Re: panic: vm_fault: fault on nofault entry, addr: fffffe00873d8000

Konstantin Belousov <kostikbel_at_gmail.com> wrote:

> On Sun, Dec 06, 2015 at 11:45:32AM +0100, Fabian Keil wrote:
> > I got the following panic while trying to import a ZFS pool from a
> > geli-encrypted memory disk backed by a file located on a msdosfs partition:  
> I smiled.

I occasionally use this somewhat non-standard setup to store redundant
backups on a media player whose bootloader may not be prepared to deal
with multiple partitions ...

> > (kgdb) where
> > #0  doadump (textdump=0) at pcpu.h:221
> > #1  0xffffffff80314c1b in db_dump (dummy=<value optimized out>, dummy2=false, dummy3=0, dummy4=0x0) at /usr/src/sys/ddb/db_command.c:533
> > #2  0xffffffff80314a0e in db_command (cmd_table=0x0) at /usr/src/sys/ddb/db_command.c:440
> > #3  0xffffffff803147a4 in db_command_loop () at /usr/src/sys/ddb/db_command.c:493
> > #4  0xffffffff803172ab in db_trap (type=<value optimized out>, code=0) at /usr/src/sys/ddb/db_main.c:251
> > #5  0xffffffff805dfe33 in kdb_trap (type=3, code=0, tf=<value optimized out>) at /usr/src/sys/kern/subr_kdb.c:654
> > #6  0xffffffff80879bc7 in trap (frame=0xfffffe009444a240) at /usr/src/sys/amd64/amd64/trap.c:549
> > #7  0xffffffff8085eb77 in calltrap () at /usr/src/sys/amd64/amd64/exception.S:234
> > #8  0xffffffff805df51b in kdb_enter (why=0xffffffff8096c7fb "panic", msg=0x32 <Address 0x32 out of bounds>) at cpufunc.h:63
> > #9  0xffffffff8059bbdf in vpanic (fmt=<value optimized out>, ap=<value optimized out>) at /usr/src/sys/kern/kern_shutdown.c:750
> > #10 0xffffffff8059ba33 in panic (fmt=0x0) at /usr/src/sys/kern/kern_shutdown.c:688
> > #11 0xffffffff8082ffb5 in vm_fault_hold (map=<value optimized out>, vaddr=<value optimized out>, fault_type=<value optimized out>, fault_flags=<value optimized out>, m_hold=<value optimized out>)
> >     at /usr/src/sys/vm/vm_fault.c:332
> > #12 0xffffffff8082de18 in vm_fault (map=0xfffff80002000000, vaddr=<value optimized out>, fault_type=2 '\002', fault_flags=0) at /usr/src/sys/vm/vm_fault.c:277
> > #13 0xffffffff8087a33a in trap_pfault (frame=0xfffffe009444a8e0, usermode=0) at /usr/src/sys/amd64/amd64/trap.c:734
> > #14 0xffffffff80879bde in trap (frame=0xfffffe009444a8e0) at /usr/src/sys/amd64/amd64/trap.c:435
> > #15 0xffffffff8085eb77 in calltrap () at /usr/src/sys/amd64/amd64/exception.S:234
> > #16 0xffffffff80877d5a in bcopy () at /usr/src/sys/amd64/amd64/support.S:118
> > #17 0xffffffff805f64e8 in uiomove_faultflag (cp=<value optimized out>, n=<value optimized out>, uio=0xfffffe009444aae0, nofault=<value optimized out>) at /usr/src/sys/kern/subr_uio.c:208
> > #18 0xffffffff8046236f in msdosfs_read (ap=<value optimized out>) at /usr/src/sys/fs/msdosfs/msdosfs_vnops.c:596
> > #19 0xffffffff808feb20 in VOP_READ_APV (vop=<value optimized out>, a=<value optimized out>) at vnode_if.c:930
> > #20 0xffffffff8039bf3a in mdstart_vnode (sc=0xfffff8004c7ce000, bp=0xfffff80028fc81f0) at vnode_if.h:384  
> From the frame 20, do 'p *bp' in kgdb and mail the result.  Do you have
> any non-standard values for buffer cache knobs, esp. for MAXPHYS ?

(kgdb) p *bp
$1 = {bio_cmd = 1 '\001', bio_flags = 16 '\020', bio_cflags = 0 '\0', bio_pflags = 0 '\0', bio_dev = 0x0, bio_disk = 0x0, bio_offset = 0, bio_bcount = 0, 
  bio_data = 0xfffffe0077d94000 <Address 0xfffffe0077d94000 out of bounds>, bio_ma = 0xfffff8000275bc00, bio_ma_offset = 960, bio_ma_n = 33, bio_error = 0, bio_resid = 0, 
  bio_done = 0xffffffff804e51d0 <g_std_done>, bio_driver1 = 0x0, bio_driver2 = 0x0, bio_caller1 = 0x0, bio_caller2 = 0x0, bio_queue = {tqe_next = 0x0, tqe_prev = 0xfffff8004c7ce018}, bio_attribute = 0x0, 
  bio_from = 0xfffff80010131d80, bio_to = 0xfffff800694f2a00, bio_length = 131072, bio_completed = 0, bio_children = 0, bio_inbed = 0, bio_parent = 0xfffff8000628bd90, bio_t0 = {sec = 33029, 
    frac = 13163670047247984455}, bio_task = 0, bio_task_arg = 0x0, bio_classifier1 = 0x0, bio_classifier2 = 0x0, bio_pblkno = 0}
 
I don't use non-standard values for MAXPHYS or other buffer cache settings.

Fabian