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Re: kern/60029: panic: cpu0: softints stuck for 16 seconds



The following reply was made to PR kern/60029; it has been noted by GNATS.

From: Thomas Klausner <wiz%netbsd.org@localhost>
To: Taylor R Campbell <riastradh%netbsd.org@localhost>
Cc: NetBSD bugtracking <gnats-bugs%netbsd.org@localhost>
Subject: Re: kern/60029: panic: cpu0: softints stuck for 16 seconds
Date: Sun, 22 Feb 2026 20:48:39 +0100

 On Sun, Feb 22, 2026 at 07:24:59PM +0100, Taylor R Campbell wrote:
 > > Date: Sun, 22 Feb 2026 14:02:33 +0100
 > > From: Thomas Klausner <wiz%netbsd.org@localhost>
 > > 
 > > 0    >  935 7  16     40200   ffff8fb6be107400           pgdaemon
 > > [...]
 > > 0    >    4 7   0       200   ffff8fc60b25f800          softbio/0
 > 
 > These two look suspicious.
 
 How do you figure?
 
 > Now, I think the stack traces won't be reliable because the threads in
 > question are running on the CPU (so we really want `mach cpu N' and
 > `bt', but PR bin/58010: crash(8) doesn't support `mach cpu N' to
 > examine registers/stack of other CPUs), but just in case, here's the
 > stack trace for softbio/0:
 > 
 > > crash> bt/a ffff8fc60b25f800
 > > trace: pid 0 lid 4 at 0xffffa72469e83fa0
 > > uvm_aio_aiodone() at uvm_aio_aiodone+0xbe
 > > dkiodone() at dkiodone+0xa8
 > > lddone() at lddone+0xf
 > > nvme_q_complete() at nvme_q_complete+0xf2
 > > softint_dispatch() at softint_dispatch+0x112
 > 
 > If you have netbsd.gdb, can you get output of `info line
 > *(uvm_aio_aiodone+0xbe)' in gdb from it?
 
 Sure:
 
 (gdb) info line *(uvm_aio_aiodone+0xbe)
 Line 528 of "/usr/src/sys/uvm/uvm_pager.c" starts at address 0xffffffff80dd7549 <uvm_aio_aiodone+190> and ends at 0xffffffff80dd7557 <uvm_aio_aiodone+204>.
 
 
 > And can you get the stack trace for pgdaemon too?
 > 
 > crash> bt/a ffff8fb6be107400
 
 crash> bt/a ffff8fb6be107400
 trace: pid 0 lid 935 at 0xffffa7247baabee0
 pager_map_wanted_lock() at uvmpd_lock
 uvm_pageout() at uvm_pageout+0x549
 
 
 > My guess is the softbio thread might be waiting for this lock:
 > 
 >     528 	if (write && (bp->b_cflags & BC_AGE) != 0) {
 >  -> 529 		mutex_enter(bp->b_objlock);
 >     530 		vwakeup(bp);
 >     531 		mutex_exit(bp->b_objlock);
 >     532 	}
 > 
 > https://nxr.netbsd.org/xref/src/sys/uvm/uvm_pager.c?r=1.131#529
 > 
 > This is probably either buffer_lock or vp->v_interlock for some vnode.
 > In case it's buffer_lock, can you show this?
 > 
 > crash> x/Lx buffer_lock
 
 crash> x/Lx buffer_lock
 buffer_lock:    0
 
 
 > Since they're not _sleeping_ on a wait-channel, whoever holds the lock
 > (whether it's buffer_lock or vp->v_interlock) is probably on running
 > on another CPU.  That narrows it down to:
 > 
 > PID     LID S CPU     FLAGS       STRUCT LWP *               NAME WAIT
 > 20857>20857 7  17   8060000   ffff8fa8dbeac000                moc
 > 2482 > 2482 7  23   8060000   ffff8fb50065c800                moc
 > 26437>26437 7   9   8060000   ffff8fb50065c000                moc
 > 12057>12057 7  31   8020000   ffff8fbf931ab000                moc
 > 18565>18565 7  21   8060000   ffff8fc129ed9c00                moc
 > 12544>12544 7  22   8060000   ffff8fc129ed9000                moc
 > 13508>13508 7   2   8060000   ffff8fb908ee8800                moc
 > 3522 > 3522 7  20   8020000   ffff8fc1d885ac00                moc
 > 23657>23657 7   3   8020000   ffff8fb90950c800                moc
 > 3031 > 3031 7  28   8060000   ffff8fb10d2b3400                moc
 > 13759>13759 7   5   8020000   ffff8faac5fec000                moc
 > 25301>25301 7  15   8060000   ffff8fc2d6fb1400                moc
 > 13934>13934 7  14   8060000   ffff8fb8f1b68800                moc
 > 9619 > 9619 7  11   8060000   ffff8fb8f1b68000                moc
 > 11474>11474 7  13   8020000   ffff8fb7c17d2c00                moc
 > 23339>23339 7  29   8060000   ffff8fb7b9e4cc00                moc
 > 5510 > 5510 7  10   8060000   ffff8fc36cf3ec00                moc
 > 2567 > 2567 7  27   8020000   ffff8fc331b27c00                moc
 > 29924>29924 7   4   8020000   ffff8fc561094c00                moc
 > 20557>20557 7  26   8020000   ffff8fc561094800                moc
 > 23674>23674 7   6   8060000   ffff8fc38a557000                moc
 > 27935>27935 7  25   8060000   ffff8faaa08c1000                moc
 > 19811>19811 7   7   8060000   ffff8fbdc9009800                moc
 > 14383>14383 7  18   8060000   ffff8fbac25c2000                moc
 > 19788>19788 7  19   8060000   ffff8fc08f854c00                moc
 > 11290>11290 7  24   8060000   ffff8fb0ea2d1800                moc
 > 28134>28134 7  30   8020000   ffff8fc2010df800                moc
 > 27882>27882 7   8   8060000   ffff8fbd4892ac00                moc
 > 21709>21709 7  12   8060000   ffff8fb7cd8e5400                moc
 > 29702>29702 7   1   8020000   ffff8fb90a69dc00                moc
 > 0    >  935 7  16     40200   ffff8fb6be107400           pgdaemon
 > 0    >    4 7   0       200   ffff8fc60b25f800          softbio/0
 > 
 > Could try getting the stack traces for the moc processes but they're
 > probably in userland without any locks held...
 
 Throws a lot of errors, but here is the output:
 
 bt/a ffff8fa8dbeac000
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(40000029596bc18)
 crash: kvm_read(0x40000029596bc18, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 20857 lid 20857 at 0x40000029596bc10
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fb50065c800
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 2482 lid 2482 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fb50065c000
 
 crash: _kvm_kvatop(0)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 26437 lid 26437 at 0x0
 0:
 
 bt/a ffff8fbf931ab000
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 12057 lid 12057 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fc129ed9c00
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(95929c78)
 crash: kvm_read(0x95929c78, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 18565 lid 18565 at 0x95929c70
 __kernel_end() at 0
 
 bt/a ffff8fc129ed9000
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 12544 lid 12544 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fb908ee8800
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 13508 lid 13508 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fc1d885ac00
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 3522 lid 3522 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fb90950c800
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(945e4c78)
 crash: kvm_read(0x945e4c78, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 23657 lid 23657 at 0x945e4c70
 __kernel_end() at 0
 
 bt/a ffff8fb10d2b3400
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 3031 lid 3031 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8faac5fec000
 
 crash: _kvm_kvatop(0)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 13759 lid 13759 at 0xffffa724957e9cd0
 uvmfault_promote() at uvmfault_promote+0x4bb
 uvm_fault_internal() at uvm_fault_internal+0xd5a
 trap() at trap+0x46b
 --- trap (number 6) ---
 6fbeee905c3f:
 
 bt/a ffff8fc2d6fb1400
 
 crash: _kvm_kvatop(0)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 25301 lid 25301 at 0xffffa7247f844cd0
 uvmfault_promote() at uvmfault_promote+0x4bb
 uvm_fault_internal() at uvm_fault_internal+0xd5a
 trap() at trap+0x46b
 --- trap (number 6) ---
 f91581:
 
 bt/a ffff8fb8f1b68800
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 13934 lid 13934 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fb8f1b68000
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 9619 lid 9619 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fb7c17d2c00
 
 crash: _kvm_kvatop(0)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 11474 lid 11474 at 0xffffa72564f3aff0
 trap() at trap+0x46b
 --- trap (number 6) ---
 137dee:
 
 bt/a ffff8fb7b9e4cc00
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 23339 lid 23339 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fc36cf3ec00
 
 crash: _kvm_kvatop(0)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 5510 lid 5510 at 0xffff8fb848e1eb28
 __kernel_end() at 0
 
 bt/a ffff8fc331b27c00
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 2567 lid 2567 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fc561094c00
 
 crash: _kvm_kvatop(0)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 29924 lid 29924 at 0xffffa7249535bcd0
 uvmfault_promote() at uvmfault_promote+0x4bb
 uvm_fault_internal() at uvm_fault_internal+0xd5a
 trap() at trap+0x46b
 --- trap (number 6) ---
 f2363f:
 
 bt/a ffff8fc561094800
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(7d8a1c78)
 crash: kvm_read(0x7d8a1c78, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 20557 lid 20557 at 0x7d8a1c70
 __kernel_end() at 0
 
 bt/a ffff8fc38a557000
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(95274c78)
 crash: kvm_read(0x95274c78, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 23674 lid 23674 at 0x95274c70
 __kernel_end() at 0
 
 bt/a ffff8faaa08c1000
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 27935 lid 27935 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fbdc9009800
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 19811 lid 19811 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fbac25c2000
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 14383 lid 14383 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fc08f854c00
 
 crash: _kvm_kvatop(0)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 19788 lid 19788 at 0xffffa72480c14cd0
 uvmfault_promote() at uvmfault_promote+0x4bb
 uvm_fault_internal() at uvm_fault_internal+0xd5a
 trap() at trap+0x46b
 --- trap (number 6) ---
 d0bdee:
 
 bt/a ffff8fb0ea2d1800
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 11290 lid 11290 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fc2010df800
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(80c6bc78)
 crash: kvm_read(0x80c6bc78, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 28134 lid 28134 at 0x80c6bc70
 __kernel_end() at 0
 
 bt/a ffff8fbd4892ac00
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(81364c78)
 crash: kvm_read(0x81364c78, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 27882 lid 27882 at 0x81364c70
 __kernel_end() at 0
 
 bt/a ffff8fb7cd8e5400
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(400000200000008)
 crash: kvm_read(0x400000200000008, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 21709 lid 21709 at 0x400000200000000
 _KERNEL_OPT_NCOM_PUC() at _KERNEL_OPT_NCOM_PUC+0x5
 
 bt/a ffff8fb90a69dc00
 
 crash: _kvm_kvatop(0)
 crash: _kvm_kvatop(7d942c78)
 crash: kvm_read(0x7d942c78, 8): invalid translation (invalid level 4 PDE)
 Crash version 11.99.5, image version 11.99.5.
 Kernel compiled without options LOCKDEBUG.
 System panicked: cpu0: softints stuck for 16 seconds
 Backtrace from time of crash is available.
 trace: pid 29702 lid 29702 at 0x7d942c70
 __kernel_end() at 0
 
 
 Cheers,
  Thomas
 


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