5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Wang Jinchao wangjinchao600@gmail.com
[ Upstream commit d67ed2ccd2d1dcfda9292c0ea8697a9d0f2f0d98 ]
In the raid1_reshape function, newpool is allocated on the stack and assigned to conf->r1bio_pool. This results in conf->r1bio_pool.wait.head pointing to a stack address. Accessing this address later can lead to a kernel panic.
Example access path:
raid1_reshape() { // newpool is on the stack mempool_t newpool, oldpool; // initialize newpool.wait.head to stack address mempool_init(&newpool, ...); conf->r1bio_pool = newpool; }
raid1_read_request() or raid1_write_request() { alloc_r1bio() { mempool_alloc() { // if pool->alloc fails remove_element() { --pool->curr_nr; } } } }
mempool_free() { if (pool->curr_nr < pool->min_nr) { // pool->wait.head is a stack address // wake_up() will try to access this invalid address // which leads to a kernel panic return; wake_up(&pool->wait); } }
Fix: reinit conf->r1bio_pool.wait after assigning newpool.
Fixes: afeee514ce7f ("md: convert to bioset_init()/mempool_init()") Signed-off-by: Wang Jinchao wangjinchao600@gmail.com Reviewed-by: Yu Kuai yukuai3@huawei.com Link: https://lore.kernel.org/linux-raid/20250612112901.3023950-1-wangjinchao600@g... Signed-off-by: Yu Kuai yukuai3@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/raid1.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 395a279e2c885..dccf62e5b4978 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -3307,6 +3307,7 @@ static int raid1_reshape(struct mddev *mddev) /* ok, everything is stopped */ oldpool = conf->r1bio_pool; conf->r1bio_pool = newpool; + init_waitqueue_head(&conf->r1bio_pool.wait);
for (d = d2 = 0; d < conf->raid_disks; d++) { struct md_rdev *rdev = conf->mirrors[d].rdev;