Re: [Bug][xfstests xfs/556] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage

[Zorro Lang <zlang@redhat.com>]

On Sun, Mar 22, 2026 at 02:20:25AM +0800, Zorro Lang wrote:
> On Fri, Mar 20, 2026 at 09:34:44AM -0700, Darrick J. Wong wrote:
> > On Fri, Mar 20, 2026 at 03:43:03AM +0800, Zorro Lang wrote:
> > > Hi,
> > > 
> > > While running fstests xfs/556 on kernel 7.0.0-rc4+ (HEAD=04a9f1766954), a
> > > lockdep warning was triggered indicating an inconsistent lock state for
> > > sb->s_type->i_lock_key.
> > > 
> > > The deadlock might occur because iomap_read_end_io (called from a hardware
> > > interrupt completion path) invokes fserror_report, which then calls igrab.
> > > igrab attempts to acquire the i_lock spinlock. However, the i_lock is frequently
> > > acquired in process context with interrupts enabled. If an interrupt occurs while
> > > a process holds the i_lock, and that interrupt handler calls fserror_report, the
> > > system deadlocks.
> > > 
> > > I hit this warning several times by running xfs/556 (mostly) or generic/648
> > > on xfs. More details refer to below console log.
> > > 
> > > Thanks,
> > > Zorro
> > 
> > Does the patch below fix the lockdep complaint for you?  It fixes it
> > here on my local machine...
> 
> I'll give it a test :)

Hi Darrick,

Your patch is good to me too, my testing tests passed with this patch :)

Thanks,
Zorro

> 
> Thanks,
> Zorro
> 
> > 
> > diff --git a/fs/iomap/bio.c b/fs/iomap/bio.c
> > index fc045f2e4c459e..cf98247e51f81e 100644
> > --- a/fs/iomap/bio.c
> > +++ b/fs/iomap/bio.c
> > @@ -8,7 +8,15 @@
> >  #include "internal.h"
> >  #include "trace.h"
> >  
> > -static void iomap_read_end_io(struct bio *bio)
> > +struct iomap_failed_bio {
> > +	struct list_head io_list;
> > +	struct bio *bio;
> > +};
> > +
> > +static DEFINE_SPINLOCK(failed_read_lock);
> > +static LIST_HEAD(failed_read_list);
> > +
> > +static void __iomap_read_end_io(struct bio *bio)
> >  {
> >  	int error = blk_status_to_errno(bio->bi_status);
> >  	struct folio_iter fi;
> > @@ -18,6 +26,61 @@ static void iomap_read_end_io(struct bio *bio)
> >  	bio_put(bio);
> >  }
> >  
> > +static void
> > +iomap_fail_reads(
> > +	struct work_struct	*work)
> > +{
> > +	struct iomap_failed_bio	*fb;
> > +	struct list_head	tmp;
> > +	unsigned long		flags;
> > +
> > +	spin_lock_irqsave(&failed_read_lock, flags);
> > +	list_replace_init(&failed_read_list, &tmp);
> > +	spin_unlock_irqrestore(&failed_read_lock, flags);
> > +
> > +	while ((fb = list_first_entry_or_null(&tmp, struct iomap_failed_bio,
> > +			io_list))) {
> > +		list_del_init(&fb->io_list);
> > +		__iomap_read_end_io(fb->bio);
> > +		kfree(fb);
> > +		cond_resched();
> > +	}
> > +}
> > +
> > +static DECLARE_WORK(failed_read_work, iomap_fail_reads);
> > +
> > +static void iomap_fail_buffered_read(struct iomap_failed_bio *fb)
> > +{
> > +	unsigned long flags;
> > +
> > +	/*
> > +	 * Bounce I/O errors to a workqueue to avoid nested i_lock acquisitions
> > +	 * in the fserror code.  The caller no longer owns the fb reference
> > +	 * after the spinlock drops.
> > +	 */
> > +	spin_lock_irqsave(&failed_read_lock, flags);
> > +	if (list_empty(&failed_read_list))
> > +		WARN_ON_ONCE(!schedule_work(&failed_read_work));
> > +	list_add_tail(&fb->io_list, &failed_read_list);
> > +	spin_unlock_irqrestore(&failed_read_lock, flags);
> > +}
> > +
> > +static void iomap_read_end_io(struct bio *bio)
> > +{
> > +	if (bio->bi_status) {
> > +		struct iomap_failed_bio *fb = kzalloc_obj(*fb, GFP_ATOMIC);
> > +
> > +		if (fb) {
> > +			fb->bio = bio;
> > +			INIT_LIST_HEAD(&fb->io_list);
> > +			iomap_fail_buffered_read(fb);
> > +			return;
> > +		}
> > +	}
> > +
> > +	__iomap_read_end_io(bio);
> > +}
> > +
> >  static void iomap_bio_submit_read(struct iomap_read_folio_ctx *ctx)
> >  {
> >  	struct bio *bio = ctx->read_ctx;
> >