Messages in this thread | | | Subject | Re: [PATCH -next 1/3] md/raid10: fix improper BUG_ON() in raise_barrier() | From | Yu Kuai <> | Date | Tue, 30 Aug 2022 09:01:49 +0800 |
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Hi, John
在 2022/08/30 3:53, John Stoffel 写道: >>>>>> "Yu" == Yu Kuai <yukuai1@huaweicloud.com> writes: > > Yu> From: Yu Kuai <yukuai3@huawei.com> > Yu> 'conf->barrier' is protected by 'conf->resync_lock', reading > Yu> 'conf->barrier' without holding the lock is wrong. > > Yu> Signed-off-by: Yu Kuai <yukuai3@huawei.com> > Yu> --- > Yu> drivers/md/raid10.c | 2 +- > Yu> 1 file changed, 1 insertion(+), 1 deletion(-) > > Yu> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c > Yu> index 9117fcdee1be..b70c207f7932 100644 > Yu> --- a/drivers/md/raid10.c > Yu> +++ b/drivers/md/raid10.c > Yu> @@ -930,8 +930,8 @@ static void flush_pending_writes(struct r10conf *conf) > > Yu> static void raise_barrier(struct r10conf *conf, int force) > Yu> { > Yu> - BUG_ON(force && !conf->barrier); > Yu> spin_lock_irq(&conf->resync_lock); > Yu> + BUG_ON(force && !conf->barrier); > > I don't like this BUG_ON() at all, why are you crashing the system > here instead of just doing a simple WARN_ONCE() instead? Is there > anything the user can do to get into this situation on their own, or > does it really signify a logic error in the code? If so, why are you > killing the system?
I'm not sure why to use the BUG_ON() here. I just noticed that 'conf->barrier' is read without holding 'resync_lock', and BUG_ON() can be triggered false positive.
Thanks, Kuai > > > > Yu> /* Wait until no block IO is waiting (unless 'force') */ > Yu> wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting, > Yu> -- > Yu> 2.31.1 > > > . >
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