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>
Subject: Re: kern/41974: panic in cpu_in_cksum / likely NFS issue
Date: Wed, 25 Feb 2015 16:41:01 -0800

 At Tue, 24 Feb 2015 20:38:10 +0100, Joerg Sonnenberger <joerg%britannica.be@localhost=
 c.de> wrote:
 Subject: Re: kern/41974: panic in cpu_in_cksum / likely NFS issue
 >=20
 > Can you disable the CPU_IN_CKSUM option and trigger to trigger it again?
 > The C version would be easier to instrument to see why the mbuf chain is
 > bad...
 
 Well, it seemed quite a lot more difficult to trigger the crash with the
 C version, but eventually, just when I didn't think it would happen....
 
 The back-trace looks better, and the machine didn't hang quite so badly,
 but syncing still caused a second panic, and so there was no crash dump
 either.
 
 fatal page fault in supervisor mode
 trap type 6 code 0 rip ffffffff8054021e cs 8 rflags 10206 cr2  ffff8001806f=
 a000 cpl 4 rsp ffff800086b58870
 kernel: page fault trap, code=3D0
 Stopped in pid 0.5 (system) at  netbsd:cpu_in_cksum+0xce:       movl    0xf=
 fffffffffffffc0(%rsi),%edx
 db{0}> bt
 cpu_in_cksum() at netbsd:cpu_in_cksum+0xce
 in_delayed_cksum() at netbsd:in_delayed_cksum+0x3c
 ip_output() at netbsd:ip_output+0xd68
 udp_output() at netbsd:udp_output+0x221
 udp_usrreq() at netbsd:udp_usrreq+0x31c
 udp_usrreq_wrapper() at netbsd:udp_usrreq_wrapper+0x51
 nfs_timer() at netbsd:nfs_timer+0x41f
 callout_softclock() at netbsd:callout_softclock+0x21b
 softint_dispatch() at netbsd:softint_dispatch+0xc3
 DDB lost frame for netbsd:Xsoftintr+0x50, trying 0xffff800086b58d70
 Xsoftintr() at netbsd:Xsoftintr+0x50
 --- interrupt ---
 0:
 db{0}> sh reg
 ds          0
 es          0
 fs          0
 gs          0
 rdi         0
 rsi         0xffff8001806fa040
 rbp         0xffff800086b58890
 rbx         0
 rdx         0
 rcx         0
 rax         0x8000
 r8          0x7fc0
 r9          0xc000000000000000
 r10         0x43ab4701
 r11         0x8000
 r12         0xffff80003ec23400
 r13         0x8000
 r14         0
 r15         0
 rip         0xffffffff8054021e  cpu_in_cksum+0xce
 cs          0x8
 rflags      0x10206
 rsp         0xffff800086b58870
 ss          0
 netbsd:cpu_in_cksum+0xce:       movl    0xffffffffffffffc0(%rsi),%edx
 db{0}> sh uvmexp
 Current UVM status:
   pagesize=3D4096 (0x1000), pagemask=3D0xfff, pageshift=3D12
   8129044 VM pages: 692704 active, 111 inactive, 2027 wired, 7047912 free
   pages  127267 anon, 562283 file, 5292 exec
   freemin=3D2048, free-target=3D2730, wired-max=3D2709681
   faults=3D8436894, traps=3D8435463, intrs=3D69970442, ctxswitch=3D249513713
   softint=3D96511309, syscalls=3D171036039, swapins=3D14, swapouts=3D23
   fault counts:
     noram=3D0, noanon=3D0, pgwait=3D0, pgrele=3D0
     ok relocks(total)=3D4570(4571), anget(retrys)=3D107575(0), amapcopy=3D2=
 42698
     neighbor anon/obj pg=3D148737/251970, gets(lock/unlock)=3D61640/4571
     cases: anon=3D71314, anoncow=3D36270, obj=3D58530, prcopy=3D3110, przer=
 o=3D3520508
   daemon and swap counts:
     woke=3D521, revs=3D521, scans=3D4741657, obscans=3D4627347, anscans=3D0
     busy=3D0, freed=3D4627347, reactivate=3D243, deactivate=3D7295399
     pageouts=3D0, pending=3D0, nswget=3D0
     nswapdev=3D1, swpgavail=3D12582911
     swpages=3D12582911, swpginuse=3D0, swpgonly=3D0, paging=3D0
 db{0}> reboot
 syncing disks... panic: assert_sleepable: softint caller=3D0xffffffff804f82=
 69
 fatal breakpoint trap in supervisor mode
 trap type 1 code 0 rip ffffffff80571f55 cs 8 rflags 246 cr2  ffff8001806fa0=
 00 cpl 0 rsp ffff800086b58140
 Stopped in pid 0.5 (system) at  netbsd:breakpoint+0x5:  leave
 db{0}> bt
 breakpoint() at netbsd:breakpoint+0x5
 panic() at netbsd:panic+0x24d
 assert_sleepable() at netbsd:assert_sleepable+0x80
 _fstrans_start() at netbsd:_fstrans_start+0x29
 ffs_sync() at netbsd:ffs_sync+0x6f
 VFS_SYNC() at netbsd:VFS_SYNC+0x33
 sys_sync() at netbsd:sys_sync+0xeb
 vfs_shutdown() at netbsd:vfs_shutdown+0x50
 cpu_reboot() at netbsd:cpu_reboot+0x100
 db_reboot_cmd() at netbsd:db_reboot_cmd+0x47
 db_command() at netbsd:db_command+0xb0
 db_command_loop() at netbsd:db_command_loop+0xf8
 db_trap() at netbsd:db_trap+0x114
 kdb_trap() at netbsd:kdb_trap+0xf3
 trap() at netbsd:trap+0x34a
 fatal page fault in supervisor mode
 trap type 6 code 0 rip ffffffff80573e7b cs 8 rflags 10247 cr2  b8 cpl 8 rsp=
  ffff800086b57b40
 kernel: page fault trap, code=3D0
 Faulted in DDB; continuing...
 db{0}> sh reg
 ds          0x8150
 es          0
 fs          0x8100
 gs          0x7
 rdi         0
 rsi         0x3f8
 rbp         0xffff800086b58140
 rbx         0xffff800086b58150
 rdx         0x8
 rcx         0
 rax         0x1
 r8          0xffffffff80aa619a  copyright+0xb381a
 r9          0x1
 r10         0xffff800086b58060
 r11         0xffffffff802ea7f0  comcnputc
 r12         0x104
 r13         0xffffffff80a41eb0  copyright+0x4f530
 r14         0x1
 r15         0xffff80003ec49900
 rip         0xffffffff80571f55  breakpoint+0x5
 cs          0x8
 rflags      0x246
 rsp         0xffff800086b58140
 ss          0
 netbsd:breakpoint+0x5:  leave
 db{0}> reboot
 rebooting...
 
 --=20
 						Greg A. Woods
 						Planix, Inc.
 
 <woods%planix.com@localhost>       +1 250 762-7675        http://www.planix.com/