Re: [PATCH v4 01/19] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol

[Masami Hiramatsu]

On Mon, 5 Mar 2018 11:28:14 +0900
Namhyung Kim  wrote:

> Hi Masami,
> 
> On Fri, Mar 02, 2018 at 03:32:29PM +0900, Masami Hiramatsu wrote:
> > On Fri, 2 Mar 2018 13:49:51 +0900
> > Namhyung Kim  wrote:
> > 
> > > Hi Masami,
> > > 
> > > On Wed, Feb 28, 2018 at 12:19:53PM +0900, Masami Hiramatsu wrote:
> > > > In Documentation/trace/kprobetrace.txt, it says
> > > > 
> > > >  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data 
> > > > symbol)
> > > > 
> > > > However, the parser doesn't parse minus offset correctly, since
> > > > commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
> > > > unsigned") drops minus ("-") offset support for kprobe probe
> > > > address usage.
> > > > 
> > > > This fixes the traceprobe_split_symbol_offset() to parse minus
> > > > offset again with checking the offset range, and add a minus
> > > > offset check in kprobe probe address usage.
> > > 
> > > It now parses a minus offset but doesn't allow it, right?
> > 
> > No, split_symbol_offset() is used for 2 cases
> >  - kprobe-event probe point
> >  - kporbe-event symbol-based argument
> > 
> > Former one doesn't accept a minus offset, but latter accepts it.
> 
> Ah, ok then.
> 
> Acked-by: Namhyung Kim 

Thanks!!


-- 
Masami Hiramatsu 

Re: [PATCH v4 01/19] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol

[Masami Hiramatsu]

On Mon, 5 Mar 2018 11:28:14 +0900
Namhyung Kim  wrote:

> Hi Masami,
> 
> On Fri, Mar 02, 2018 at 03:32:29PM +0900, Masami Hiramatsu wrote:
> > On Fri, 2 Mar 2018 13:49:51 +0900
> > Namhyung Kim  wrote:
> > 
> > > Hi Masami,
> > > 
> > > On Wed, Feb 28, 2018 at 12:19:53PM +0900, Masami Hiramatsu wrote:
> > > > In Documentation/trace/kprobetrace.txt, it says
> > > > 
> > > >  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data 
> > > > symbol)
> > > > 
> > > > However, the parser doesn't parse minus offset correctly, since
> > > > commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
> > > > unsigned") drops minus ("-") offset support for kprobe probe
> > > > address usage.
> > > > 
> > > > This fixes the traceprobe_split_symbol_offset() to parse minus
> > > > offset again with checking the offset range, and add a minus
> > > > offset check in kprobe probe address usage.
> > > 
> > > It now parses a minus offset but doesn't allow it, right?
> > 
> > No, split_symbol_offset() is used for 2 cases
> >  - kprobe-event probe point
> >  - kporbe-event symbol-based argument
> > 
> > Former one doesn't accept a minus offset, but latter accepts it.
> 
> Ah, ok then.
> 
> Acked-by: Namhyung Kim 

Thanks!!


-- 
Masami Hiramatsu 

Re: [PATCH v4 01/19] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol

[Namhyung Kim]

Hi Masami,

On Fri, Mar 02, 2018 at 03:32:29PM +0900, Masami Hiramatsu wrote:
> On Fri, 2 Mar 2018 13:49:51 +0900
> Namhyung Kim  wrote:
> 
> > Hi Masami,
> > 
> > On Wed, Feb 28, 2018 at 12:19:53PM +0900, Masami Hiramatsu wrote:
> > > In Documentation/trace/kprobetrace.txt, it says
> > > 
> > >  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data 
> > > symbol)
> > > 
> > > However, the parser doesn't parse minus offset correctly, since
> > > commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
> > > unsigned") drops minus ("-") offset support for kprobe probe
> > > address usage.
> > > 
> > > This fixes the traceprobe_split_symbol_offset() to parse minus
> > > offset again with checking the offset range, and add a minus
> > > offset check in kprobe probe address usage.
> > 
> > It now parses a minus offset but doesn't allow it, right?
> 
> No, split_symbol_offset() is used for 2 cases
>  - kprobe-event probe point
>  - kporbe-event symbol-based argument
> 
> Former one doesn't accept a minus offset, but latter accepts it.

Ah, ok then.

Acked-by: Namhyung Kim 


> 
> (Frankly to say, I guess no one care about supporting minus offset :P)

:)

Thanks,
Namhyung

Re: [PATCH v4 01/19] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol

[Namhyung Kim]

Hi Masami,

On Fri, Mar 02, 2018 at 03:32:29PM +0900, Masami Hiramatsu wrote:
> On Fri, 2 Mar 2018 13:49:51 +0900
> Namhyung Kim  wrote:
> 
> > Hi Masami,
> > 
> > On Wed, Feb 28, 2018 at 12:19:53PM +0900, Masami Hiramatsu wrote:
> > > In Documentation/trace/kprobetrace.txt, it says
> > > 
> > >  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data 
> > > symbol)
> > > 
> > > However, the parser doesn't parse minus offset correctly, since
> > > commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
> > > unsigned") drops minus ("-") offset support for kprobe probe
> > > address usage.
> > > 
> > > This fixes the traceprobe_split_symbol_offset() to parse minus
> > > offset again with checking the offset range, and add a minus
> > > offset check in kprobe probe address usage.
> > 
> > It now parses a minus offset but doesn't allow it, right?
> 
> No, split_symbol_offset() is used for 2 cases
>  - kprobe-event probe point
>  - kporbe-event symbol-based argument
> 
> Former one doesn't accept a minus offset, but latter accepts it.

Ah, ok then.

Acked-by: Namhyung Kim 


> 
> (Frankly to say, I guess no one care about supporting minus offset :P)

:)

Thanks,
Namhyung

Re: [PATCH v4 01/19] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol

[Masami Hiramatsu]

On Fri, 2 Mar 2018 13:49:51 +0900
Namhyung Kim  wrote:

> Hi Masami,
> 
> On Wed, Feb 28, 2018 at 12:19:53PM +0900, Masami Hiramatsu wrote:
> > In Documentation/trace/kprobetrace.txt, it says
> > 
> >  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
> > 
> > However, the parser doesn't parse minus offset correctly, since
> > commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
> > unsigned") drops minus ("-") offset support for kprobe probe
> > address usage.
> > 
> > This fixes the traceprobe_split_symbol_offset() to parse minus
> > offset again with checking the offset range, and add a minus
> > offset check in kprobe probe address usage.
> 
> It now parses a minus offset but doesn't allow it, right?

No, split_symbol_offset() is used for 2 cases
 - kprobe-event probe point
 - kporbe-event symbol-based argument

Former one doesn't accept a minus offset, but latter accepts it.

(Frankly to say, I guess no one care about supporting minus offset :P)

Thanks,

> Then I still think it's better to fix the documentation.
> 
> 
> > 
> > Fixes: 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned")
> > Signed-off-by: Masami Hiramatsu 
> > ---
> >  Changes in v3:
> >   - Use kstrtol instead of kstrtoul. (Thanks Namhyung!)
> >  Changes in v4:
> >   - Fix to decode sign. (Thanks Namhyung!)
> >   - Fix to check UINT_MAX for kprobe offset.
> > ---
> >  kernel/trace/trace_kprobe.c |4 ++--
> >  kernel/trace/trace_probe.c  |8 +++-
> >  kernel/trace/trace_probe.h  |2 +-
> >  3 files changed, 6 insertions(+), 8 deletions(-)
> > 
> > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> > index 5ce9b8cf7be3..1cd3fb4d70f8 100644
> > --- a/kernel/trace/trace_kprobe.c
> > +++ b/kernel/trace/trace_kprobe.c
> > @@ -667,7 +667,7 @@ static int create_trace_kprobe(int argc, char **argv)
> > char *symbol = NULL, *event = NULL, *group = NULL;
> > int maxactive = 0;
> > char *arg;
> > -   unsigned long offset = 0;
> > +   long offset = 0;
> > void *addr = NULL;
> > char buf[MAX_EVENT_NAME_LEN];
> >  
> > @@ -755,7 +755,7 @@ static int create_trace_kprobe(int argc, char **argv)
> > symbol = argv[1];
> > /* TODO: support .init module functions */
> > ret = traceprobe_split_symbol_offset(symbol, );
> > -   if (ret) {
> > +   if (ret || offset < 0 || offset > UINT_MAX) {
> > pr_info("Failed to parse either an address or a 
> > symbol.\n");
> > return ret;
> 
> Wouldn't it be confusing if it returns 0 for an invalid input?
> 
> Thanks,
> Namhyung
> 
> 
> > }
> > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> > index d59357308677..daf54bda4dc8 100644
> > --- a/kernel/trace/trace_probe.c
> > +++ b/kernel/trace/trace_probe.c
> > @@ -320,7 +320,7 @@ static fetch_func_t get_fetch_size_function(const 
> > struct fetch_type *type,
> >  }
> >  
> >  /* Split symbol and offset. */
> > -int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
> > +int traceprobe_split_symbol_offset(char *symbol, long *offset)
> >  {
> > char *tmp;
> > int ret;
> > @@ -328,13 +328,11 @@ int traceprobe_split_symbol_offset(char *symbol, 
> > unsigned long *offset)
> > if (!offset)
> > return -EINVAL;
> >  
> > -   tmp = strchr(symbol, '+');
> > +   tmp = strpbrk(symbol, "+-");
> > if (tmp) {
> > -   /* skip sign because kstrtoul doesn't accept '+' */
> > -   ret = kstrtoul(tmp + 1, 0, offset);
> > +   ret = kstrtol(tmp, 0, offset);
> > if (ret)
> > return ret;
> > -
> > *tmp = '\0';
> > } else
> > *offset = 0;
> > diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> > index 0745f895f780..75daff22ccea 100644
> > --- a/kernel/trace/trace_probe.h
> > +++ b/kernel/trace/trace_probe.h
> > @@ -365,7 +365,7 @@ extern int traceprobe_conflict_field_name(const char 
> > *name,
> >  extern void traceprobe_update_arg(struct probe_arg *arg);
> >  extern void traceprobe_free_probe_arg(struct probe_arg *arg);
> >  
> > -extern int traceprobe_split_symbol_offset(char *symbol, unsigned long 
> > *offset);
> > +extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
> >  
> >  /* Sum up total data length for dynamic arraies (strings) */
> >  static nokprobe_inline int
> > 


-- 
Masami Hiramatsu 

Re: [PATCH v4 01/19] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol

[Masami Hiramatsu]

On Fri, 2 Mar 2018 13:49:51 +0900
Namhyung Kim  wrote:

> Hi Masami,
> 
> On Wed, Feb 28, 2018 at 12:19:53PM +0900, Masami Hiramatsu wrote:
> > In Documentation/trace/kprobetrace.txt, it says
> > 
> >  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
> > 
> > However, the parser doesn't parse minus offset correctly, since
> > commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
> > unsigned") drops minus ("-") offset support for kprobe probe
> > address usage.
> > 
> > This fixes the traceprobe_split_symbol_offset() to parse minus
> > offset again with checking the offset range, and add a minus
> > offset check in kprobe probe address usage.
> 
> It now parses a minus offset but doesn't allow it, right?

No, split_symbol_offset() is used for 2 cases
 - kprobe-event probe point
 - kporbe-event symbol-based argument

Former one doesn't accept a minus offset, but latter accepts it.

(Frankly to say, I guess no one care about supporting minus offset :P)

Thanks,

> Then I still think it's better to fix the documentation.
> 
> 
> > 
> > Fixes: 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned")
> > Signed-off-by: Masami Hiramatsu 
> > ---
> >  Changes in v3:
> >   - Use kstrtol instead of kstrtoul. (Thanks Namhyung!)
> >  Changes in v4:
> >   - Fix to decode sign. (Thanks Namhyung!)
> >   - Fix to check UINT_MAX for kprobe offset.
> > ---
> >  kernel/trace/trace_kprobe.c |4 ++--
> >  kernel/trace/trace_probe.c  |8 +++-
> >  kernel/trace/trace_probe.h  |2 +-
> >  3 files changed, 6 insertions(+), 8 deletions(-)
> > 
> > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> > index 5ce9b8cf7be3..1cd3fb4d70f8 100644
> > --- a/kernel/trace/trace_kprobe.c
> > +++ b/kernel/trace/trace_kprobe.c
> > @@ -667,7 +667,7 @@ static int create_trace_kprobe(int argc, char **argv)
> > char *symbol = NULL, *event = NULL, *group = NULL;
> > int maxactive = 0;
> > char *arg;
> > -   unsigned long offset = 0;
> > +   long offset = 0;
> > void *addr = NULL;
> > char buf[MAX_EVENT_NAME_LEN];
> >  
> > @@ -755,7 +755,7 @@ static int create_trace_kprobe(int argc, char **argv)
> > symbol = argv[1];
> > /* TODO: support .init module functions */
> > ret = traceprobe_split_symbol_offset(symbol, );
> > -   if (ret) {
> > +   if (ret || offset < 0 || offset > UINT_MAX) {
> > pr_info("Failed to parse either an address or a 
> > symbol.\n");
> > return ret;
> 
> Wouldn't it be confusing if it returns 0 for an invalid input?
> 
> Thanks,
> Namhyung
> 
> 
> > }
> > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> > index d59357308677..daf54bda4dc8 100644
> > --- a/kernel/trace/trace_probe.c
> > +++ b/kernel/trace/trace_probe.c
> > @@ -320,7 +320,7 @@ static fetch_func_t get_fetch_size_function(const 
> > struct fetch_type *type,
> >  }
> >  
> >  /* Split symbol and offset. */
> > -int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
> > +int traceprobe_split_symbol_offset(char *symbol, long *offset)
> >  {
> > char *tmp;
> > int ret;
> > @@ -328,13 +328,11 @@ int traceprobe_split_symbol_offset(char *symbol, 
> > unsigned long *offset)
> > if (!offset)
> > return -EINVAL;
> >  
> > -   tmp = strchr(symbol, '+');
> > +   tmp = strpbrk(symbol, "+-");
> > if (tmp) {
> > -   /* skip sign because kstrtoul doesn't accept '+' */
> > -   ret = kstrtoul(tmp + 1, 0, offset);
> > +   ret = kstrtol(tmp, 0, offset);
> > if (ret)
> > return ret;
> > -
> > *tmp = '\0';
> > } else
> > *offset = 0;
> > diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> > index 0745f895f780..75daff22ccea 100644
> > --- a/kernel/trace/trace_probe.h
> > +++ b/kernel/trace/trace_probe.h
> > @@ -365,7 +365,7 @@ extern int traceprobe_conflict_field_name(const char 
> > *name,
> >  extern void traceprobe_update_arg(struct probe_arg *arg);
> >  extern void traceprobe_free_probe_arg(struct probe_arg *arg);
> >  
> > -extern int traceprobe_split_symbol_offset(char *symbol, unsigned long 
> > *offset);
> > +extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
> >  
> >  /* Sum up total data length for dynamic arraies (strings) */
> >  static nokprobe_inline int
> > 


-- 
Masami Hiramatsu 

Re: [PATCH v4 01/19] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol

[Namhyung Kim]

Hi Masami,

On Wed, Feb 28, 2018 at 12:19:53PM +0900, Masami Hiramatsu wrote:
> In Documentation/trace/kprobetrace.txt, it says
> 
>  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
> 
> However, the parser doesn't parse minus offset correctly, since
> commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
> unsigned") drops minus ("-") offset support for kprobe probe
> address usage.
> 
> This fixes the traceprobe_split_symbol_offset() to parse minus
> offset again with checking the offset range, and add a minus
> offset check in kprobe probe address usage.

It now parses a minus offset but doesn't allow it, right?
Then I still think it's better to fix the documentation.


> 
> Fixes: 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned")
> Signed-off-by: Masami Hiramatsu 
> ---
>  Changes in v3:
>   - Use kstrtol instead of kstrtoul. (Thanks Namhyung!)
>  Changes in v4:
>   - Fix to decode sign. (Thanks Namhyung!)
>   - Fix to check UINT_MAX for kprobe offset.
> ---
>  kernel/trace/trace_kprobe.c |4 ++--
>  kernel/trace/trace_probe.c  |8 +++-
>  kernel/trace/trace_probe.h  |2 +-
>  3 files changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 5ce9b8cf7be3..1cd3fb4d70f8 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -667,7 +667,7 @@ static int create_trace_kprobe(int argc, char **argv)
>   char *symbol = NULL, *event = NULL, *group = NULL;
>   int maxactive = 0;
>   char *arg;
> - unsigned long offset = 0;
> + long offset = 0;
>   void *addr = NULL;
>   char buf[MAX_EVENT_NAME_LEN];
>  
> @@ -755,7 +755,7 @@ static int create_trace_kprobe(int argc, char **argv)
>   symbol = argv[1];
>   /* TODO: support .init module functions */
>   ret = traceprobe_split_symbol_offset(symbol, );
> - if (ret) {
> + if (ret || offset < 0 || offset > UINT_MAX) {
>   pr_info("Failed to parse either an address or a 
> symbol.\n");
>   return ret;

Wouldn't it be confusing if it returns 0 for an invalid input?

Thanks,
Namhyung


>   }
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index d59357308677..daf54bda4dc8 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -320,7 +320,7 @@ static fetch_func_t get_fetch_size_function(const struct 
> fetch_type *type,
>  }
>  
>  /* Split symbol and offset. */
> -int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
> +int traceprobe_split_symbol_offset(char *symbol, long *offset)
>  {
>   char *tmp;
>   int ret;
> @@ -328,13 +328,11 @@ int traceprobe_split_symbol_offset(char *symbol, 
> unsigned long *offset)
>   if (!offset)
>   return -EINVAL;
>  
> - tmp = strchr(symbol, '+');
> + tmp = strpbrk(symbol, "+-");
>   if (tmp) {
> - /* skip sign because kstrtoul doesn't accept '+' */
> - ret = kstrtoul(tmp + 1, 0, offset);
> + ret = kstrtol(tmp, 0, offset);
>   if (ret)
>   return ret;
> -
>   *tmp = '\0';
>   } else
>   *offset = 0;
> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> index 0745f895f780..75daff22ccea 100644
> --- a/kernel/trace/trace_probe.h
> +++ b/kernel/trace/trace_probe.h
> @@ -365,7 +365,7 @@ extern int traceprobe_conflict_field_name(const char 
> *name,
>  extern void traceprobe_update_arg(struct probe_arg *arg);
>  extern void traceprobe_free_probe_arg(struct probe_arg *arg);
>  
> -extern int traceprobe_split_symbol_offset(char *symbol, unsigned long 
> *offset);
> +extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
>  
>  /* Sum up total data length for dynamic arraies (strings) */
>  static nokprobe_inline int
> 

Re: [PATCH v4 01/19] [BUGFIX] tracing: probeevent: Fix to support minus offset from symbol

[Namhyung Kim]

Hi Masami,

On Wed, Feb 28, 2018 at 12:19:53PM +0900, Masami Hiramatsu wrote:
> In Documentation/trace/kprobetrace.txt, it says
> 
>  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
> 
> However, the parser doesn't parse minus offset correctly, since
> commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
> unsigned") drops minus ("-") offset support for kprobe probe
> address usage.
> 
> This fixes the traceprobe_split_symbol_offset() to parse minus
> offset again with checking the offset range, and add a minus
> offset check in kprobe probe address usage.

It now parses a minus offset but doesn't allow it, right?
Then I still think it's better to fix the documentation.


> 
> Fixes: 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned")
> Signed-off-by: Masami Hiramatsu 
> ---
>  Changes in v3:
>   - Use kstrtol instead of kstrtoul. (Thanks Namhyung!)
>  Changes in v4:
>   - Fix to decode sign. (Thanks Namhyung!)
>   - Fix to check UINT_MAX for kprobe offset.
> ---
>  kernel/trace/trace_kprobe.c |4 ++--
>  kernel/trace/trace_probe.c  |8 +++-
>  kernel/trace/trace_probe.h  |2 +-
>  3 files changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 5ce9b8cf7be3..1cd3fb4d70f8 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -667,7 +667,7 @@ static int create_trace_kprobe(int argc, char **argv)
>   char *symbol = NULL, *event = NULL, *group = NULL;
>   int maxactive = 0;
>   char *arg;
> - unsigned long offset = 0;
> + long offset = 0;
>   void *addr = NULL;
>   char buf[MAX_EVENT_NAME_LEN];
>  
> @@ -755,7 +755,7 @@ static int create_trace_kprobe(int argc, char **argv)
>   symbol = argv[1];
>   /* TODO: support .init module functions */
>   ret = traceprobe_split_symbol_offset(symbol, );
> - if (ret) {
> + if (ret || offset < 0 || offset > UINT_MAX) {
>   pr_info("Failed to parse either an address or a 
> symbol.\n");
>   return ret;

Wouldn't it be confusing if it returns 0 for an invalid input?

Thanks,
Namhyung


>   }
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index d59357308677..daf54bda4dc8 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -320,7 +320,7 @@ static fetch_func_t get_fetch_size_function(const struct 
> fetch_type *type,
>  }
>  
>  /* Split symbol and offset. */
> -int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
> +int traceprobe_split_symbol_offset(char *symbol, long *offset)
>  {
>   char *tmp;
>   int ret;
> @@ -328,13 +328,11 @@ int traceprobe_split_symbol_offset(char *symbol, 
> unsigned long *offset)
>   if (!offset)
>   return -EINVAL;
>  
> - tmp = strchr(symbol, '+');
> + tmp = strpbrk(symbol, "+-");
>   if (tmp) {
> - /* skip sign because kstrtoul doesn't accept '+' */
> - ret = kstrtoul(tmp + 1, 0, offset);
> + ret = kstrtol(tmp, 0, offset);
>   if (ret)
>   return ret;
> -
>   *tmp = '\0';
>   } else
>   *offset = 0;
> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> index 0745f895f780..75daff22ccea 100644
> --- a/kernel/trace/trace_probe.h
> +++ b/kernel/trace/trace_probe.h
> @@ -365,7 +365,7 @@ extern int traceprobe_conflict_field_name(const char 
> *name,
>  extern void traceprobe_update_arg(struct probe_arg *arg);
>  extern void traceprobe_free_probe_arg(struct probe_arg *arg);
>  
> -extern int traceprobe_split_symbol_offset(char *symbol, unsigned long 
> *offset);
> +extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
>  
>  /* Sum up total data length for dynamic arraies (strings) */
>  static nokprobe_inline int
>