[PATCH 6.12 088/265] ima: kexec: silence RCU list traversal warning

Greg Kroah-Hartman
2026-03-12T20:19:35Z

From: Breno Leitao <leitao@debian.org>

[ Upstream commit 68af44a71975688b881ea524e2526bb7c7ad0e9a ]

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: Breno Leitao <leitao@debian.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Stable-dep-of: 10d1c75ed438 ("ima: verify the previous kernel's IMA buffer lies in addressable RAM")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/integrity/ima/ima_kexec.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index 52e00332defed..9d45f4d26f731 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -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);
--
2.51.0