Hi experts
If I offline one CPU on initiator side and nvmetcli clear on target side, it will cause kernel NULL pointer on initiator side, could you help check it, thanks
Steps to reproduce:
1. setup nvmet target with null-blk device:
#modprobe nvmet
#modprobe nvmet-rdma
#modprobe null_blk nr_devices=1
#nvmetcli restore rdma.json
2. connect the target on initiator side and offline one cpu:
#modprobe nvme-rdma
#nvme connect-all -t rdma -a 172.31.2.3 -s 1023
#echo 0 > /sys/devices/system/cpu/cpu1/online
3. nvmetcli clear on target side
#nvmetcli clear
Kernel log:
[ 125.039340] nvme nvme0: new ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery", addr 172.31.2.3:1023
[ 125.160587] nvme nvme0: creating 16 I/O queues.
[ 125.602244] nvme nvme0: new ctrl: NQN "testnqn", addr 172.31.2.3:1023
[ 140.930343] Broke affinity for irq 16
[ 140.950295] Broke affinity for irq 28
[ 140.969957] Broke affinity for irq 70
[ 140.986584] Broke affinity for irq 90
[ 141.003160] Broke affinity for irq 93
[ 141.019779] Broke affinity for irq 97
[ 141.036341] Broke affinity for irq 100
[ 141.053782] Broke affinity for irq 104
[ 141.072860] smpboot: CPU 1 is now offline
[ 154.768104] nvme nvme0: reconnecting in 10 seconds
[ 165.349689] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 165.387783] IP: blk_mq_reinit_tagset+0x35/0x80
Looks like blk_mq_reinit_tagset is not aware that tags can go away with
cpu hotplug...
Does this fix your issue:
--
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index e48bc2c72615..9d97bfc4d465 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -295,6 +295,9 @@ int blk_mq_reinit_tagset(struct blk_mq_tag_set *set)
for (i = 0; i < set->nr_hw_queues; i++) {
struct blk_mq_tags *tags = set->tags[i];
+ if (!tags)
+ continue;
+
for (j = 0; j < tags->nr_tags; j++) {
if (!tags->static_rqs[j])
continue;
--
--
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