From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 11 Feb 2015 04:31:13 +0000 (+1030)
Subject: module: Annotate nested sleep in resolve_symbol()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d64810f56147b53e92228c31442e925576314aa2;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

module: Annotate nested sleep in resolve_symbol()

Because wait_event() loops are safe vs spurious wakeups we can allow the
occasional sleep -- which ends up being very similar.

Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---

diff --git a/kernel/module.c b/kernel/module.c
index 2461370813b3..d7a92682fba3 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1225,6 +1225,12 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 	const unsigned long *crc;
 	int err;
 
+	/*
+	 * The module_mutex should not be a heavily contended lock;
+	 * if we get the occasional sleep here, we'll go an extra iteration
+	 * in the wait_event_interruptible(), which is harmless.
+	 */
+	sched_annotate_sleep();
 	mutex_lock(&module_mutex);
 	sym = find_symbol(name, &owner, &crc,
 			  !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);