Commit 68af44a7 authored by Breno Leitao's avatar Breno Leitao Committed by Mimi Zohar
Browse files

ima: kexec: silence RCU list traversal warning 



The ima_measurements list is append-only and doesn't require
rcu_read_lock() protection. However, lockdep issues a warning when
traversing RCU lists without the read lock:

  security/integrity/ima/ima_kexec.c:40 RCU-list traversed in non-reader section!!

Fix this by using the variant of list_for_each_entry_rcu() with the last
argument set to true. This tells the RCU subsystem that traversing this
append-only list without the read lock is intentional and safe.

This change silences the lockdep warning while maintaining the correct
semantics for the append-only list traversal.

Signed-off-by: default avatarBreno Leitao <leitao@debian.org>
Signed-off-by: default avatarMimi Zohar <zohar@linux.ibm.com>
parent 254ef954

security/integrity/ima/ima_kexec.c

+2 −1
Original line number Diff line number Diff line
@@ -37,7 +37,8 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, 


	memset(&khdr, 0, sizeof(khdr));

	khdr.version = 1;

	list_for_each_entry_rcu(qe, &ima_measurements, later) {

	/* This is an append-only list, no need to hold the RCU read lock */

	list_for_each_entry_rcu(qe, &ima_measurements, later, true) {

		if (file.count < file.size) {

			khdr.count++;

			ima_measurements_show(&file, qe);