On Thu, Oct 03, 2024 at 07:21:25AM -0600, Jens Axboe wrote:
> On 10/3/24 6:03 AM, Dan Carpenter wrote:
> > 3117 ioc_now(iocg->ioc, &now);
> > 3118 weight_updated(iocg, &now);
> > 3119 spin_unlock(&iocg->ioc->lock);
> > 3120 }
> > 3121 }
> > 3122 spin_unlock_irq(&blkcg->lock);
> > 3123
> > 3124 return nbytes;
> > 3125 }
> > 3126
> > 3127 blkg_conf_init(&ctx, buf);
> > 3128
> > 3129 ret = blkg_conf_prep(blkcg, &blkcg_policy_iocost, &ctx);
> > 3130 if (ret)
> > 3131 goto err;
> > 3132
> > 3133 iocg = blkg_to_iocg(ctx.blkg);
> > 3134
> > 3135 if (!strncmp(ctx.body, "default", 7)) {
> > 3136 v = 0;
> > 3137 } else {
> > 3138 if (!sscanf(ctx.body, "%u", &v))
> > 3139 goto einval;
> > 3140 if (v < CGROUP_WEIGHT_MIN || v > CGROUP_WEIGHT_MAX)
> > 3141 goto einval;
> > 3142 }
> > 3143
> > 3144 spin_lock(&iocg->ioc->lock);
> >
> > But why is this not spin_lock_irq()? I haven't analyzed this so maybe it's
> > fine.
>
> That's a bug.
>
I could obviously write this patch but I feel stupid writing the commit message.
My level of understanding is Monkey See Monkey do. Could you take care of this?
So somewhere we're taking a lock in the IRQ handler and this can lead to a
deadlock? I thought this would have been caught by lockdep?
regards,
dan carpenter
