On Mon, 9 Sep 2013 11:22:29 -0400 John Baldwin <[email protected]> wrote: > > > Fatal trap 12: page fault while in kernel mode > > cpuid = 0; apic id = 00 > > fault virtual address = 0x0 > > fault code = supervisor write data, page not present > > instruction pointer = 0x20:0xffffffff80ceddcd > > stack pointer = 0x28:0xffffff80dbfe25e0 > > frame pointer = 0x28:0xffffff80dbfe2660 > > code segment = base 0x0, limit 0xfffff, type 0x1b > > = DPL 0, pres 1, long 1, def32 0, gran 1 > > processor eflags = interrupt enabled, resume, IOPL = 0 > > current process = 52022 (firefox) > > trap number = 12 > > panic: page fault > > cpuid = 0 > > KDB: stack backtrace: > > #0 0xffffffff80947986 at kdb_backtrace+0x66 > > #1 0xffffffff8090d9ae at panic+0x1ce > > #2 0xffffffff80cf1db0 at trap_fatal+0x290 > > #3 0xffffffff80cf2111 at trap_pfault+0x211 > > #4 0xffffffff80cf26c4 at trap+0x344 > > #5 0xffffffff80cdb9f3 at calltrap+0x8 > > #6 0xffffffff80b797a7 at vm_fault_hold+0x1b87 > > This is where the NULL pointer is. Frame 9 (listed below) is above this. > > > (kgdb) list *0xffffffff80ceddcd > > 0xffffffff80ceddcd is in pmap_enter (../../../amd64/amd64/pmap.c:3577). > > 3572 if ((m->oflags & VPO_UNMANAGED) == 0) { > > 3573 newpte |= PG_MANAGED; > > 3574 pv = get_pv_entry(pmap, &lock); > > 3575 pv->pv_va = va; > > 3576 CHANGE_PV_LIST_LOCK_TO_PHYS(&lock, pa); > > 3577 TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list); > > 3578 if ((newpte & PG_RW) != 0) > > 3579 vm_page_aflag_set(m, PGA_WRITEABLE); > > 3580 } > > 3581 > > So it seems like pv_list of a page might be busted? Can you try looking at > the disassembly to see if you can find 'm' in one of the registers? >
Sure, here you go...
(kgdb) print m
$1 = 0xfffffe00b260b430
(kgdb) print m->md.pv_list
$4 = {tqh_first = 0x0, tqh_last = 0x0}
(kgdb) print pv
$2 = 0xfffffe0095088ad8
(kgdb) print pv_list
No symbol "pv_list" in current context.
(kgdb) info registers
rax 0x1 1
rbx 0xfffffe0095088ae0 -2196522890528
rcx 0x0 0
rdx 0xfffffe00b260b430 -2196030573520
rsi 0x0 0
rdi 0x153 339
rbp 0xffffff80dbfe2660 0xffffff80dbfe2660
rsp 0xffffff80dbfe25f0 0xffffff80dbfe25f0
r8 0x0 0
r9 0x827689000 35020902400
r10 0x63 99
r11 0xfffffe00b260b430 -2196030573520
r12 0x47f 1151
r13 0xfffffe00862458d8 -2196772726568
r14 0xfffffe0092907448 -2196564315064
r15 0xfffffe0095088ad8 -2196522890536
rip 0xffffffff80ceddcd 0xffffffff80ceddcd <pmap_enter+1709>
eflags 0x10202 66050
cs 0x20 32
ss 0x0 0
ds 0x0 0
es 0x0 0
fs 0x0 0
gs 0x0 0
signature.asc
Description: PGP signature
