Re: memcpy of struct buf, or similar?

[Simon Burge <simonb%NetBSD.org@localhost>]

Simon Burge wrote:

> Simon Burge wrote:
> 
> > Chris Gilbert wrote:
> > 
> > > Simon Burge wrote:
> > > > Andrew Doran wrote:
> > > > 
> > > >> I am trying to fix PR 38761.  [ ... ]
> > > > 
> > > > FWIW, just sticking a
> > > > 
> > > >         KASSERT(mutex_owned(&bufcache_lock));
> > > > 
> > > > before each time b_cflags is modified fails to reach single user when it
> > > > hits genfs_getpages():
> > > > 
> > > > [ ... ]
> 
> All modifications of b_cflags are checked with the above
> KASSERT except kern/vfs_bio.c:nestiobuf_setup() and
> miscfs/genfs/genfs_io.c:genfs_getpages() and I've still ended
> up with one process in biowait, another in biolock and a bunch
> in tstile.

My last for the night...  With Andy's patched biowait()/biodone() and
the above KASSERTS, I fairly quickly got while doing a build:

panic: WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
kernel diagnostic assertion "cv_has_waiters(&bp->b_done)" failed: file 
"../../../../kern/vfs_bio.c", line 1553WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0

WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
fatal breakpoint trapWARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
 in supervisor mode
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
trap type 1 code 0 rip ffffffff8050bde5 cs 8 rflags 246 cr2  7f7ffdae8020 cpl 3 
rsp ffff800064fc4bb0
Stopped in pid 0.4 (system) at  netbsd:breakpoint+0x5:  leave
db{0}> bt
breakpoint() at netbsd:breakpoint+0x5
panic() at netbsd:panic+0x260
__kernassert() at netbsd:__kernassert+0x2d
biodone2() at netbsd:biodone2+0x136
biointr() at netbsd:biointr+0x3c
softint_dispatch() at netbsd:softint_dispatch+0xd3
db{0}> mac cpu 1
using CPU 1
db{0}> bt       
__cpu_simple_lock() at netbsd:__cpu_simple_lock+0xc
db{0}> mac cpu 2
using CPU 2
db{0}> bt       
__cpu_simple_lock() at netbsd:__cpu_simple_lock+0x13
db{0}> mac cpu 3
using CPU 3
db{0}> bt       
x86_mwait() at netbsd:x86_mwait+0xd
idle_loop() at netbsd:idle_loop+0x176
Bad frame pointer: 0xffff80006463c420
db{0}> mac cpu 4
using CPU 4
db{0}> bt       
__cpu_simple_lock() at netbsd:__cpu_simple_lock+0x13
alltraps() at netbsd:alltraps+0x1a9
uiomove() at netbsd:uiomove+0x63
ubc_uiomove() at netbsd:ubc_uiomove+0xd2
ffs_read() at netbsd:ffs_read+0x410
VOP_READ() at netbsd:VOP_READ+0x66
vn_read() at netbsd:vn_read+0x9f
dofileread() at netbsd:dofileread+0x80
sys_read() at netbsd:sys_read+0x72
syscall() at netbsd:syscall+0x9a
db{0}> mac cpu 5
using CPU 5
db{0}> bt       
bus_space_read_stream_1() at netbsd:bus_space_read_stream_1+0xe
cnputc() at netbsd:cnputc+0x2a
putchar() at netbsd:putchar+0x139
kprintf() at netbsd:kprintf+0x3ea
printf() at netbsd:printf+0xcd
db{0}> mac cpu 6 
using CPU 6
db{0}> bt       
__cpu_simple_lock() at netbsd:__cpu_simple_lock+0x13
db{0}> mac cpu 7
using CPU 7
db{0}> bt       
__cpu_simple_lock() at netbsd:__cpu_simple_lock+0x13

Simon.

ps: Two unrelated things.  A "show all backtraces" command in ddb that
iterates over all CPUs might be useful!  If anyone knows how to teach
DDB in amd64 to show function arguments I'm all ears.