RELENG_5 PAE panic
Robert Watson
rwatson at FreeBSD.org
Fri Jul 29 08:18:59 GMT 2005
On Thu, 28 Jul 2005, Frank McConnell wrote:
> --- begin paste ---
> Fatal trap 12: page fault while in kernel mode
> fault virtual address = 0x24
> fault code = supervisor read, page not present
> instruction pointer = 0x8:0xc03db1cf
> stack pointer = 0x10:0xeb328c64
> frame pointer = 0x10:0xeb328c78
> code segment = base 0x0, limit 0xfffff, type 0x1b
> = DPL 0, pres 1, def32 1, gran 1
> processor eflags = resume, IOPL = 0
> current process = 70 (pagedaemon)
> [thread pid 70 tid 100080 ]
> Stopped at 0xc03db1cf = propagate_priority+0x7f: movl 0x24(%eax),%eax
> db> trace
> Tracing pid 70 tid 100080 td 0xc6a89000
> propagate_priority(c6a89000,c0628280,c0636c60,c6a89000,c6cdaa82) at 0xc03db1cf = propagate_priority+0x7f
> turnstile_wait(c6a6f240,c0636c60,c6cdaa80) at 0xc03db84a = turnstile_wait + 0x266
> _mtx_lock_sleep(c0636c60,c6a89000,0,0,0) at 0xc03b4c25 = _mtx_lock_speed+0xad
> msleep(c0637104,c0636c60,44,c059aa74,1f4) at 0xc03c37ea = msleep+0x39a
> vm_pageout(0,eb328d38) at 0xc04fb0e4 = vm_pageout+0x280
> fork_exit(c04fae64,0,eb328d38) at 0xc03a8680 = fork_exit+0x74
> fork_trampoline() at 0xc0539d9c = fork_trampoline+0x8
> --- trap 0x1, eip = 0, esp = 0xeb328d6c, ebp = 0 ---
> db>
This appears to be a NULL pointer dereference in propagate_priotity().
Often a panic in propagate_priority is actually a symptom of a slightly
earlier problem which is discovered by propagate_priority when it trips
over, for example, a bad mutex. If you're set up with a serial port to
copy and paste debugging output, the output of 'ps' and 'show pcpu' for
each of the cpus (as well as 'show pcpu without a cpu argument) would be
helpful. It wouldn't hurt also to use gdb on a copy of the kernel with
debugging sybols to map 'vm_pageout+0x280' into a line number. Details on
these various activities can be found in the handbook.
Robert N M Watson
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