Re: anticipatory scheduler merged

[James H. Cloos Jr.]

>>>>> "Andrew" == Andrew Morton <[e-mail]> writes:

Andrew> - These changes have been well tested, but it is five months
Andrew> work and over 100 patches.  There's probably a bug or two.  If
Andrew> you suspect that something has gone wrong at the block layer
Andrew> (lots of tasks stuck in D state) then please retest with
Andrew> `elevator=deadline'.

Looks like I got hit by such a bug.¹  It left a strip(1) in __down,
and a subsequent rm(1) recursing to that file also is in __down.

I’ll give a try after sleep w/ deadline....

The dumps I still have² are:

Unable to handle kernel NULL pointer dereference at virtual address 00000000
 printing eip:
00000000
*pde = 00000000
Oops: 0000 [#2]
CPU:    0
EIP:    0060:[<00000000>]    Not tainted
EFLAGS: 00010286
EIP is at 0x0
eax: c04b0d20   ebx: fffffff4   ecx: d87bcd3c   edx: d87bcd3c
esi: ca6466c4   edi: d0f55e00   ebp: c9b51f70   esp: c9b51f08
ds: 007b   es: 007b   ss: 0068
Process strip (pid: 18461, threadinfo=c9b50000 task=c40a32a0)
Stack: c01675f6 ca6466c4 d0f55e00 c9b51f70 ffffffd8 d87bcd20 00000242 c9b51f70 
       c0167f24 c9b51f78 d87bcd20 c9b51f70 c9b50000 c9b51f78 00000001 00000002 
       cad39d60 00000241 00000002 c520e000 c9b50000 c015734b c520e000 00000242 
Call Trace:
 [<c01675f6>] __lookup_hash+0xc6/0xe0
 [<c0167f24>] open_namei+0x334/0x460
 [<c015734b>] filp_open+0x3b/0x70
 [<c015786b>] sys_open+0x5b/0xa0
 [<c010b379>] sysenter_past_esp+0x52/0x71

Code:  Bad EIP value.

ksymoops adds this bit:

>>EIP; 00000000 Before first symbol

>>eax; c04b0d20 <ext3_file_inode_operations+0/60>
>>ebx; fffffff4 <TSS_ESP0_OFFSET+1f0/????>
>>ecx; d87bcd3c <_end+181db9b8/3fa1cc7c>
>>edx; d87bcd3c <_end+181db9b8/3fa1cc7c>
>>esi; ca6466c4 <_end+a065340/3fa1cc7c>
>>edi; d0f55e00 <_end+10974a7c/3fa1cc7c>
>>ebp; c9b51f70 <_end+9570bec/3fa1cc7c>
>>esp; c9b51f08 <_end+9570b84/3fa1cc7c>

and the next oops is:

Unable to handle kernel NULL pointer dereference at virtual address 00000000
 printing eip:
c0142ef0
*pde = 00000000
Oops: 0000 [#3]
CPU:    0
EIP:    0060:[<c0142ef0>]    Not tainted
EFLAGS: 00010006
EIP is at kfree+0x30/0x70
eax: 00140000   ebx: ce0afaa0   ecx: dd7127b0   edx: 00000000
esi: 00000100   edi: 00000206   ebp: dd7127b0   esp: cad1bf48
ds: 007b   es: 007b   ss: 0068
Process lsof (pid: 18589, threadinfo=cad1a000 task=c40a26a0)
Stack: 00000000 ce0afab8 ce0afaa0 c8df17a0 dd7127b0 c0178635 00000100 00000000 
       c8df17a0 c0178610 dffd61e0 c015951a dd7127b0 c8df17a0 d1389d40 c8df17a0 
       d3e403e0 00000000 cad1a000 c015792d c8df17a0 d3e403e0 d3e403e0 c8df17a0 
Call Trace:
 [<c0178635>] seq_release_private+0x25/0x48
 [<c0178610>] seq_release_private+0x0/0x48
 [<c015951a>] __fput+0x12a/0x170
 [<c015792d>] filp_close+0x4d/0x90
 [<c01579cb>] sys_close+0x5b/0x90
 [<c010b379>] sysenter_past_esp+0x52/0x71

Code: 8b 1a 8b 03 3b 43 04 73 18 89 74 83 10 ff 03 57 9d 8b 5c 24 

ksymoops adds:

>>EIP; c0142ef0 <kfree+30/70>   <=====

>>ebx; ce0afaa0 <_end+dace71c/3fa1cc7c>
>>ecx; dd7127b0 <_end+1d13142c/3fa1cc7c>
>>ebp; dd7127b0 <_end+1d13142c/3fa1cc7c>
>>esp; cad1bf48 <_end+a73abc4/3fa1cc7c>

Trace; c0178635 <seq_release_private+25/48>
Trace; c0178610 <seq_release_private+0/48>
Trace; c015951a <__fput+12a/170>
Trace; c015792d <filp_close+4d/90>
Trace; c01579cb <sys_close+5b/90>
Trace; c010b379 <sysenter_past_esp+52/71>

Code;  c0142ef0 <kfree+30/70>
00000000 <_EIP>:
Code;  c0142ef0 <kfree+30/70>   <=====
   0:   8b 1a                     mov    (%edx),%ebx   <=====
Code;  c0142ef2 <kfree+32/70>
   2:   8b 03                     mov    (%ebx),%eax
Code;  c0142ef4 <kfree+34/70>
   4:   3b 43 04                  cmp    0x4(%ebx),%eax
Code;  c0142ef7 <kfree+37/70>
   7:   73 18                     jae    21 <_EIP+0x21>
Code;  c0142ef9 <kfree+39/70>
   9:   89 74 83 10               mov    %esi,0x10(%ebx,%eax,4)
Code;  c0142efd <kfree+3d/70>
   d:   ff 03                     incl   (%ebx)
Code;  c0142eff <kfree+3f/70>
   f:   57                        push   %edi
Code;  c0142f00 <kfree+40/70>
  10:   9d                        popf   
Code;  c0142f01 <kfree+41/70>
  11:   8b 5c 24 00               mov    0x0(%esp,1),%ebx

I presume there was another Oops: 0000, but it is lost².

-JimC

¹ And I didn’t even know I was running the new scheduler; the
  bk-commits-head email lagged enough behind the push to
  linux.bkbits.net that I received it after booting
  the new kernel....  I guess that answers the
  question of which comes first. ;-/

² Turns out msyslogd(8)’s im_linux(8)’ is not too
  happy w/ 2.5’s lack of /proc/ksyms.  [SIGH]