From: Yu Kuai <[email protected]>
'conf->barrier' is protected by 'conf->resync_lock', reading
'conf->barrier' without holding the lock is wrong.
Signed-off-by: Yu Kuai <[email protected]>
---
drivers/md/raid10.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 9117fcdee1be..b70c207f7932 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -930,8 +930,8 @@ static void flush_pending_writes(struct r10conf *conf)
static void raise_barrier(struct r10conf *conf, int force)
{
- BUG_ON(force && !conf->barrier);
spin_lock_irq(&conf->resync_lock);
+ BUG_ON(force && !conf->barrier);
/* Wait until no block IO is waiting (unless 'force') */
wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
--
2.31.1
>>>>> "Yu" == Yu Kuai <[email protected]> writes:
Yu> From: Yu Kuai <[email protected]>
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 <[email protected]>
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?
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
Hi, John
?? 2022/08/30 3:53, John Stoffel д??:
>>>>>> "Yu" == Yu Kuai <[email protected]> writes:
>
> Yu> From: Yu Kuai <[email protected]>
> 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 <[email protected]>
> 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
>
>
> .
>
Dear John,
Am 29.08.22 um 21:53 schrieb John Stoffel:
>>>>>> "Yu" == Yu Kuai <[email protected]> writes:
>
> Yu> From: Yu Kuai <[email protected]>
The quoting style is really confusing, as it does not seem to be the
standard, and a lot of MUAs won’t mark up the citation.
[…]
> 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 <[email protected]>
> 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?
As you can see, the BUG_ON() was there before, so it’s unrelated to this
patch and Yun is not killing anything.
[…]
> 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
Kind regards,
Paul