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-rw-r--r--arch/csky/kernel/probes/ftrace.c2
-rw-r--r--arch/parisc/kernel/ftrace.c2
-rw-r--r--arch/powerpc/kernel/kprobes-ftrace.c2
-rw-r--r--arch/riscv/kernel/probes/ftrace.c2
-rw-r--r--arch/x86/kernel/kprobes/ftrace.c2
-rw-r--r--include/linux/trace_recursion.h11
-rw-r--r--kernel/livepatch/patch.c12
-rw-r--r--kernel/trace/ftrace.c15
-rw-r--r--kernel/trace/trace_functions.c5
9 files changed, 21 insertions, 32 deletions
diff --git a/arch/csky/kernel/probes/ftrace.c b/arch/csky/kernel/probes/ftrace.c
index b388228abbf2..834cffcfbce3 100644
--- a/arch/csky/kernel/probes/ftrace.c
+++ b/arch/csky/kernel/probes/ftrace.c
@@ -17,7 +17,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
return;
regs = ftrace_get_regs(fregs);
- preempt_disable_notrace();
p = get_kprobe((kprobe_opcode_t *)ip);
if (!p) {
p = get_kprobe((kprobe_opcode_t *)(ip - MCOUNT_INSN_SIZE));
@@ -57,7 +56,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
__this_cpu_write(current_kprobe, NULL);
}
out:
- preempt_enable_notrace();
ftrace_test_recursion_unlock(bit);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c
index 01581f715737..b14011d3c2f1 100644
--- a/arch/parisc/kernel/ftrace.c
+++ b/arch/parisc/kernel/ftrace.c
@@ -211,7 +211,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
return;
regs = ftrace_get_regs(fregs);
- preempt_disable_notrace();
p = get_kprobe((kprobe_opcode_t *)ip);
if (unlikely(!p) || kprobe_disabled(p))
goto out;
@@ -240,7 +239,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
}
__this_cpu_write(current_kprobe, NULL);
out:
- preempt_enable_notrace();
ftrace_test_recursion_unlock(bit);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c
index 7154d58338cc..072ebe7f290b 100644
--- a/arch/powerpc/kernel/kprobes-ftrace.c
+++ b/arch/powerpc/kernel/kprobes-ftrace.c
@@ -26,7 +26,6 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
return;
regs = ftrace_get_regs(fregs);
- preempt_disable_notrace();
p = get_kprobe((kprobe_opcode_t *)nip);
if (unlikely(!p) || kprobe_disabled(p))
goto out;
@@ -61,7 +60,6 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
__this_cpu_write(current_kprobe, NULL);
}
out:
- preempt_enable_notrace();
ftrace_test_recursion_unlock(bit);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
diff --git a/arch/riscv/kernel/probes/ftrace.c b/arch/riscv/kernel/probes/ftrace.c
index aab85a82f419..7142ec42e889 100644
--- a/arch/riscv/kernel/probes/ftrace.c
+++ b/arch/riscv/kernel/probes/ftrace.c
@@ -15,7 +15,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
if (bit < 0)
return;
- preempt_disable_notrace();
p = get_kprobe((kprobe_opcode_t *)ip);
if (unlikely(!p) || kprobe_disabled(p))
goto out;
@@ -52,7 +51,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
__this_cpu_write(current_kprobe, NULL);
}
out:
- preempt_enable_notrace();
ftrace_test_recursion_unlock(bit);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c
index 596de2f6d3a5..dd2ec14adb77 100644
--- a/arch/x86/kernel/kprobes/ftrace.c
+++ b/arch/x86/kernel/kprobes/ftrace.c
@@ -25,7 +25,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
if (bit < 0)
return;
- preempt_disable_notrace();
p = get_kprobe((kprobe_opcode_t *)ip);
if (unlikely(!p) || kprobe_disabled(p))
goto out;
@@ -59,7 +58,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
__this_cpu_write(current_kprobe, NULL);
}
out:
- preempt_enable_notrace();
ftrace_test_recursion_unlock(bit);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h
index 24f284eb55a7..a13f23b04d73 100644
--- a/include/linux/trace_recursion.h
+++ b/include/linux/trace_recursion.h
@@ -155,6 +155,9 @@ extern void ftrace_record_recursion(unsigned long ip, unsigned long parent_ip);
# define do_ftrace_record_recursion(ip, pip) do { } while (0)
#endif
+/*
+ * Preemption is promised to be disabled when return bit >= 0.
+ */
static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsigned long pip,
int start, int max)
{
@@ -189,14 +192,20 @@ static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsign
current->trace_recursion = val;
barrier();
+ preempt_disable_notrace();
+
return bit + 1;
}
+/*
+ * Preemption will be enabled (if it was previously enabled).
+ */
static __always_inline void trace_clear_recursion(int bit)
{
if (!bit)
return;
+ preempt_enable_notrace();
barrier();
bit--;
trace_recursion_clear(bit);
@@ -209,7 +218,7 @@ static __always_inline void trace_clear_recursion(int bit)
* tracing recursed in the same context (normal vs interrupt),
*
* Returns: -1 if a recursion happened.
- * >= 0 if no recursion
+ * >= 0 if no recursion.
*/
static __always_inline int ftrace_test_recursion_trylock(unsigned long ip,
unsigned long parent_ip)
diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
index e8029aea67f1..fe316c021d73 100644
--- a/kernel/livepatch/patch.c
+++ b/kernel/livepatch/patch.c
@@ -49,14 +49,15 @@ static void notrace klp_ftrace_handler(unsigned long ip,
ops = container_of(fops, struct klp_ops, fops);
+ /*
+ * The ftrace_test_recursion_trylock() will disable preemption,
+ * which is required for the variant of synchronize_rcu() that is
+ * used to allow patching functions where RCU is not watching.
+ * See klp_synchronize_transition() for more details.
+ */
bit = ftrace_test_recursion_trylock(ip, parent_ip);
if (WARN_ON_ONCE(bit < 0))
return;
- /*
- * A variant of synchronize_rcu() is used to allow patching functions
- * where RCU is not watching, see klp_synchronize_transition().
- */
- preempt_disable_notrace();
func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
stack_node);
@@ -120,7 +121,6 @@ static void notrace klp_ftrace_handler(unsigned long ip,
klp_arch_set_pc(fregs, (unsigned long)func->new_func);
unlock:
- preempt_enable_notrace();
ftrace_test_recursion_unlock(bit);
}
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 2057ad363772..b4ed1a301232 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -7198,16 +7198,15 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op;
int bit;
+ /*
+ * The ftrace_test_and_set_recursion() will disable preemption,
+ * which is required since some of the ops may be dynamically
+ * allocated, they must be freed after a synchronize_rcu().
+ */
bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START, TRACE_LIST_MAX);
if (bit < 0)
return;
- /*
- * Some of the ops may be dynamically allocated,
- * they must be freed after a synchronize_rcu().
- */
- preempt_disable_notrace();
-
do_for_each_ftrace_op(op, ftrace_ops_list) {
/* Stub functions don't need to be called nor tested */
if (op->flags & FTRACE_OPS_FL_STUB)
@@ -7231,7 +7230,6 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
}
} while_for_each_ftrace_op(op);
out:
- preempt_enable_notrace();
trace_clear_recursion(bit);
}
@@ -7279,12 +7277,9 @@ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
if (bit < 0)
return;
- preempt_disable_notrace();
-
if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
op->func(ip, parent_ip, op, fregs);
- preempt_enable_notrace();
trace_clear_recursion(bit);
}
NOKPROBE_SYMBOL(ftrace_ops_assist_func);
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 1f0e63f5d1f9..9f1bfbe105e8 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -186,7 +186,6 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
return;
trace_ctx = tracing_gen_ctx();
- preempt_disable_notrace();
cpu = smp_processor_id();
data = per_cpu_ptr(tr->array_buffer.data, cpu);
@@ -194,7 +193,6 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
trace_function(tr, ip, parent_ip, trace_ctx);
ftrace_test_recursion_unlock(bit);
- preempt_enable_notrace();
}
#ifdef CONFIG_UNWINDER_ORC
@@ -298,8 +296,6 @@ function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
if (bit < 0)
return;
- preempt_disable_notrace();
-
cpu = smp_processor_id();
data = per_cpu_ptr(tr->array_buffer.data, cpu);
if (atomic_read(&data->disabled))
@@ -324,7 +320,6 @@ function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
out:
ftrace_test_recursion_unlock(bit);
- preempt_enable_notrace();
}
static void
generated by cgit (git 2.34.1) at 2024-05-24 13:27:28 +0000