panic: locking xyz against myself (linux DRM?!)

Timo Buhrmester

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Jul 25, 2015, 4:43:14 PM7/25/15

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For a while now, I'm getting the occasional panic which I can't directly reproduce, but it seems to correlate with long and/or memory- and/or video-intense firefox sessions.

This is a recent -current (7.99.20 on amd64, although the problem exists as of at least 7.99.10, likely earlier too), my (onboard) video chip is
> radeon0 at pci1 dev 5 function 0: vendor 1002 product 9614 (rev. 0x00)
all with
> radeondrmkmsfb0 at radeon0
> radeondrmkmsfb0: framebuffer at 0xffff800046148000, size 1280x1024, depth 32, stride 5120

Besides that, I'm using Xorg from pkgsrc-2015Q2 (i.e. X11_TYPE=modular)

Now, whenever the system is up for a few days, and I didn't think of restarting firefox for a while, it eventually crashes with:
> panic: kernel diagnostic assertion "((mutex->wwm_state != WW_OWNED) || (mutex->wwm_u.owner != curlwp))" failed: file "/usr/src/sys/external/bsd/drm2/linux/linux_ww_mutex.c", line 760 locking 0xfffffe804fc70220 against myself: 0xfffffe811c5b2840
> fatal breakpoint trap in supervisor mode
> trap type 1 code 0 rip ffffffff80193685 cs 8 rflags 246 cr2 7f7ff7e43000 ilevel 8 rsp fffffe8041791ac0
> curlwp 0xfffffe811c5b2840 pid 1237.1 lowest kstack 0xfffffe804178e2c0
> Stopped in pid 1237.1 (Xorg) at netbsd:breakpoint+0x5: leave
> breakpoint() at netbsd:breakpoint+0x5
> vpanic() at netbsd:vpanic+0x13c
> kern_assert() at netbsd:kern_assert+0x4f
> linux_ww_mutex_trylock() at netbsd:linux_ww_mutex_trylock+0xc1
> ttm_bo_uvm_fault() at netbsd:ttm_bo_uvm_fault+0x69
> radeon_ttm_fault() at netbsd:radeon_ttm_fault+0x6a
> uvm_fault_internal() at netbsd:uvm_fault_internal+0x828
> trap() at netbsd:trap+0x32a
> --- trap (number 6) ---
> 7f7ff002e4ed:
> db{1}>

Any ideas? Does anyone else have the same problem?

I can extract information from the crash dump if required.

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matthew green

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Jul 25, 2015, 5:48:49 PM7/25/15

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> Now, whenever the system is up for a few days, and I didn't think of restarting firefox for a while, it eventually crashes with:
> > panic: kernel diagnostic assertion "((mutex->wwm_state != WW_OWNED) || (mutex->wwm_u.owner != curlwp))" failed: file "/usr/src/sys/external/bsd/drm2/linux/
> linux_ww_mutex.c", line 760 locking 0xfffffe804fc70220 against myself: 0xfffffe811c5b2840

[ ... ]

>
> Any ideas? Does anyone else have the same problem?
>
> I can extract information from the crash dump if required.

this is PR 49862 that we don't have any good idea about yet. :-(

i've seen it 4 times. once a while ago, then 3 times in the
space of an hour (all while scrolling around in google maps
inside firefox.)

.mrg.

Taylor R Campbell

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Jul 25, 2015, 6:43:35 PM7/25/15

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Date: Sun, 26 Jul 2015 07:48:22 +1000
from: matthew green <m...@eterna.com.au>

> Now, whenever the system is up for a few days, and I didn't think of restarting firefox for a while, it eventually crashes with:
> > panic: kernel diagnostic assertion "((mutex->wwm_state != WW_OWNED) || (mutex->wwm_u.owner != curlwp))" failed: file "/usr/src/sys/external/bsd/drm2/linux/
> linux_ww_mutex.c", line 760 locking 0xfffffe804fc70220 against myself: 0xfffffe811c5b2840
[ ... ]
>
> Any ideas? Does anyone else have the same problem?
>
> I can extract information from the crash dump if required.

this is PR 49862 that we don't have any good idea about yet. :-(

I've been offering the attached patch to try to debug the source of
the problem before the symptom you described happens. I haven't
gotten any diagnostics back from anyone yet. If you can, please try
it out and let me know.

cheap-lockdebug.patch

Timo Buhrmester

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Jul 25, 2015, 9:56:10 PM7/25/15

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> I've been offering the attached patch to try to debug the source of
> the problem before the symptom you described happens. I haven't
> gotten any diagnostics back from anyone yet. If you can, please try
> it out and let me know.

I believe we're already discussing this on IRC, but for the record, with your patch and LOCKDEBUG I get:

panic: kernel diagnostic assertion "((mutex->wwm_state != WW_OWNED) || (mutex->wwm_u.owner != curlwp))" failed: file "/usr/src/sys/external/bsd/drm2/linux/linux_ww_mutex.c", line 760 locking 0xfffffe8084178220 against myself: 0xfffffe811d915700

fatal breakpoint trap in supervisor mode

trap type 1 code 0 rip ffffffff8028be15 cs 8 rflags 246 cr2 7f7ff2e62000 ilevel 8 rsp fffffe804175dad8
curlwp 0xfffffe811d915700 pid 2288.1 lowest kstack 0xfffffe804175a2c0
Stopped in pid 2288.1 (Xorg) at netbsd:breakpoint+0x5: leave
db{0}> bt

breakpoint() at netbsd:breakpoint+0x5
vpanic() at netbsd:vpanic+0x13c
kern_assert() at netbsd:kern_assert+0x4f

linux_ww_mutex_trylock() at netbsd:linux_ww_mutex_trylock+0xed

ttm_bo_uvm_fault() at netbsd:ttm_bo_uvm_fault+0x69
radeon_ttm_fault() at netbsd:radeon_ttm_fault+0x6a
uvm_fault_internal() at netbsd:uvm_fault_internal+0x828

trap() at netbsd:trap+0x249

--- trap (number 6) ---
7f7ff002e4ed:

db{0}>

Cheers