Merge tag 'v6.8-rc4' into x86/percpu, to resolve conflicts and refresh the branch

Conflicts:
	arch/x86/include/asm/percpu.h
	arch/x86/include/asm/text-patching.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 14 insertions, 9 deletions

diff --git a/kernel/panic.c b/kernel/panic.c
index 07239d4ad81e..2807639aab51 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -192,14 +192,15 @@ atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
  */
 void nmi_panic(struct pt_regs *regs, const char *msg)
 {
-	int old_cpu, cpu;
+	int old_cpu, this_cpu;
 
-	cpu = raw_smp_processor_id();
-	old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
+	old_cpu = PANIC_CPU_INVALID;
+	this_cpu = raw_smp_processor_id();
 
-	if (old_cpu == PANIC_CPU_INVALID)
+	/* atomic_try_cmpxchg updates old_cpu on failure */
+	if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu))
 		panic("%s", msg);
-	else if (old_cpu != cpu)
+	else if (old_cpu != this_cpu)
 		nmi_panic_self_stop(regs);
 }
 EXPORT_SYMBOL(nmi_panic);
@@ -311,15 +312,18 @@ void panic(const char *fmt, ...)
 	 * stop themself or will wait until they are stopped by the 1st CPU
 	 * with smp_send_stop().
 	 *
-	 * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which
-	 * comes here, so go ahead.
+	 * cmpxchg success means this is the 1st CPU which comes here,
+	 * so go ahead.
 	 * `old_cpu == this_cpu' means we came from nmi_panic() which sets
 	 * panic_cpu to this CPU.  In this case, this is also the 1st CPU.
 	 */
+	old_cpu = PANIC_CPU_INVALID;
 	this_cpu = raw_smp_processor_id();
-	old_cpu  = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
 
-	if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
+	/* atomic_try_cmpxchg updates old_cpu on failure */
+	if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) {
+		/* go ahead */
+	} else if (old_cpu != this_cpu)
 		panic_smp_self_stop();
 
 	console_verbose();
@@ -697,6 +701,7 @@ void warn_slowpath_fmt(const char *file, int line, unsigned taint,
 	if (!fmt) {
 		__warn(file, line, __builtin_return_address(0), taint,
 		       NULL, NULL);
+		warn_rcu_exit(rcu);
 		return;
 	}