kernel BUG at mm/prio_tree.c:78

kernel BUG at mm/prio_tree.c:78

[Paweł Słowik]

I had an oops on my home desktop, which is:
Linux desk 2.6.14 #1 PREEMPT Sat Oct 29 16:05:58 CEST 2005 i686
AMD Athlon(tm) XP 2000+ AuthenticAMD GNU/Linux
Syslog excerpt:

Nov  8 21:05:01 desk ------------[ cut here ]------------
Nov  8 21:05:01 desk kernel BUG at mm/prio_tree.c:78!
Nov  8 21:05:01 desk invalid operand: 0000 [#1]
Nov  8 21:05:01 desk PREEMPT 
Nov  8 21:05:01 desk Modules linked in: it87 hwmon_vid lm90 hwmon i2c_isa i2c_viapro i2c_core snd_seq_midi snd_emu10k1_synth snd_emux_synth snd_seq_virmidi snd_seq_midi_emul snd_emu10k1 snd_util_mem snd_hwdep snd_via82xx snd_ac97_codec snd_ac97_bus snd_mpu401_uart snd_rawmidi uhci_hcd cryptoloop loop radeon drm via_agp agpgart
Nov  8 21:05:01 desk CPU:    0
Nov  8 21:05:01 desk EIP:    0060:[<c014192b>]    Not tainted VLI
Nov  8 21:05:01 desk EFLAGS: 00010212   (2.6.14) 
Nov  8 21:05:01 desk EIP is at vma_prio_tree_add+0xab/0xc0
Nov  8 21:05:01 desk eax: dfd98964   ebx: c0805124   ecx: 0000010f   edx: 00000110
Nov  8 21:05:01 desk esi: dfd98964   edi: 00000000   ebp: dfd93474   esp: dd8ffe9c
Nov  8 21:05:01 desk ds: 007b   es: 007b   ss: 0068
Nov  8 21:05:01 desk Process grep (pid: 31686, threadinfo=dd8fe000 task=c0d810b0)
Nov  8 21:05:01 desk Stack: c4c3e284 db352334 c01460c0 c0805124 dfd98964 c4c3b964 dfd93460 00000000 
Nov  8 21:05:01 desk 00000000 00000000 c2e4bae0 dfd93460 da3d9700 c0805124 00000000 00000001 
Nov  8 21:05:01 desk db352334 c0147763 db352334 b7ee3000 b7ee5000 00000114 c0805124 b7ee3000 
Nov  8 21:05:01 desk Call Trace:
Nov  8 21:05:01 desk [<c01460c0>] vma_adjust+0x100/0x390
Nov  8 21:05:01 desk [<c0147763>] split_vma+0xa3/0xf0
Nov  8 21:05:01 desk [<c01478ec>] do_munmap+0x13c/0x150
Nov  8 21:05:01 desk [<c0146967>] do_mmap_pgoff+0x267/0x760
Nov  8 21:05:01 desk [<c0108588>] sys_mmap2+0x78/0xb0
Nov  8 21:05:01 desk [<c0102e81>] syscall_call+0x7/0xb
Nov  8 21:05:01 desk Code: 8b 4a 04 89 53 28 89 42 04 89 01 89 48 04 eb d8 8d 43 28 89 73 34 89 43 28 89 43 2c 89 5e 34 eb c7 0f 0b 4f 00 61 b7 33 c0 eb 93 <0f> 0b 4e 00 61 b7 33 c0 e9 68 ff ff ff 90 8d b4 26 00 00 00 00 
Nov  8 21:05:01 desk <6>note: grep[31686] exited with preempt_count 1
Nov  8 21:05:01 desk scheduling while atomic: grep/0x00000001/31686
Nov  8 21:05:01 desk [<c0327f92>] schedule+0x612/0x620
Nov  8 21:05:01 desk [<c0115885>] vprintk+0x1c5/0x290
Nov  8 21:05:01 desk [<c0328c8d>] rwsem_down_read_failed+0x8d/0x170
Nov  8 21:05:01 desk [<c0118bb2>] .text.lock.exit+0x27/0xb5
Nov  8 21:05:01 desk [<c0103ac0>] do_invalid_op+0x0/0xd0
Nov  8 21:05:01 desk [<c011782b>] do_exit+0xdb/0x440
Nov  8 21:05:01 desk [<c0103ac0>] do_invalid_op+0x0/0xd0
Nov  8 21:05:01 desk [<c010380d>] die+0x17d/0x180
Nov  8 21:05:01 desk [<c0103b6e>] do_invalid_op+0xae/0xd0
Nov  8 21:05:01 desk [<c016bc48>] update_atime+0x58/0xb0
Nov  8 21:05:01 desk [<c014192b>] vma_prio_tree_add+0xab/0xc0
Nov  8 21:05:01 desk [<c01352d3>] do_generic_mapping_read+0x313/0x5d0
Nov  8 21:05:01 desk [<c0162440>] page_put_link+0x0/0x40
Nov  8 21:05:01 desk [<c01fa68e>] rb_insert_color+0x8e/0xf0
Nov  8 21:05:01 desk [<c01f96d0>] prio_tree_insert+0xb0/0x1c0
Nov  8 21:05:01 desk [<c01030ab>] error_code+0x4f/0x54
Nov  8 21:05:01 desk [<c014192b>] vma_prio_tree_add+0xab/0xc0
Nov  8 21:05:01 desk [<c01460c0>] vma_adjust+0x100/0x390
Nov  8 21:05:01 desk [<c0147763>] split_vma+0xa3/0xf0
Nov  8 21:05:01 desk [<c01478ec>] do_munmap+0x13c/0x150
Nov  8 21:05:01 desk [<c0146967>] do_mmap_pgoff+0x267/0x760
Nov  8 21:05:01 desk [<c0108588>] sys_mmap2+0x78/0xb0
Nov  8 21:05:01 desk [<c0102e81>] syscall_call+0x7/0xb

The box is still up and running, but hangs when trying to read from
files:
/proc/31686/cmdline
/proc/31686/environ
/proc/31686/exe
/proc/31686/maps
/proc/31686/smaps
Process 31686 is "unkillable" (shows up as "D (disk sleep)").
So far, this happened only once and I dont't know, what might
be the cause. PID 31686 is a grep command, launched from the
"emerge" python script (emerge is Gentoo Linux package management
utility).

Is this an actual bug, or maybe hardware error? I would be grateful
for any help / comments on this.
I am not subscribed to the list, please CC.
Thank you.

-- 
Paweł Słowik
wik@iq.pl

Re: kernel BUG at mm/prio_tree.c:78

[Hugh Dickins]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 5647 bytes --]

On Tue, 8 Nov 2005, Paweł Słowik wrote:
> 
> I had an oops on my home desktop, which is:
> Linux desk 2.6.14 #1 PREEMPT Sat Oct 29 16:05:58 CEST 2005 i686
> AMD Athlon(tm) XP 2000+ AuthenticAMD GNU/Linux

Thanks for the report: interesting; uncertain comments at the end.

> Syslog excerpt:
> 
> Nov  8 21:05:01 desk ------------[ cut here ]------------
> Nov  8 21:05:01 desk kernel BUG at mm/prio_tree.c:78!
> Nov  8 21:05:01 desk invalid operand: 0000 [#1]
> Nov  8 21:05:01 desk PREEMPT 
> Nov  8 21:05:01 desk Modules linked in: it87 hwmon_vid lm90 hwmon i2c_isa i2c_viapro i2c_core snd_seq_midi snd_emu10k1_synth snd_emux_synth snd_seq_virmidi snd_seq_midi_emul snd_emu10k1 snd_util_mem snd_hwdep snd_via82xx snd_ac97_codec snd_ac97_bus snd_mpu401_uart snd_rawmidi uhci_hcd cryptoloop loop radeon drm via_agp agpgart
> Nov  8 21:05:01 desk CPU:    0
> Nov  8 21:05:01 desk EIP:    0060:[<c014192b>]    Not tainted VLI
> Nov  8 21:05:01 desk EFLAGS: 00010212   (2.6.14) 
> Nov  8 21:05:01 desk EIP is at vma_prio_tree_add+0xab/0xc0
> Nov  8 21:05:01 desk eax: dfd98964   ebx: c0805124   ecx: 0000010f   edx: 00000110
> Nov  8 21:05:01 desk esi: dfd98964   edi: 00000000   ebp: dfd93474   esp: dd8ffe9c
> Nov  8 21:05:01 desk ds: 007b   es: 007b   ss: 0068
> Nov  8 21:05:01 desk Process grep (pid: 31686, threadinfo=dd8fe000 task=c0d810b0)
> Nov  8 21:05:01 desk Stack: c4c3e284 db352334 c01460c0 c0805124 dfd98964 c4c3b964 dfd93460 00000000 
> Nov  8 21:05:01 desk 00000000 00000000 c2e4bae0 dfd93460 da3d9700 c0805124 00000000 00000001 
> Nov  8 21:05:01 desk db352334 c0147763 db352334 b7ee3000 b7ee5000 00000114 c0805124 b7ee3000 
> Nov  8 21:05:01 desk Call Trace:
> Nov  8 21:05:01 desk [<c01460c0>] vma_adjust+0x100/0x390
> Nov  8 21:05:01 desk [<c0147763>] split_vma+0xa3/0xf0
> Nov  8 21:05:01 desk [<c01478ec>] do_munmap+0x13c/0x150
> Nov  8 21:05:01 desk [<c0146967>] do_mmap_pgoff+0x267/0x760
> Nov  8 21:05:01 desk [<c0108588>] sys_mmap2+0x78/0xb0
> Nov  8 21:05:01 desk [<c0102e81>] syscall_call+0x7/0xb
> Nov  8 21:05:01 desk Code: 8b 4a 04 89 53 28 89 42 04 89 01 89 48 04 eb d8 8d 43 28 89 73 34 89 43 28 89 43 2c 89 5e 34 eb c7 0f 0b 4f 00 61 b7 33 c0 eb 93 <0f> 0b 4e 00 61 b7 33 c0 e9 68 ff ff ff 90 8d b4 26 00 00 00 00 
> Nov  8 21:05:01 desk <6>note: grep[31686] exited with preempt_count 1
> Nov  8 21:05:01 desk scheduling while atomic: grep/0x00000001/31686
> Nov  8 21:05:01 desk [<c0327f92>] schedule+0x612/0x620
> Nov  8 21:05:01 desk [<c0115885>] vprintk+0x1c5/0x290
> Nov  8 21:05:01 desk [<c0328c8d>] rwsem_down_read_failed+0x8d/0x170
> Nov  8 21:05:01 desk [<c0118bb2>] .text.lock.exit+0x27/0xb5
> Nov  8 21:05:01 desk [<c0103ac0>] do_invalid_op+0x0/0xd0
> Nov  8 21:05:01 desk [<c011782b>] do_exit+0xdb/0x440
> Nov  8 21:05:01 desk [<c0103ac0>] do_invalid_op+0x0/0xd0
> Nov  8 21:05:01 desk [<c010380d>] die+0x17d/0x180
> Nov  8 21:05:01 desk [<c0103b6e>] do_invalid_op+0xae/0xd0
> Nov  8 21:05:01 desk [<c016bc48>] update_atime+0x58/0xb0
> Nov  8 21:05:01 desk [<c014192b>] vma_prio_tree_add+0xab/0xc0
> Nov  8 21:05:01 desk [<c01352d3>] do_generic_mapping_read+0x313/0x5d0
> Nov  8 21:05:01 desk [<c0162440>] page_put_link+0x0/0x40
> Nov  8 21:05:01 desk [<c01fa68e>] rb_insert_color+0x8e/0xf0
> Nov  8 21:05:01 desk [<c01f96d0>] prio_tree_insert+0xb0/0x1c0
> Nov  8 21:05:01 desk [<c01030ab>] error_code+0x4f/0x54
> Nov  8 21:05:01 desk [<c014192b>] vma_prio_tree_add+0xab/0xc0
> Nov  8 21:05:01 desk [<c01460c0>] vma_adjust+0x100/0x390
> Nov  8 21:05:01 desk [<c0147763>] split_vma+0xa3/0xf0
> Nov  8 21:05:01 desk [<c01478ec>] do_munmap+0x13c/0x150
> Nov  8 21:05:01 desk [<c0146967>] do_mmap_pgoff+0x267/0x760
> Nov  8 21:05:01 desk [<c0108588>] sys_mmap2+0x78/0xb0
> Nov  8 21:05:01 desk [<c0102e81>] syscall_call+0x7/0xb
> 
> The box is still up and running, but hangs when trying to read from
> files:
> /proc/31686/cmdline
> /proc/31686/environ
> /proc/31686/exe
> /proc/31686/maps
> /proc/31686/smaps
> Process 31686 is "unkillable" (shows up as "D (disk sleep)").

Those hangs and unkillability are just the consequence of the BUG
happening in an awkward place, I think.  Though that would be more
on an SMP system, which yours is not.  The stack backtrace naturally
contains stale addresses from before, it's hard to work out whether
there's actually something further wrong after the BUG_ON or not.

> So far, this happened only once and I dont't know, what might
> be the cause. PID 31686 is a grep command, launched from the
> "emerge" python script (emerge is Gentoo Linux package management
> utility).
> 
> Is this an actual bug, or maybe hardware error?

I'm not sure.  There _used_ to be a bug which caused this, but Rajesh
fixed that in 2.6.10, and the fix looks like it's still there in 2.6.14.
And it needed something a lot more complex than "grep" to trigger it.

My guess at this point is that it's a hardware problem i.e. bad memory,
cpu overheating, that kind of thing.  (The BUG_ON is surprised to find
vm_pgoffs in ecx: 0000010f edx: 00000110 different: not a single-bit
error, but perhaps it could arise from a single-bit error nearby.)

Please give memtest86 an overnight run (though finding nothing won't
prove your memory okay), and be on the lookout for other strange
behaviour on this machine.  If the next strange thing that happens is
another BUG at mm/prio_tree.c:78! that will suggest a kernel bug here.

Hugh

> I would be grateful for any help / comments on this.
> I am not subscribed to the list, please CC.
> Thank you.
> 
> -- 
> Paweł Słowik
> wik@iq.pl