[PATCH 0/2] tracing: s390: Fix fprobes on s390

[PATCH 0/2] tracing: s390: Fix fprobes on s390

[Masami Hiramatsu (Google)]

Hi,

Here are fprobe and kprobe-multi fix patches for s390 which maybe broken
when we introduced fprobes on fgraph series.

Thank you,

---

Masami Hiramatsu (Google) (2):
      s390: fgraph: Fix to remove ftrace_test_recursion_trylock()
      s390: tracing: Define ftrace_get_symaddr() for s390


 arch/s390/include/asm/ftrace.h |    1 +
 arch/s390/kernel/ftrace.c      |    5 -----
 2 files changed, 1 insertion(+), 5 deletions(-)

--
Masami Hiramatsu (Google) <mhiramat@kernel.org>

[PATCH 1/2] s390: fgraph: Fix to remove ftrace_test_recursion_trylock()

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Fix to remove ftrace_test_recursion_trylock() from ftrace_graph_func()
because commit d576aec24df9 ("fgraph: Get ftrace recursion lock in
function_graph_enter") has been moved it to function_graph_enter_regs()
already.

Reported-by: Jiri Olsa <olsajiri@gmail.com>
Closes: https://lore.kernel.org/all/Z5O0shrdgeExZ2kF@krava/
Fixes: d576aec24df9 ("fgraph: Get ftrace recursion lock in function_graph_enter")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
---
 arch/s390/kernel/ftrace.c |    5 -----
 1 file changed, 5 deletions(-)

diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index c0b2c97efefb..63ba6306632e 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -266,18 +266,13 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
 		       struct ftrace_ops *op, struct ftrace_regs *fregs)
 {
 	unsigned long *parent = &arch_ftrace_regs(fregs)->regs.gprs[14];
-	int bit;
 
 	if (unlikely(ftrace_graph_is_dead()))
 		return;
 	if (unlikely(atomic_read(&current->tracing_graph_pause)))
 		return;
-	bit = ftrace_test_recursion_trylock(ip, *parent);
-	if (bit < 0)
-		return;
 	if (!function_graph_enter_regs(*parent, ip, 0, parent, fregs))
 		*parent = (unsigned long)&return_to_handler;
-	ftrace_test_recursion_unlock(bit);
 }
 
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */

[PATCH 2/2] s390: tracing: Define ftrace_get_symaddr() for s390

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Add ftrace_get_symaddr() for s390, which returns the symbol address
from ftrace's 'ip' parameter.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 arch/s390/include/asm/ftrace.h |    1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index a3b73a4f626e..185331e91f83 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -51,6 +51,7 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {
 	return addr;
 }
+#define ftrace_get_symaddr(fentry_ip) ((unsigned long)(fentry_ip))
 
 #include <linux/ftrace_regs.h>
 

Re: [PATCH 1/2] s390: fgraph: Fix to remove ftrace_test_recursion_trylock()

[Ihor Solodrai]

January 28, 2025 at 7:29 AM, "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:



> 
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Fix to remove ftrace_test_recursion_trylock() from ftrace_graph_func()
> 
> because commit d576aec24df9 ("fgraph: Get ftrace recursion lock in
> 
> function_graph_enter") has been moved it to function_graph_enter_regs()
> 
> already.
> 
> Reported-by: Jiri Olsa <olsajiri@gmail.com>
> 
> Closes: https://lore.kernel.org/all/Z5O0shrdgeExZ2kF@krava/
> 
> Fixes: d576aec24df9 ("fgraph: Get ftrace recursion lock in function_graph_enter")
> 
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Tested-by: Jiri Olsa <jolsa@kernel.org>
> 
> [...]

Hi Masami,

Can confirm this patch fixes missed/kprobe_recursion BPF selftests on s390x:
https://github.com/kernel-patches/vmtest/actions/runs/13021621468/job/36324248903

Tested-by: Ihor Solodrai <ihor.solodrai@linux.dev>

Thanks!

Re: [PATCH 0/2] tracing: s390: Fix fprobes on s390

[Heiko Carstens]

On Wed, Jan 29, 2025 at 12:29:25AM +0900, Masami Hiramatsu (Google) wrote:
> Hi,
> 
> Here are fprobe and kprobe-multi fix patches for s390 which maybe broken
> when we introduced fprobes on fgraph series.
> 
> Thank you,
> 
> ---
> 
> Masami Hiramatsu (Google) (2):
>       s390: fgraph: Fix to remove ftrace_test_recursion_trylock()
>       s390: tracing: Define ftrace_get_symaddr() for s390
> 
> 
>  arch/s390/include/asm/ftrace.h |    1 +
>  arch/s390/kernel/ftrace.c      |    5 -----
>  2 files changed, 1 insertion(+), 5 deletions(-)

For both patches:
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>