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From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Eva Kurchatova <eva.kurchatova@virtuozzo.com>
Subject: [GIT PULL] tracing: Fixes for 7.1
Date: Thu, 4 Jun 2026 08:47:55 -0400	[thread overview]
Message-ID: <20260604084755.4d94063e@fedora> (raw)


Linus,

tracing fixes for 7.1:

- Fix CFI violation in probestub function

  The probestub is a function to allow tprobes to hook to a tracepoint to
  gain access to its parameters. The function itself is only referenced by
  the tracepoint structure which lives in the __tracepoint section.
  objtool explicitly ignores that section and when processing functions in
  the kernel, if it detects one that has no references it will seal it to
  have its ENDBR stripped on boot up. This means the probstub function
  will have its ENDBR stripped and if a tprobe is attached to it with IBT
  enabled, it will go *boom*.


Please pull the latest trace-v7.1-rc6 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace-v7.1-rc6

Tag SHA1: f9504915379aa495293ca8adc857a1ee27407952
Head SHA1: 0652a3daa78723f955b1ebeb621665ce72bec53e


Eva Kurchatova (1):
      tracing: Fix CFI violation in probestub being called by tprobes

----
 include/linux/tracepoint.h | 8 ++++++++
 1 file changed, 8 insertions(+)
---------------------------
commit 0652a3daa78723f955b1ebeb621665ce72bec53e
Author: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
Date:   Wed Jun 3 18:31:42 2026 +0300

    tracing: Fix CFI violation in probestub being called by tprobes
    
    The probestub is a function to allow tprobes to hook to a tracepoint to
    gain access to its parameters. The function itself is only referenced by
    the tracepoint structure which lives in the __tracepoint section. objtool
    explicitly ignores that section and when processing functions in the
    kernel, if it detects one that has no references it will seal it to have
    its ENDBR stripped on boot up.
    
    This means when a tprobe is attached to the sched_wakeup tracepoint, when it
    is triggered it will call __probestub_sched_wakeup and due to the missing
    ENDBR on a CFI-enabled machine it will take a #CP exception.
    
    Fix this by adding CFI_NOSEAL annotation to probestub declaration.
    
    Cc: stable@vger.kernel.org
    Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
    Link: https://patch.msgid.link/20260603153147.573589-1-eva.kurchatova@virtuozzo.com
    Fixes: d5173f753750 ("objtool: Exclude __tracepoints data from ENDBR checks")
    Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
    [ Updated change log ]
    Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 763eea4d80d8..2d2b9f8cdda4 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -20,6 +20,7 @@
 #include <linux/rcupdate_trace.h>
 #include <linux/tracepoint-defs.h>
 #include <linux/static_call.h>
+#include <linux/cfi.h>
 
 struct module;
 struct tracepoint;
@@ -389,6 +390,13 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 	void __probestub_##_name(void *__data, proto)			\
 	{								\
 	}								\
+	/*								\
+	 * Annotate the probestub 'CFI_NOSEAL' to stop objtool from	\
+	 * requesting the kernel remove the ENDBR, because the only	\
+	 * references to the function are in the __tracepoint section,	\
+	 * that objtool doesn't scan.					\
+	 */								\
+	CFI_NOSEAL(__probestub_##_name);				\
 	DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);	\
 	DEFINE_RUST_DO_TRACE(_name, TP_PROTO(proto), TP_ARGS(args))
 

             reply	other threads:[~2026-06-04 12:47 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-04 12:47 Steven Rostedt [this message]
2026-06-04 22:12 ` [GIT PULL] tracing: Fixes for 7.1 pr-tracker-bot
2026-06-05 15:58 ` Nathan Chancellor
2026-06-06 21:58   ` Nathan Chancellor
  -- strict thread matches above, loose matches on Subject: below --
2026-05-21 22:08 Steven Rostedt
2026-05-22 14:26 ` pr-tracker-bot
2026-05-17 13:17 Steven Rostedt
2026-05-17 19:28 ` pr-tracker-bot

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