PATCH] kprobes: Allow both @symbol_name and @addr to exist Bang Li
@ 2022-03-13 8:36 ` Masami Hiramatsu
2022-03-15 13:56 ` 李棒
0 siblings, 1 reply; 3+ messages in thread
From: Masami Hiramatsu @ 2022-03-13 8:36 UTC (permalink / raw)
To: Bang Li; +Cc: naveen.n.rao, anil.s.keshavamurthy, davem, linux-kernel
On Sun, 13 Mar 2022 11:21:25 +0800
Bang Li <libang.linuxer@gmail.com> wrote:
> If the address found by the @symbol_name is equal to the @addr, this case
> should be considered a valid parameter combinations.
Could you tell me the reason why this is needed and use case?
I explictly made this case as an error, because I couldn't find
any good reason to support this case.
Thank you,
>
> Example:
>
> static struct kprobe kp = {
> .symbol_name = "kernel_clone",
> .addr = (kprobe_opcode_t*)kernel_clone,
> };
>
> Signed-off-by: Bang Li <libang.linuxer@gmail.com>
> ---
> kernel/kprobes.c | 15 ++++++++++-----
> 1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 94cab8c9ce56..70d4ed9e7dc7 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1497,13 +1497,19 @@ bool within_kprobe_blacklist(unsigned long addr)
> static kprobe_opcode_t *_kprobe_addr(kprobe_opcode_t *addr,
> const char *symbol_name, unsigned int offset)
> {
> - if ((symbol_name && addr) || (!symbol_name && !addr))
> + kprobe_opcode_t *symbol_addr;
> +
> + if (!symbol_name && !addr)
> goto invalid;
>
> if (symbol_name) {
> - addr = kprobe_lookup_name(symbol_name, offset);
> - if (!addr)
> + symbol_addr = kprobe_lookup_name(symbol_name, offset);
> + if (!symbol_addr)
> return ERR_PTR(-ENOENT);
> +
> + if (addr && symbol_addr != addr)
> + goto invalid;
> + addr = symbol_addr;
> }
>
> addr = (kprobe_opcode_t *)(((char *)addr) + offset);
> @@ -2062,8 +2068,7 @@ bool __weak arch_kprobe_on_func_entry(unsigned long offset)
> * function entry address or not.
> * This returns 0 if it is the function entry, or -EINVAL if it is not.
> * And also it returns -ENOENT if it fails the symbol or address lookup.
> - * Caller must pass @addr or @sym (either one must be NULL), or this
> - * returns -EINVAL.
> + * Caller must pass @addr or @sym, or this returns -EINVAL.
> */
> int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
> {
> --
> 2.25.1
>
--
Masami Hiramatsu <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] kprobes: Allow both @symbol_name and @addr to exist
2022-03-13 8:36 ` Masami Hiramatsu
@ 2022-03-15 13:56 ` 李棒
0 siblings, 0 replies; 3+ messages in thread
From: 李棒 @ 2022-03-15 13:56 UTC (permalink / raw)
To: Masami Hiramatsu; +Cc: naveen.n.rao, anil.s.keshavamurthy, davem, linux-kernel
On Sun, Mar 13, 2022 at 4:36 PM Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> On Sun, 13 Mar 2022 11:21:25 +0800
> Bang Li <libang.linuxer@gmail.com> wrote:
>
> > If the address found by the @symbol_name is equal to the @addr, this case
> > should be considered a valid parameter combinations.
>
> Could you tell me the reason why this is needed and use case?
> I explictly made this case as an error, because I couldn't find
> any good reason to support this case.
>
> Thank you,
>
I'm not sure if I need to change it this way, I just think it's more
comprehensive.
Thanks
> >
> > Example:
> >
> > static struct kprobe kp = {
> > .symbol_name = "kernel_clone",
> > .addr = (kprobe_opcode_t*)kernel_clone,
> > };
> >
> > Signed-off-by: Bang Li <libang.linuxer@gmail.com>
> > ---
> > kernel/kprobes.c | 15 ++++++++++-----
> > 1 file changed, 10 insertions(+), 5 deletions(-)
> >
> > diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> > index 94cab8c9ce56..70d4ed9e7dc7 100644
> > --- a/kernel/kprobes.c
> > +++ b/kernel/kprobes.c
> > @@ -1497,13 +1497,19 @@ bool within_kprobe_blacklist(unsigned long addr)
> > static kprobe_opcode_t *_kprobe_addr(kprobe_opcode_t *addr,
> > const char *symbol_name, unsigned int offset)
> > {
> > - if ((symbol_name && addr) || (!symbol_name && !addr))
> > + kprobe_opcode_t *symbol_addr;
> > +
> > + if (!symbol_name && !addr)
> > goto invalid;
> >
> > if (symbol_name) {
> > - addr = kprobe_lookup_name(symbol_name, offset);
> > - if (!addr)
> > + symbol_addr = kprobe_lookup_name(symbol_name, offset);
> > + if (!symbol_addr)
> > return ERR_PTR(-ENOENT);
> > +
> > + if (addr && symbol_addr != addr)
> > + goto invalid;
> > + addr = symbol_addr;
> > }
> >
> > addr = (kprobe_opcode_t *)(((char *)addr) + offset);
> > @@ -2062,8 +2068,7 @@ bool __weak arch_kprobe_on_func_entry(unsigned long offset)
> > * function entry address or not.
> > * This returns 0 if it is the function entry, or -EINVAL if it is not.
> > * And also it returns -ENOENT if it fails the symbol or address lookup.
> > - * Caller must pass @addr or @sym (either one must be NULL), or this
> > - * returns -EINVAL.
> > + * Caller must pass @addr or @sym, or this returns -EINVAL.
> > */
> > int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
> > {
> > --
> > 2.25.1
> >
>
>
> --
> Masami Hiramatsu <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-03-13 3:21 [PATCH] kprobes: Allow both @symbol_name and @addr to exist Bang Li
2022-03-13 8:36 ` Masami Hiramatsu
2022-03-15 13:56 ` 李棒
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