Date: Tue, 10 Mar 2009 15:13:53 +0800 From: David Xu <davidxu@freebsd.org> To: Justin Teller <justin.teller@gmail.com> Cc: "freebsd-current@freebsd.org" <freebsd-current@freebsd.org> Subject: Re: Using PTHREAD_PRIO_INHERIT causes panic in kern_umtx.c Message-ID: <49B61331.4050106@freebsd.org> In-Reply-To: <c47019cc0903091355q2273d1fft715cd47cedab1d3d@mail.gmail.com> References: <3561C827-66BD-4B3F-A3D4-97C4C06884B4@gmail.com> <c47019cc0903091355q2273d1fft715cd47cedab1d3d@mail.gmail.com>
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Justin Teller wrote: > On Mon, Mar 9, 2009 at 12:02 PM, Justin Teller <justin.teller@gmail.com>wrote: > >> 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 >> There is a bug about NULL pointer, please try the patch, it also fixes a possible wake-up race. http://people.freebsd.org/%7Edavidxu/patch/kern_umtx_prio.patch David Xu
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