Re: [Crash-utility] x86 remap allocator in kernel 3.0
----- Original Message -----
On 01/11/2012 06:53 AM, Petr Tesarik wrote:
> Dne Út 10. ledna 2012 19:23:24 Petr Tesarik napsal(a):
>> Dne Út 10. ledna 2012 19:14:32 Petr Tesarik napsal(a):
... [ cut ] ...
>> crash> vtop f2800080
>> VIRTUAL PHYSICAL
>> f2800080 1fde00080
>>
>> PAGE DIRECTORY: c08ed000
>> PGD: c08ed018 => 8ea001
>> PMD: 8eaca0 => 80000001fde001e3
>> PAGE: 1fde00000 (2MB)
>>
>> PTE PHYSICAL FLAGS
>> 80000001fde001e3 1fde00000
>> (PRESENT|RW|ACCESSED|DIRTY|PSE|GLOBAL|NX)
>>
>> PAGE PHYSICAL MAPPING INDEX CNT FLAGS
>
> BTW the data from struct page is really missing here. I traced this down to an
> integer overflow in dump_memory_nodes():
... [ cut ] ...
> David (Mair), could you address this, as already discussed in private mails,
> please?
The attached patch fixes this for me.
Hmmm, not so much for me...
When I test the patch on RHEL5, RHEL6 and Fedora x86 kernels, the
command always fails like this:
crash> kmem -n
NODE SIZE PGLIST_DATA BOOTMEM_DATA NODE_ZONES
0 262075 c0a3a680 c0aa5ce8 c0a3a680
c0a3b1c0
c0a3bd00
c0a3c840
MEM_MAP START_PADDR START_MAPNR
Segmentation fault
$
I haven't look into it, and this is probably not related:
cc -c -g -DX86 -m32 -D_FILE_OFFSET_BITS=64 -DGDB_7_3_1 memory.c -Wall -O2
-Wstrict-prototypes -Wmissing-prototypes -fstack-protector
memory.c: In function 'dump_memory_nodes':
memory.c:13410: warning: cast to pointer from integer of different size
memory.c:13199: warning: 'node_start_paddr' may be used uninitialized in this
function
But from under gdb:
crash> kmem -n
[Detaching after fork from child process 16870.]
Program received signal SIGSEGV, Segmentation fault.
0x0809cd94 in mkstring (s=0xffe8a8bc " c0a3a680 ", size=16, flags=133,
opt=0x1000 <Address 0x1000 out of bounds>)
at tools.c:1620
1620 sprintf(s, "%llx", *((ulonglong *)opt));
(gdb) bt
#0 0x0809cd94 in mkstring (s=0xffe8a8bc " c0a3a680 ", size=16, flags=133,
opt=0x1000 <Address 0x1000 out of bounds>)
at tools.c:1620
#1 0x080b1ad7 in dump_memory_nodes (initialize=0) at memory.c:13406
#2 0x080d46cc in cmd_kmem () at memory.c:4221
#3 0x080941b8 in exec_command () at main.c:751
#4 0x08093fe6 in main_loop () at main.c:699
#5 0x081db622 in current_interp_command_loop ()
#6 0x081dbf01 in captured_command_loop ()
#7 0x081db0a4 in catch_errors ()
#8 0x081dce07 in captured_main ()
#9 0x081db0a4 in catch_errors ()
#10 0x081dce49 in gdb_main ()
#11 0x081dce99 in gdb_main_entry ()
#12 0x08116668 in gdb_main_loop (argc=2, argv=0xffe8d494) at gdb_interface.c:75
#13 0x08093ce0 in main (argc=3, argv=0xffe8d494) at main.c:603
(gdb) p opt
$1 = 0x1000 <Address 0x1000 out of bounds>
(gdb)
I thought it might be just an x86 issue, but it also fails
the same way on RHEL5, RHEL6 and Fedora x86_64 kernels.
Dave