mainline inclusion from mainline-v6.9-rc5 commit 01bc4fda9ea0a6b52f12326486f07a4910666cf6 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9UABH CVE: CVE-2024-36908

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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In iocg_pay_debt(), warn is triggered if 'active_list' is empty, which is intended to confirm iocg is active when it has debt. However, warn can be triggered during a blkcg or disk removal, if iocg_waitq_timer_fn() is run at that time:

WARNING: CPU: 0 PID: 2344971 at block/blk-iocost.c:1402 iocg_pay_debt+0x14c/0x190 Call trace: iocg_pay_debt+0x14c/0x190 iocg_kick_waitq+0x438/0x4c0 iocg_waitq_timer_fn+0xd8/0x130 __run_hrtimer+0x144/0x45c __hrtimer_run_queues+0x16c/0x244 hrtimer_interrupt+0x2cc/0x7b0

The warn in this situation is meaningless. Since this iocg is being removed, the state of the 'active_list' is irrelevant, and 'waitq_timer' is canceled after removing 'active_list' in ioc_pd_free(), which ensures iocg is freed after iocg_waitq_timer_fn() returns.

Therefore, add the check if iocg was already offlined to avoid warn when removing a blkcg or disk.

Signed-off-by: Li Nan linan122@huawei.com Reviewed-by: Yu Kuai yukuai3@huawei.com Acked-by: Tejun Heo tj@kernel.org Link: https://lore.kernel.org/r/20240419093257.3004211-1-linan666@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Li Nan linan122@huawei.com --- block/blk-iocost.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 6a3e8a21c0fc..3ac79f0c098f 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -1439,8 +1439,11 @@ static void iocg_pay_debt(struct ioc_gq *iocg, u64 abs_vpay, lockdep_assert_held(&iocg->ioc->lock); lockdep_assert_held(&iocg->waitq.lock);

- /* make sure that nobody messed with @iocg */ - WARN_ON_ONCE(list_empty(&iocg->active_list)); + /* + * make sure that nobody messed with @iocg. Check iocg->pd.online + * to avoid warn when removing blkcg or disk. + */ + WARN_ON_ONCE(list_empty(&iocg->active_list) && iocg->pd.online); WARN_ON_ONCE(iocg->inuse > 1);

iocg->abs_vdebt -= min(abs_vpay, iocg->abs_vdebt);