camcontrol eject -> panic: sleep on wchan with sleeping prohibited

[Harry Schmalzbauer]

 Hello,

HEAD panics reproducably if I eject cd-rom media:

Unread portion of the kernel message buffer:
panic: sleepq_add: td 0xfffff800035ad560 to sleep on wchan
0xfffff8000b015048 with sleeping prohibited
cpuid = 2
time = 1525970358
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
#2 0xffffffff803e6b79 in db_command (cmd_table=<value optimized out>) at
/usr/local/share/deploy-tools/HEAD/src/sys/ddb/db_command.c:481
#3 0xffffffff803e68f4 in db_command_loop () at
/usr/local/share/deploy-tools/HEAD/src/sys/ddb/db_command.c:534
#4 0xffffffff803e9b8f in db_trap (type=<value optimized out>,
code=<value optimized out>) at
/usr/local/share/deploy-tools/HEAD/src/sys/ddb/db_main.c:252
#5 0xffffffff80811253 in kdb_trap (type=3, code=-61456, tf=<value
optimized out>) at
/usr/local/share/deploy-tools/HEAD/src/sys/kern/subr_kdb.c:697
#6 0xffffffff80b0a83d in trap (frame=0xfffffe000048c500) at
/usr/local/share/deploy-tools/HEAD/src/sys/amd64/amd64/trap.c:601
#7 0xffffffff80ae709c in calltrap () at
/usr/local/share/deploy-tools/HEAD/src/sys/amd64/amd64/exception.S:230
#8 0xffffffff8081093b in kdb_enter (why=0xffffffff80c6eecf "panic",
msg=<value optimized out>) at cpufunc.h:65
#9 0xffffffff807cafc0 in vpanic (fmt=<value optimized out>,
ap=0xfffffe000048c670) at
/usr/local/share/deploy-tools/HEAD/src/sys/kern/kern_shutdown.c:852
#10 0xffffffff807cad70 in kassert_panic (fmt=<value optimized out>) at
/usr/local/share/deploy-tools/HEAD/src/sys/kern/kern_shutdown.c:749
#11 0xffffffff8081f538 in sleepq_add (wchan=0xfffff8000b015048,
lock=0xfffff8000b013cd0, wmesg=0xffffffff80c4d180 "cbwait", flags=0,
queue=0)
at /usr/local/share/deploy-tools/HEAD/src/sys/kern/subr_sleepqueue.c:319
#12 0xffffffff807d50f1 in _sleep (ident=<value optimized out>,
lock=<value optimized out>, priority=92, wmesg=0xffffffff80c4d180 "cbwait",
#13 0xffffffff802f4a7d in cam_periph_runccb (ccb=0xfffff8000b015000,
error_routine=0xffffffff8031ddd0 <cderror>, camflags=CAM_RETRY_SELTO,
sense_flags=3,
ds=0xfffff80003588000) at
/usr/local/share/deploy-tools/HEAD/src/sys/cam/cam_periph.c:1141
#14 0xffffffff8031d69a in cdcheckmedia (periph=0xfffff8000b11c100) at
/usr/local/share/deploy-tools/HEAD/src/sys/cam/scsi/scsi_cd.c:808
#15 0xffffffff80319cf5 in cdstrategy (bp=0xfffff800ccdd4300) at
/usr/local/share/deploy-tools/HEAD/src/sys/cam/scsi/scsi_cd.c:848
#16 0xffffffff8070e274 in g_disk_start (bp=<value optimized out>) at
/usr/local/share/deploy-tools/HEAD/src/sys/geom/geom_disk.c:478
#17 0xffffffff80712255 in g_io_schedule_down (tp=<value optimized out>)
at /usr/local/share/deploy-tools/HEAD/src/sys/geom/geom_io.c:893
#18 0xffffffff80712a7d in g_down_procbody (arg=<value optimized out>) at
/usr/local/share/deploy-tools/HEAD/src/sys/geom/geom_kern.c:111
#19 0xffffffff8078aa74 in fork_exit (callout=0xffffffff80712a10
<g_down_procbody>, arg=0x0, frame=0xfffffe000048cac0)
at /usr/local/share/deploy-tools/HEAD/src/sys/kern/kern_fork.c:1039
#20 0xffffffff80ae804e in fork_trampoline () at
/usr/local/share/deploy-tools/HEAD/src/sys/amd64/amd64/exception.S:971
#21 0x0000000000000000 in ?? ()
Current language: auto; currently minima

Since I see many geom/cam issues show up here at scsi@, I thought this
was the right place to report.
Please correct me if wrong.

Observed with r3333xx (HEAD from today and about two days back) –
haven't run HEAD before, so no indication of recent regression!

-Harry