Revert "kernel/panic.c: Move the location of bust_spinlocks to prevent hanging."

Upstream Status: RHEL-only

JIRA: https://issues.redhat.com/browse/RHEL-39473

This reverts commit 065095b.

Now that the upstream printk code has landed in c9s, remove the
extraneous "bust_spinlock(1)" that remained after merge to prevent the
abrupt "cut off" of call traces during panic.

Revert
commit 065095b
Author: Derek Barbosa <debarbos@redhat.com>
Date:   Wed Dec 6 09:09:56 2023 -0500

    kernel/panic.c: Move the location of bust_spinlocks to prevent hanging.

    JIRA: https://issues.redhat.com/browse/RHEL-15897
    Upstream Status: RHEL-Only

    Moving bust_spinlocks() closer to pr_emerge in the panic() function
    (specifically prior to flushing the consoles) addresses the
    issue of the kernel hanging while printing out a call trace during a
    panic.

    Signed-off-by: Derek Barbosa <debarbos@redhat.com>

Signed-off-by: Derek Barbosa <debarbos@redhat.com>

Author: Derek Barbosa

kernel/panic.c

@@ -331,10 +331,6 @@ void panic(const char *fmt, ...)
 		buf[len - 1] = '\0';
 
 	pr_emerg("Kernel panic - not syncing: %s\n", buf);
-
-	/* Bust spinlocks before flushing console on panic to prevent hangs */
-	bust_spinlocks(1);
-
 #ifdef CONFIG_DEBUG_BUGVERBOSE
 	/*
 	 * Avoid nested stack-dumping if a panic occurs during oops processing
@@ -363,14 +359,14 @@ void panic(const char *fmt, ...)
 
 	panic_other_cpus_shutdown(_crash_kexec_post_notifiers);
 
+	printk_legacy_allow_panic_sync();
+
 	/*
 	 * Run any panic handlers, including those that might need to
 	 * add information to the kmsg dump output.
 	 */
 	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
 
-	printk_legacy_allow_panic_sync();
-
 	panic_print_sys_info(false);
 
 	kmsg_dump(KMSG_DUMP_PANIC);