Re: kern/58043: kernel crash in assert_sleepable() in -current, dk(4) driver?

[triaxx%NetBSD.org@localhost]

I have two kernels on this system: netbsd-GENERIC and 
netbsd-GOLIATH-noamdgpu.

Surprisingly, GOLIATH-noamdgpu crashes when GENERIC doesn't. The diff 
between both configurations is:

1c1
< ### START CONFIG FILE "/usr/src/sys/arch/amd64/conf/GENERIC"
---
> ### START CONFIG FILE 
"/home/triaxx/NetBSD/src/sys/arch/amd64/conf/GOLIATH-noamdgpu"
118,119c118,119
< #options      DEBUG           # expensive debugging checks/support
< #options      LOCKDEBUG       # expensive locking checks/support
---
> options       DEBUG           # expensive debugging checks/support
> options       LOCKDEBUG       # expensive locking checks/support
130,131c130,131
< #options      KGDB            # remote debugger
< #options      KGDB_DEVNAME="\"com\"",KGDB_DEVADDR=0x3f8,KGDB_DEVRATE=9600
---
> options       KGDB            # remote debugger
> options       KGDB_DEVNAME="\"com\"",KGDB_DEVADDR=0x3f8,KGDB_DEVRATE=9600
255c255
< #options      ACPIVERBOSE     # verbose ACPI configuration messages
---
> options       ACPIVERBOSE     # verbose ACPI configuration messages
461,462c461,462
< i915drmkms*   at pci? dev ? function ?
< intelfb*      at intelfbbus?
---
> #i915drmkms*  at pci? dev ? function ?
> #intelfb*     at intelfbbus?
464,465c464,465
< radeon*       at pci? dev ? function ?
< radeondrmkmsfb* at radeonfbbus?
---
> #radeon*      at pci? dev ? function ?
> #radeondrmkmsfb* at radeonfbbus?
470,471c470,471
< nouveau*      at pci? dev ? function ?
< nouveaufb*    at nouveaufbbus?
---
> #nouveau*     at pci? dev ? function ?
> #nouveaufb*   at nouveaufbbus?
1245c1245
< ### END CONFIG FILE "/usr/src/sys/arch/amd64/conf/GENERIC"
---
> ### END CONFIG FILE 
"/home/triaxx/NetBSD/src/sys/arch/amd64/conf/GOLIATH-noamdgpu"

> I have a system with:
>
>      $ dmesg -t | grep ccd
>      dk7 at wd1: "ccd0p0", 488397088 blocks at 40, type: ccd
>      dk8 at wd2: "ccd0p1", 488397088 blocks at 40, type: ccd
>      ccd0: Interleaving 2 components (63 block interleave)
>      ccd0: /dev/dk7 (488397042 blocks)
>      ccd0: /dev/dk8 (488397042 blocks)
>      ccd0: total 976794084 blocks
>      ccd0: GPT GUID: 546b7b1d-bf71-46a2-9788-226ebaf7ae2d
>      dk12 at ccd0: "ccd0", 976794008 blocks at 40, type: ffs
>
> The patch fixes the issue with the kernel that crashes on this system.
>
> > I've already converted my config to raid0 instead of ccd, so I am sorry
> > that I am unable to test the patch.  :-(
> >
> > On Mon, 18 Mar 2024, J. Hannken-Illjes wrote:
> >
> > > The following reply was made to PR kern/58043; it has been noted by 
> > > GNATS.
> > >
> > > From: "J. Hannken-Illjes" <hannken%mailbox.org@localhost>
> > > To: gnats-bugs%netbsd.org@localhost
> > > Cc:
> > > Subject: Re: kern/58043: kernel crash in assert_sleepable() in 
> > > -current, dk(4)
> > > driver?
> > > Date: Mon, 18 Mar 2024 10:52:09 +0100
> > >
> > > Paul,
> > >
> > > please try the attached patch -- if it prevents assert_sleepable() to 
> > > fire
> > > it is the call to CCD_GETBUF() aka. pool_cache_get(ccd_cache, PR_WAITOK)
> > > from softint context that has to be fixed.
> > >
> > > --
> > > J. Hannken-Illjes - hannken%mailbox.org@localhost <mailto:hannken%mailbox.org@localhost>
> > >
> > > ccd_defer
> > >
> > > Always defer requests to the helper thread so ccdstart() doesn't
> > > get called from softint anymore.
> > >
> > > diff -r 8b8d2498ffd9 -r 2ec4e85f1120 sys/dev/ccd.c
> > > --- sys/dev/ccd.c
> > > +++ sys/dev/ccd.c
> > > @@ -777,17 +777,10 @@ ccdstrategy(struct buf *bp)
> > >          return;
> > >      }
> > >
> > > -    /* Defer to thread if system is low on memory. */
> > > +    /* Always defer to thread. */
> > >      bufq_put(cs->sc_bufq, bp);
> > > -    if (__predict_false(ccdbackoff(cs))) {
> > > -        mutex_exit(cs->sc_iolock);
> > > -#ifdef DEBUG
> > > -         if (ccddebug & CCDB_FOLLOW)
> > > -             printf("ccdstrategy: holding off on I/O\n");
> > > -#endif
> > > -        return;
> > > -    }
> > > -    ccdstart(cs);
> > > +    cv_broadcast(&cs->sc_push);
> > > +    mutex_exit(cs->sc_iolock);
> > >  }
> > >
> > >  static void