This is a note to let you know that I've just added the patch titled
nvme/host: Fix RCU list traversal to use SRCU primitive
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nvme-host-fix-rcu-list-traversal-to-use-srcu-primiti.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8fbb007ac49668f83e523f0c7ed3e15096a3b1ce
Author: Breno Leitao <leitao@xxxxxxxxxx>
Date: Mon Nov 4 04:24:40 2024 -0800
nvme/host: Fix RCU list traversal to use SRCU primitive
[ Upstream commit 6d1c69945ce63a9fba22a4abf646cf960d878782 ]
The code currently uses list_for_each_entry_rcu() while holding an SRCU
lock, triggering false positive warnings with CONFIG_PROVE_RCU=y
enabled:
drivers/nvme/host/core.c:3770 RCU-list traversed in non-reader section!!
While the list is properly protected by SRCU lock, the code uses the wrong
list traversal primitive. Replace list_for_each_entry_rcu() with
list_for_each_entry_srcu() to correctly indicate SRCU-based protection
and eliminate the false warning.
Fixes: be647e2c76b2 ("nvme: use srcu for iterating namespace list")
Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index b3c5460c6d768..965ca7d7a3de2 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3544,7 +3544,8 @@ struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid)
int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu);
- list_for_each_entry_rcu(ns, &ctrl->namespaces, list) {
+ list_for_each_entry_srcu(ns, &ctrl->namespaces, list,
+ srcu_read_lock_held(&ctrl->srcu)) {
if (ns->head->ns_id == nsid) {
if (!nvme_get_ns(ns))
continue;
@@ -4555,7 +4556,8 @@ void nvme_mark_namespaces_dead(struct nvme_ctrl *ctrl)
int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu);
- list_for_each_entry_rcu(ns, &ctrl->namespaces, list)
+ list_for_each_entry_srcu(ns, &ctrl->namespaces, list,
+ srcu_read_lock_held(&ctrl->srcu))
blk_mark_disk_dead(ns->disk);
srcu_read_unlock(&ctrl->srcu, srcu_idx);
}
@@ -4567,7 +4569,8 @@ void nvme_unfreeze(struct nvme_ctrl *ctrl)
int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu);
- list_for_each_entry_rcu(ns, &ctrl->namespaces, list)
+ list_for_each_entry_srcu(ns, &ctrl->namespaces, list,
+ srcu_read_lock_held(&ctrl->srcu))
blk_mq_unfreeze_queue(ns->queue);
srcu_read_unlock(&ctrl->srcu, srcu_idx);
clear_bit(NVME_CTRL_FROZEN, &ctrl->flags);
@@ -4580,7 +4583,8 @@ int nvme_wait_freeze_timeout(struct nvme_ctrl *ctrl, long timeout)
int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu);
- list_for_each_entry_rcu(ns, &ctrl->namespaces, list) {
+ list_for_each_entry_srcu(ns, &ctrl->namespaces, list,
+ srcu_read_lock_held(&ctrl->srcu)) {
timeout = blk_mq_freeze_queue_wait_timeout(ns->queue, timeout);
if (timeout <= 0)
break;
@@ -4596,7 +4600,8 @@ void nvme_wait_freeze(struct nvme_ctrl *ctrl)
int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu);
- list_for_each_entry_rcu(ns, &ctrl->namespaces, list)
+ list_for_each_entry_srcu(ns, &ctrl->namespaces, list,
+ srcu_read_lock_held(&ctrl->srcu))
blk_mq_freeze_queue_wait(ns->queue);
srcu_read_unlock(&ctrl->srcu, srcu_idx);
}
@@ -4609,7 +4614,8 @@ void nvme_start_freeze(struct nvme_ctrl *ctrl)
set_bit(NVME_CTRL_FROZEN, &ctrl->flags);
srcu_idx = srcu_read_lock(&ctrl->srcu);
- list_for_each_entry_rcu(ns, &ctrl->namespaces, list)
+ list_for_each_entry_srcu(ns, &ctrl->namespaces, list,
+ srcu_read_lock_held(&ctrl->srcu))
blk_freeze_queue_start(ns->queue);
srcu_read_unlock(&ctrl->srcu, srcu_idx);
}
@@ -4657,7 +4663,8 @@ void nvme_sync_io_queues(struct nvme_ctrl *ctrl)
int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu);
- list_for_each_entry_rcu(ns, &ctrl->namespaces, list)
+ list_for_each_entry_srcu(ns, &ctrl->namespaces, list,
+ srcu_read_lock_held(&ctrl->srcu))
blk_sync_queue(ns->queue);
srcu_read_unlock(&ctrl->srcu, srcu_idx);
}
