Possible scheduler (SCHED_ULE) bug?

[Jaime Bozza]

From: Kostik Belousov [mailto:kostikbel at gmail.com]
> Can you look up the source line for kern_sendfile+0x90d in your
> kernel ? Do kgdb kernel.debug, then execute "list *(kern_sendfile+0x90d)".

In my case, it was kern_sendfile+0x6ad (rebuilt with RELENG_7 this weekend).

Here's the output:

(kgdb) list *(kern_sendfile+0x6ad)
0xc0855fdd is in kern_sendfile (atomic.h:160).
155     static __inline int
156     atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
157     {
158             u_char res;
159
160             __asm __volatile(
161             "       " MPLOCKED "            "
162             "       cmpxchgl %2,%1 ;        "
163             "       sete    %0 ;            "
164             "1:                             "

Not much to go on there.  I posted a backtrace in a previous email, but the relevant sections (I think) are:

#14 0xc0855fdd in kern_sendfile (td=0xc771db40, uap=0xc72e2cfc, hdr_uio=0x0, trl_uio=0x0, compat=0) at atomic.h:160
#15 0xc0856d31 in do_sendfile (td=0xc771db40, uap=0xc72e2cfc, compat=0) at /usr/src/sys/kern/uipc_syscalls.c:1775
#16 0xc0856dd3 in sendfile (td=0xc771db40, uap=0xc72e2cfc) at /usr/src/sys/kern/uipc_syscalls.c:1746
#17 0xc0b01365 in syscall (frame=0xc72e2d38) at /usr/src/sys/i386/i386/trap.c:1094
#18 0xc0ae5960 in Xint0x80_syscall () at /usr/src/sys/i386/i386/exception.s:262
#19 0x00000033 in ?? ()
Previous frame inner to this frame (corrupt stack?)

I'm still going to test the specific boundary, but if there's more information I can give, let me know!

Jaime