Thread (76 messages) flat view 76 messages, 12 authors, 2023-10-09
STALE1033d

Revision v2 of 7 in this series.

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[RFC PATCH v2 13/20] context_tracking: Make context_tracking_key __ro_after_init

From: Valentin Schneider <vschneid@redhat.com>
Date: 2023-07-20 16:35:50
Also in: bpf, kvm, linux-doc, linux-kselftest, linux-mm, lkml, rcu
Subsystem: context tracking, the rest · Maintainers: Frederic Weisbecker, "Paul E. McKenney", Linus Torvalds

objtool now warns about it:

  vmlinux.o: warning: objtool: enter_from_user_mode+0x4e: Non __ro_after_init static key "context_tracking_key" in .noinstr section
  vmlinux.o: warning: objtool: enter_from_user_mode+0x50: Non __ro_after_init static key "context_tracking_key" in .noinstr section
  vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x60: Non __ro_after_init static key "context_tracking_key" in .noinstr section
  vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x62: Non __ro_after_init static key "context_tracking_key" in .noinstr section
  [...]

The key can only be enabled (and not disabled) in the __init function
ct_cpu_tracker_user(), so mark it as __ro_after_init.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 kernel/context_tracking.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 6ef0b35fc28c5..cc4f3a57f848c 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -432,7 +432,7 @@ static __always_inline void ct_kernel_enter(bool user, int offset) { }
 #define CREATE_TRACE_POINTS
 #include <trace/events/context_tracking.h>
 
-DEFINE_STATIC_KEY_FALSE(context_tracking_key);
+DEFINE_STATIC_KEY_FALSE_RO(context_tracking_key);
 EXPORT_SYMBOL_GPL(context_tracking_key);
 
 static noinstr bool context_tracking_recursion_enter(void)
-- 
2.31.1
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