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* [PATCH] tracing/x86: fix trace event registration for syscalls without arguments
@ 2020-04-08 18:13 Konstantin Khlebnikov
  2020-04-27 13:16 ` Konstantin Khlebnikov
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Konstantin Khlebnikov @ 2020-04-08 18:13 UTC (permalink / raw)
  To: Brian Gerst, linux-kernel
  Cc: Thomas Gleixner, Dominik Brodowski, Andy Lutomirski

Syscalls without arguments now has no ABI subs, instead of that macro
SYSCALL_DEFINE0() defines __abi_sys_name as aliase to __do_sys_name.

As a result in find_syscall_meta() kallsyms_lookup() returns
"__do_sys_name" which does not match with declared trace event.

Also see commit 1c758a2202a6 ("tracing/x86: Update syscall trace events
to handle new prefixed syscall func names")

Fixes: d2b5de495ee9 ("x86/entry: Refactor SYSCALL_DEFINE0 macros")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
 arch/x86/include/asm/ftrace.h |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 85be2f506272..70b96cae5b42 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -61,11 +61,12 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name
 {
 	/*
 	 * Compare the symbol name with the system call name. Skip the
-	 * "__x64_sys", "__ia32_sys" or simple "sys" prefix.
+	 * "__x64_sys", "__ia32_sys", "__do_sys" or simple "sys" prefix.
 	 */
 	return !strcmp(sym + 3, name + 3) ||
 		(!strncmp(sym, "__x64_", 6) && !strcmp(sym + 9, name + 3)) ||
-		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3));
+		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3)) ||
+		(!strncmp(sym, "__do_sys", 8) && !strcmp(sym + 8, name + 3));
 }
 
 #ifndef COMPILE_OFFSETS


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] tracing/x86: fix trace event registration for syscalls without arguments
  2020-04-08 18:13 [PATCH] tracing/x86: fix trace event registration for syscalls without arguments Konstantin Khlebnikov
@ 2020-04-27 13:16 ` Konstantin Khlebnikov
  2020-04-27 19:13   ` Steven Rostedt
  2020-04-27 14:44 ` Thomas Gleixner
  2020-05-01 18:22 ` [tip: x86/urgent] ftrace/x86: Fix " tip-bot2 for Konstantin Khlebnikov
  2 siblings, 1 reply; 6+ messages in thread
From: Konstantin Khlebnikov @ 2020-04-27 13:16 UTC (permalink / raw)
  To: Brian Gerst, linux-kernel
  Cc: Thomas Gleixner, Dominik Brodowski, Andy Lutomirski,
	Steven Rostedt, Ingo Molnar

Bump, bug still present in 5.7.0-rc3

root@kernel0:~# uname -r
5.7.0-rc3-test

root@kernel0:~# ls -d /sys/kernel/tracing/events/syscalls/sys_enter_{sync,fsync}
ls: cannot access '/sys/kernel/tracing/events/syscalls/sys_enter_sync': No such file or directory
/sys/kernel/tracing/events/syscalls/sys_enter_fsync

On 08/04/2020 21.13, Konstantin Khlebnikov wrote:
> Syscalls without arguments now has no ABI subs, instead of that macro
> SYSCALL_DEFINE0() defines __abi_sys_name as aliase to __do_sys_name.
> 
> As a result in find_syscall_meta() kallsyms_lookup() returns
> "__do_sys_name" which does not match with declared trace event.
> 
> Also see commit 1c758a2202a6 ("tracing/x86: Update syscall trace events
> to handle new prefixed syscall func names")
> 
> Fixes: d2b5de495ee9 ("x86/entry: Refactor SYSCALL_DEFINE0 macros")
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
> ---
>   arch/x86/include/asm/ftrace.h |    5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
> index 85be2f506272..70b96cae5b42 100644
> --- a/arch/x86/include/asm/ftrace.h
> +++ b/arch/x86/include/asm/ftrace.h
> @@ -61,11 +61,12 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name
>   {
>   	/*
>   	 * Compare the symbol name with the system call name. Skip the
> -	 * "__x64_sys", "__ia32_sys" or simple "sys" prefix.
> +	 * "__x64_sys", "__ia32_sys", "__do_sys" or simple "sys" prefix.
>   	 */
>   	return !strcmp(sym + 3, name + 3) ||
>   		(!strncmp(sym, "__x64_", 6) && !strcmp(sym + 9, name + 3)) ||
> -		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3));
> +		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3)) ||
> +		(!strncmp(sym, "__do_sys", 8) && !strcmp(sym + 8, name + 3));
>   }
>   
>   #ifndef COMPILE_OFFSETS
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] tracing/x86: fix trace event registration for syscalls without arguments
  2020-04-08 18:13 [PATCH] tracing/x86: fix trace event registration for syscalls without arguments Konstantin Khlebnikov
  2020-04-27 13:16 ` Konstantin Khlebnikov
@ 2020-04-27 14:44 ` Thomas Gleixner
  2020-04-27 14:55   ` Konstantin Khlebnikov
  2020-05-01 18:22 ` [tip: x86/urgent] ftrace/x86: Fix " tip-bot2 for Konstantin Khlebnikov
  2 siblings, 1 reply; 6+ messages in thread
From: Thomas Gleixner @ 2020-04-27 14:44 UTC (permalink / raw)
  To: Konstantin Khlebnikov, Brian Gerst, linux-kernel
  Cc: Dominik Brodowski, Andy Lutomirski

Konstantin Khlebnikov <khlebnikov@yandex-team.ru> writes:

> Syscalls without arguments now has no ABI subs, instead of that macro

What is 'ABI subs'? 

> SYSCALL_DEFINE0() defines __abi_sys_name as aliase to __do_sys_name.
>
> As a result in find_syscall_meta() kallsyms_lookup() returns
> "__do_sys_name" which does not match with declared trace event.
>
> Also see commit 1c758a2202a6 ("tracing/x86: Update syscall trace events
> to handle new prefixed syscall func names")
>
> Fixes: d2b5de495ee9 ("x86/entry: Refactor SYSCALL_DEFINE0 macros")
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
> ---
>  arch/x86/include/asm/ftrace.h |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
> index 85be2f506272..70b96cae5b42 100644
> --- a/arch/x86/include/asm/ftrace.h
> +++ b/arch/x86/include/asm/ftrace.h
> @@ -61,11 +61,12 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name
>  {
>  	/*
>  	 * Compare the symbol name with the system call name. Skip the
> -	 * "__x64_sys", "__ia32_sys" or simple "sys" prefix.
> +	 * "__x64_sys", "__ia32_sys", "__do_sys" or simple "sys" prefix.
>  	 */
>  	return !strcmp(sym + 3, name + 3) ||
>  		(!strncmp(sym, "__x64_", 6) && !strcmp(sym + 9, name + 3)) ||
> -		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3));
> +		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3)) ||
> +		(!strncmp(sym, "__do_sys", 8) && !strcmp(sym + 8, name + 3));
>  }
>  
>  #ifndef COMPILE_OFFSETS

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] tracing/x86: fix trace event registration for syscalls without arguments
  2020-04-27 14:44 ` Thomas Gleixner
@ 2020-04-27 14:55   ` Konstantin Khlebnikov
  0 siblings, 0 replies; 6+ messages in thread
From: Konstantin Khlebnikov @ 2020-04-27 14:55 UTC (permalink / raw)
  To: Thomas Gleixner, Brian Gerst, linux-kernel
  Cc: Dominik Brodowski, Andy Lutomirski


On 27/04/2020 17.44, Thomas Gleixner wrote:
> Konstantin Khlebnikov <khlebnikov@yandex-team.ru> writes:
> 
>> Syscalls without arguments now has no ABI subs, instead of that macro
> 
> What is 'ABI subs'?

typo. ABI stubs

That commmit d2b5de495ee9 ("x86/entry: Refactor SYSCALL_DEFINE0 macros")

replaced usual wrapper

long __x64_syscall()
{	
	return __do_sys_syscall();
}

with alias

long __x64_syscall() __alias__(__do_sys_syscall);

And now symbol lookup for entry point return "__do_sys_syscall"
rather than "__x64_syscall" and ftrace magic cannot determine
syscall number for entry point and vise versa.

> 
>> SYSCALL_DEFINE0() defines __abi_sys_name as aliase to __do_sys_name.
>>
>> As a result in find_syscall_meta() kallsyms_lookup() returns
>> "__do_sys_name" which does not match with declared trace event.
>>
>> Also see commit 1c758a2202a6 ("tracing/x86: Update syscall trace events
>> to handle new prefixed syscall func names")
>>
>> Fixes: d2b5de495ee9 ("x86/entry: Refactor SYSCALL_DEFINE0 macros")
>> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
>> ---
>>   arch/x86/include/asm/ftrace.h |    5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
>> index 85be2f506272..70b96cae5b42 100644
>> --- a/arch/x86/include/asm/ftrace.h
>> +++ b/arch/x86/include/asm/ftrace.h
>> @@ -61,11 +61,12 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name
>>   {
>>   	/*
>>   	 * Compare the symbol name with the system call name. Skip the
>> -	 * "__x64_sys", "__ia32_sys" or simple "sys" prefix.
>> +	 * "__x64_sys", "__ia32_sys", "__do_sys" or simple "sys" prefix.
>>   	 */
>>   	return !strcmp(sym + 3, name + 3) ||
>>   		(!strncmp(sym, "__x64_", 6) && !strcmp(sym + 9, name + 3)) ||
>> -		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3));
>> +		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3)) ||
>> +		(!strncmp(sym, "__do_sys", 8) && !strcmp(sym + 8, name + 3));
>>   }
>>   
>>   #ifndef COMPILE_OFFSETS

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] tracing/x86: fix trace event registration for syscalls without arguments
  2020-04-27 13:16 ` Konstantin Khlebnikov
@ 2020-04-27 19:13   ` Steven Rostedt
  0 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2020-04-27 19:13 UTC (permalink / raw)
  To: Konstantin Khlebnikov
  Cc: Brian Gerst, linux-kernel, Thomas Gleixner, Dominik Brodowski,
	Andy Lutomirski, Ingo Molnar

On Mon, 27 Apr 2020 16:16:20 +0300
Konstantin Khlebnikov <khlebnikov@yandex-team.ru> wrote:

> Bump, bug still present in 5.7.0-rc3
> 
> root@kernel0:~# uname -r
> 5.7.0-rc3-test
> 
> root@kernel0:~# ls -d /sys/kernel/tracing/events/syscalls/sys_enter_{sync,fsync}
> ls: cannot access '/sys/kernel/tracing/events/syscalls/sys_enter_sync': No such file or directory
> /sys/kernel/tracing/events/syscalls/sys_enter_fsync
> 
> On 08/04/2020 21.13, Konstantin Khlebnikov wrote:
> > Syscalls without arguments now has no ABI subs, instead of that macro
> > SYSCALL_DEFINE0() defines __abi_sys_name as aliase to __do_sys_name.
> > 
> > As a result in find_syscall_meta() kallsyms_lookup() returns
> > "__do_sys_name" which does not match with declared trace event.
> > 
> > Also see commit 1c758a2202a6 ("tracing/x86: Update syscall trace events
> > to handle new prefixed syscall func names")

This is the first I've seen of this patch.

> > 
> > Fixes: d2b5de495ee9 ("x86/entry: Refactor SYSCALL_DEFINE0 macros")
> > Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
> > ---
> >   arch/x86/include/asm/ftrace.h |    5 +++--
> >   1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
> > index 85be2f506272..70b96cae5b42 100644
> > --- a/arch/x86/include/asm/ftrace.h
> > +++ b/arch/x86/include/asm/ftrace.h
> > @@ -61,11 +61,12 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name
> >   {
> >   	/*
> >   	 * Compare the symbol name with the system call name. Skip the
> > -	 * "__x64_sys", "__ia32_sys" or simple "sys" prefix.
> > +	 * "__x64_sys", "__ia32_sys", "__do_sys" or simple "sys" prefix.
> >   	 */
> >   	return !strcmp(sym + 3, name + 3) ||
> >   		(!strncmp(sym, "__x64_", 6) && !strcmp(sym + 9, name + 3)) ||
> > -		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3));
> > +		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3)) ||
> > +		(!strncmp(sym, "__do_sys", 8) && !strcmp(sym + 8, name + 3));
> >   }

Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

-- Steve

> >   
> >   #ifndef COMPILE_OFFSETS
> >   


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [tip: x86/urgent] ftrace/x86: Fix trace event registration for syscalls without arguments
  2020-04-08 18:13 [PATCH] tracing/x86: fix trace event registration for syscalls without arguments Konstantin Khlebnikov
  2020-04-27 13:16 ` Konstantin Khlebnikov
  2020-04-27 14:44 ` Thomas Gleixner
@ 2020-05-01 18:22 ` tip-bot2 for Konstantin Khlebnikov
  2 siblings, 0 replies; 6+ messages in thread
From: tip-bot2 for Konstantin Khlebnikov @ 2020-05-01 18:22 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: Konstantin Khlebnikov, Thomas Gleixner, Steven Rostedt (VMware),
	x86, LKML

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     fdc63ff0e49c588884992b4b2656345a5e878b32
Gitweb:        https://git.kernel.org/tip/fdc63ff0e49c588884992b4b2656345a5e878b32
Author:        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
AuthorDate:    Wed, 08 Apr 2020 21:13:10 +03:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 01 May 2020 19:15:40 +02:00

ftrace/x86: Fix trace event registration for syscalls without arguments

The refactoring of SYSCALL_DEFINE0() macros removed the ABI stubs and
simply defines __abi_sys_$NAME as alias of __do_sys_$NAME.

As a result kallsyms_lookup() returns "__do_sys_$NAME" which does not match
with the declared trace event name.

See also commit 1c758a2202a6 ("tracing/x86: Update syscall trace events to
handle new prefixed syscall func names").

Add __do_sys_ to the valid prefixes which are checked in
arch_syscall_match_sym_name().

Fixes: d2b5de495ee9 ("x86/entry: Refactor SYSCALL_DEFINE0 macros")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/158636958997.7900.16485049455470033557.stgit@buzz

---
 arch/x86/include/asm/ftrace.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 85be2f5..70b96ca 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -61,11 +61,12 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name
 {
 	/*
 	 * Compare the symbol name with the system call name. Skip the
-	 * "__x64_sys", "__ia32_sys" or simple "sys" prefix.
+	 * "__x64_sys", "__ia32_sys", "__do_sys" or simple "sys" prefix.
 	 */
 	return !strcmp(sym + 3, name + 3) ||
 		(!strncmp(sym, "__x64_", 6) && !strcmp(sym + 9, name + 3)) ||
-		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3));
+		(!strncmp(sym, "__ia32_", 7) && !strcmp(sym + 10, name + 3)) ||
+		(!strncmp(sym, "__do_sys", 8) && !strcmp(sym + 8, name + 3));
 }
 
 #ifndef COMPILE_OFFSETS

^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2020-05-01 18:23 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-04-08 18:13 [PATCH] tracing/x86: fix trace event registration for syscalls without arguments Konstantin Khlebnikov
2020-04-27 13:16 ` Konstantin Khlebnikov
2020-04-27 19:13   ` Steven Rostedt
2020-04-27 14:44 ` Thomas Gleixner
2020-04-27 14:55   ` Konstantin Khlebnikov
2020-05-01 18:22 ` [tip: x86/urgent] ftrace/x86: Fix " tip-bot2 for Konstantin Khlebnikov

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