Using PTHREAD_PRIO_INHERIT causes panic in kern_umtx.c
Justin Teller
justin.teller at gmail.com
Mon Mar 9 12:02:13 PDT 2009
When I compile and run the attached program, it panics my system,
(FreeBSD CURRENT as of 2-20-09) with the following message:
panic: Assertion pi != NULL failed at /usr/src/sys/kern/kern_umtx: 1464
With the backtrace being:
Tracing pid 1079 tid 100045 td 0xffffff00037c8000
kdb_enter() at kdb_enter+0x40
panic() at panic+0x1ec
umtx_pi_adjust() at umtx_pi_adjust+0xfc8
umtx_pi_adjust() at umtx_pi_adjust+0x19bd
_umtx_unlock() at _umtx_unlock+0x2c41
_umtx_op() at _umtx_op+0x22
syscall() at syscall+0x1f4
Xfast_syscall() at Xfast_syscall+0xaa
--- syscall (454, FreeBSD ELF64, _umtx_op), rip = 0x4056ac, rsp =
0x7fffffbfef38, rbp = 0x80060b150 ---
This problem only shows up when I use PTHREAD_PRIO_INHERIT -- if I
change the line for pthread_mutexattr_setprotocol to
PTHREAD_PRIO_NONE, then it works fine. I've been trying to trace thru
the code to figure out where uq_pi_blocked should be setup, but I'm
not too familiar with the code so I haven't found where the problem
originates. How can I get PTHREAD_PRIO_INHERIT to work? And even if
the change is in user-space, it probably shouldn't be this easy to
panic the kernel :-)
-Justin
PS I'm reasonably certain that the most recent checkins (between now
and Feb 20th) wouldn't fix this, but if I'm wrong, just let me know!
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