Re: kern/41974: panic in cpu_in_cksum / likely NFS issue

["Greg A. Woods" <woods%planix.ca@localhost>]

The following reply was made to PR kern/41974; it has been noted by GNATS.

From: "Greg A. Woods" <woods%planix.ca@localhost>
To: NetBSD GNATS <gnats-bugs%NetBSD.org@localhost>
Cc: Joerg Sonnenberger <joerg%britannica.bec.de@localhost>,
    NetBSD GNATS Administrator <gnats-admin%NetBSD.org@localhost>
Subject: Re: kern/41974: panic in cpu_in_cksum / likely NFS issue
Date: Tue, 24 Feb 2015 10:11:28 -0800

 Joerg asked:
 >=20
 > Can you be more specific about what uvm_fault panics you see?
 
 Sorry, but they're just very much like the ones reported in the PR.
 
 They are apparently from a fault in cpu_in_cksum(), and any attempt to
 print a full stack trace causes another fault to happen in ddb, and the
 system needs a hard reset if you try to dump or sync or reboot with sync
 from ddb.  "reboot 0x4" works of course, albeit with the same loss to
 the mounted filesystems as a hard reset.
 
 Here's a copy of a couple of different crashes from my console log.
 
 uvm_fault(0xffffffff80d5bd80, 0xffff8001806fa000, 1) -> e
 fatal page fault in supervisor mode
 trap type 6 code 0 rip ffffffff80571b65 cs 8 rflags 10202 cr2  ffff8001806f=
 a000 cpl 4 rsp ffff80008723b328
 kernel: page fault trap, code=3D0
 Stopped in pid 0.95 (system) at netbsd:cpu_in_cksum+0xa5:       movl    0(%=
 rbx),%ecx
 db{4}> bt
 cpu_in_cksum() at netbsd:cpu_in_cksum+0xa5
 uvm_fault(0xffffffff80d8ca00, 0x8000, 1) -> e
 fatal page fault in supervisor mode
 trap type 6 code 0 rip ffffffff805736d4 cs 8 rflags 10246 cr2  8008 cpl 8 r=
 sp ffff80008723ace0
 kernel: page fault trap, code=3D0
 Faulted in DDB; continuing...
 db{4}>=20
 
 uvm_fault(0xffffffff80d5bd80, 0xffff8001806fa000, 1) -> e
 fatal page fault in supervisor mode
 trap type 6 code 0 rip ffffffff80571b65 cs 8 rflags 10202 cr2  ffff8001806f=
 a000 cpl 4 rsp ffff8000b5053328
 kernel: page fault trap, code=3D0
 Stopped in pid 0.96 (system) at netbsd:cpu_in_cksum+0xa5:       movl    0(%=
 rbx),%ecx
 db{7}> trace
 cpu_in_cksum() at netbsd:cpu_in_cksum+0xa5
 uvm_fault(0xffffffff80d8ca00, 0x8000, 1) -> e
 fatal page fault in supervisor mode
 trap type 6 code 0 rip ffffffff805736d4 cs 8 rflags 10246 cr2  8008 cpl 8 r=
 sp ffff8000b5052ce0
 kernel: page fault trap, code=3D0
 Faulted in DDB; continuing...
 db{7}>=20
 
 --=20
 						Greg A. Woods
 						Planix, Inc.
 
 <woods%planix.com@localhost>       +1 250 762-7675        http://www.planix.com/