2.6.20 kernel hang with USB drive and vfat doing ftruncate

2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Kumar Gala]

I'm seeing an issue with a stock 2.6.20 kernel running on an embedded  
PPC.  I've got a usb flash drive plugged in and the filesystem on the  
drive is vfat.  Running with 64M and no swap.

If I execute a series of large (100M+) ftruncate() on the disk the  
kernel will hang and never return.  It seems to be stuck in the idle  
loop().

The following is the test program I'm running:

#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>

void usage (void)
{
         printf ("truncate_test <filename> <size>\n\n");
}

int main(int argc, char *argv[])
{
         int fd, i;
         int ret = 0;
         unsigned int len;

         if (argc != 3) {
                 printf("Invalid number of arguments\n\n");
                 usage();
                 exit(1);
         }

         fd = open(argv[1], O_CREAT|O_RDWR|O_TRUNC, S_IRWXU);
         len = strtoul(argv[2], NULL, 0);

         ret = ftruncate(fd, len);

         if (ret)
                 printf ("ftruncate ret = %d %d\n", ret, errno);

         close(fd);

         return ret;
}

I usually run the following twice to get the hang state:

time ./trunc_test bar 100000000 &
time ./trunc_test baz 100000000 &

I was wondering if anyone had any suggestions on what to poke at next  
to try and figure out what is going on.

- k

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[OGAWA Hirofumi]

Kumar Gala <galak@kernel.crashing.org> writes:

> I'm seeing an issue with a stock 2.6.20 kernel running on an embedded  
> PPC.  I've got a usb flash drive plugged in and the filesystem on the  
> drive is vfat.  Running with 64M and no swap.
>
> If I execute a series of large (100M+) ftruncate() on the disk the  
> kernel will hang and never return.  It seems to be stuck in the idle  
> loop().
>
> The following is the test program I'm running:
>
> #include <sys/mman.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <fcntl.h>
> #include <stdio.h>
> #include <unistd.h>
> #include <errno.h>
>
> void usage (void)
> {
>          printf ("truncate_test <filename> <size>\n\n");
> }
>
> int main(int argc, char *argv[])
> {
>          int fd, i;
>          int ret = 0;
>          unsigned int len;
>
>          if (argc != 3) {
>                  printf("Invalid number of arguments\n\n");
>                  usage();
>                  exit(1);
>          }
>
>          fd = open(argv[1], O_CREAT|O_RDWR|O_TRUNC, S_IRWXU);
>          len = strtoul(argv[2], NULL, 0);
>
>          ret = ftruncate(fd, len);
>
>          if (ret)
>                  printf ("ftruncate ret = %d %d\n", ret, errno);
>
>          close(fd);
>
>          return ret;
> }
>
> I usually run the following twice to get the hang state:
>
> time ./trunc_test bar 100000000 &
> time ./trunc_test baz 100000000 &
>
> I was wondering if anyone had any suggestions on what to poke at next  
> to try and figure out what is going on.

Can you check /sys/block/xxx/stat or something to make sure there is
no outstanding IO request?

It seems to be no response from the lower layer...
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Kumar Gala]

On Feb 18, 2007, at 10:10 AM, OGAWA Hirofumi wrote:

> Kumar Gala <galak@kernel.crashing.org> writes:
>
>> I'm seeing an issue with a stock 2.6.20 kernel running on an embedded
>> PPC.  I've got a usb flash drive plugged in and the filesystem on the
>> drive is vfat.  Running with 64M and no swap.
>>
>> If I execute a series of large (100M+) ftruncate() on the disk the
>> kernel will hang and never return.  It seems to be stuck in the idle
>> loop().
>>
>> The following is the test program I'm running:
>>
>> #include <sys/mman.h>
>> #include <sys/types.h>
>> #include <sys/stat.h>
>> #include <fcntl.h>
>> #include <stdio.h>
>> #include <unistd.h>
>> #include <errno.h>
>>
>> void usage (void)
>> {
>>          printf ("truncate_test <filename> <size>\n\n");
>> }
>>
>> int main(int argc, char *argv[])
>> {
>>          int fd, i;
>>          int ret = 0;
>>          unsigned int len;
>>
>>          if (argc != 3) {
>>                  printf("Invalid number of arguments\n\n");
>>                  usage();
>>                  exit(1);
>>          }
>>
>>          fd = open(argv[1], O_CREAT|O_RDWR|O_TRUNC, S_IRWXU);
>>          len = strtoul(argv[2], NULL, 0);
>>
>>          ret = ftruncate(fd, len);
>>
>>          if (ret)
>>                  printf ("ftruncate ret = %d %d\n", ret, errno);
>>
>>          close(fd);
>>
>>          return ret;
>> }
>>
>> I usually run the following twice to get the hang state:
>>
>> time ./trunc_test bar 100000000 &
>> time ./trunc_test baz 100000000 &
>>
>> I was wondering if anyone had any suggestions on what to poke at next
>> to try and figure out what is going on.
>
> Can you check /sys/block/xxx/stat or something to make sure there is
> no outstanding IO request?
>
> It seems to be no response from the lower layer...

Once the system locks up I dont have any ability to do anything.

- k

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Kumar Gala]

On Feb 18, 2007, at 10:10 AM, OGAWA Hirofumi wrote:

> Kumar Gala <galak@kernel.crashing.org> writes:
>
>> I'm seeing an issue with a stock 2.6.20 kernel running on an embedded
>> PPC.  I've got a usb flash drive plugged in and the filesystem on the
>> drive is vfat.  Running with 64M and no swap.
>>
>> If I execute a series of large (100M+) ftruncate() on the disk the
>> kernel will hang and never return.  It seems to be stuck in the idle
>> loop().
>>
>> The following is the test program I'm running:
>>
>> #include <sys/mman.h>
>> #include <sys/types.h>
>> #include <sys/stat.h>
>> #include <fcntl.h>
>> #include <stdio.h>
>> #include <unistd.h>
>> #include <errno.h>
>>
>> void usage (void)
>> {
>>          printf ("truncate_test <filename> <size>\n\n");
>> }
>>
>> int main(int argc, char *argv[])
>> {
>>          int fd, i;
>>          int ret = 0;
>>          unsigned int len;
>>
>>          if (argc != 3) {
>>                  printf("Invalid number of arguments\n\n");
>>                  usage();
>>                  exit(1);
>>          }
>>
>>          fd = open(argv[1], O_CREAT|O_RDWR|O_TRUNC, S_IRWXU);
>>          len = strtoul(argv[2], NULL, 0);
>>
>>          ret = ftruncate(fd, len);
>>
>>          if (ret)
>>                  printf ("ftruncate ret = %d %d\n", ret, errno);
>>
>>          close(fd);
>>
>>          return ret;
>> }
>>
>> I usually run the following twice to get the hang state:
>>
>> time ./trunc_test bar 100000000 &
>> time ./trunc_test baz 100000000 &
>>
>> I was wondering if anyone had any suggestions on what to poke at next
>> to try and figure out what is going on.

So I realized I could use sysrq to provide some more debug  
information.  When the system locks up I get the following output  
from 't'

[  496.901002] Show State
[  496.903356]
[  496.903360]                          free                         
sibling
[  496.911532]   task             PC    stack   pid father child  
younger older
[  496.918486] init          S 3009C7EC     0     1      0      
2               (NOTLB)
[  496.926169] Call Trace:
[  496.928611] [C3FC7DA0] [C006F03C] __link_path_walk+0xd24/0x112c  
(unreliable)
[  496.935687] [C3FC7E60] [C00083AC] __switch_to+0x28/0x40
[  496.940931] [C3FC7E80] [C01F4B78] schedule+0x324/0x6bc
[  496.946086] [C3FC7EC0] [C001E164] do_wait+0x700/0x100c
[  496.951242] [C3FC7F40] [C000FAD4] ret_from_syscall+0x0/0x38
[  496.956828] --- Exception: c01 at 0x3009c7ec
[  496.961099]     LR = 0x3009c3e0
[  496.964234] ksoftirqd/0   S 00000000     0     2       
1             3       (L-TLB)
[  496.971913] Call Trace:
[  496.974355] [C033DE80] [C0133F64] scsi_io_completion+0x74/0x318  
(unreliable)
[  496.981428] [C033DF40] [C00083AC] __switch_to+0x28/0x40
[  496.986664] [C033DF60] [C01F4B78] schedule+0x324/0x6bc
[  496.991811] [C033DFA0] [C00210CC] ksoftirqd+0xfc/0x114
[  496.996960] [C033DFC0] [C0033E48] kthread+0xf4/0x130
[  497.001941] [C033DFF0] [C001093C] kernel_thread+0x44/0x60
[  497.007350] events/0      S 00000000     0     3       
1             4     2 (L-TLB)
[  497.015030] Call Trace:
[  497.017472] [C033FEE0] [C00083AC] __switch_to+0x28/0x40
[  497.022707] [C033FF00] [C01F4B78] schedule+0x324/0x6bc
[  497.027855] [C033FF40] [C002F67C] worker_thread+0x144/0x148
[  497.033435] [C033FFC0] [C0033E48] kthread+0xf4/0x130
[  497.038409] [C033FFF0] [C001093C] kernel_thread+0x44/0x60
[  497.043817] khelper       S 00000000     0     4       
1             5     3 (L-TLB)
[  497.051497] Call Trace:
[  497.053940] [C3FE1E20] [C3FE0000] 0xc3fe0000 (unreliable)
[  497.059351] [C3FE1EE0] [C00083AC] __switch_to+0x28/0x40
[  497.064586] [C3FE1F00] [C01F4B78] schedule+0x324/0x6bc
[  497.069734] [C3FE1F40] [C002F67C] worker_thread+0x144/0x148
[  497.075316] [C3FE1FC0] [C0033E48] kthread+0xf4/0x130
[  497.080291] [C3FE1FF0] [C001093C] kernel_thread+0x44/0x60
[  497.085697] kthread       S 00000000     0     5      1    37      
617     4 (L-TLB)
[  497.093378] Call Trace:
[  497.095820] [C3FCBE20] [00001032] 0x1032 (unreliable)
[  497.100881] --- Exception: c3fcbef0 at __switch_to+0x28/0x40
[  497.106545]     LR = 0xc3fcbef0
[  497.109681] [C3FCBEE0] [C00083AC] __switch_to+0x28/0x40 (unreliable)
[  497.116051] [C3FCBF00] [C01F4B78] schedule+0x324/0x6bc
[  497.121201] [C3FCBF40] [C002F67C] worker_thread+0x144/0x148
[  497.126783] [C3FCBFC0] [C0033E48] kthread+0xf4/0x130
[  497.131758] [C3FCBFF0] [C001093C] kernel_thread+0x44/0x60
[  497.137165] kblockd/0     S 00000000     0    37      5             
41       (L-TLB)
[  497.144845] Call Trace:
[  497.147286] [C3D9FE20] [C3EBF490] 0xc3ebf490 (unreliable)
[  497.152697] [C3D9FEE0] [C00083AC] __switch_to+0x28/0x40
[  497.157933] [C3D9FF00] [C01F4B78] schedule+0x324/0x6bc
[  497.163082] [C3D9FF40] [C002F67C] worker_thread+0x144/0x148
[  497.168663] [C3D9FFC0] [C0033E48] kthread+0xf4/0x130
[  497.173637] [C3D9FFF0] [C001093C] kernel_thread+0x44/0x60
[  497.179045] khubd         S 00000000     0    41      5             
53    37 (L-TLB)
[  497.186726] Call Trace:
[  497.189167] [C0341E00] [C3F03900] 0xc3f03900 (unreliable)
[  497.194578] [C0341EC0] [C00083AC] __switch_to+0x28/0x40
[  497.199813] [C0341EE0] [C01F4B78] schedule+0x324/0x6bc
[  497.204961] [C0341F20] [C0152288] hub_thread+0xb40/0xcc0
[  497.210283] [C0341FC0] [C0033E48] kthread+0xf4/0x130
[  497.215257] [C0341FF0] [C001093C] kernel_thread+0x44/0x60
[  497.220664] pdflush       D 00000000     0    53      5             
55    41 (L-TLB)
[  497.228344] Call Trace:
[  497.230786] [C3CABD10] [C008E098] __find_get_block+0x10c/0x288  
(unreliable)
[  497.237769] [C3CABDD0] [C00083AC] __switch_to+0x28/0x40
[  497.243004] [C3CABDF0] [C01F4B78] schedule+0x324/0x6bc
[  497.248152] [C3CABE30] [C01F5D6C] schedule_timeout+0x6c/0xd0
[  497.253822] [C3CABE70] [C01F5C9C] io_schedule_timeout+0x30/0x54
[  497.259752] [C3CABE90] [C0050DE4] congestion_wait+0x64/0x8c
[  497.265343] [C3CABEE0] [C004AA9C] background_writeout+0x44/0xe8
[  497.271274] [C3CABF50] [C004BE04] pdflush+0x16c/0x27c
[  497.276335] [C3CABFC0] [C0033E48] kthread+0xf4/0x130
[  497.281311] [C3CABFF0] [C001093C] kernel_thread+0x44/0x60
[  497.286718] kswapd0       D 00000000     0    55      5             
56    53 (L-TLB)
[  497.294399] Call Trace:
[  497.296841] [C3DEFB70] [C0025FE8] run_timer_softirq+0x20/0x230  
(unreliable)
[  497.303823] [C3DEFC30] [C00083AC] __switch_to+0x28/0x40
[  497.309058] [C3DEFC50] [C01F4B78] schedule+0x324/0x6bc
[  497.314207] [C3DEFC90] [C01F5D6C] schedule_timeout+0x6c/0xd0
[  497.319876] --- Exception: c3defd60 at 0xc3deff40
[  497.324582]     LR = 0xc3dee000
[  497.327718] [C3DEFCD0] [C01F5C9C] io_schedule_timeout+0x30/0x54  
(unreliable)
[  497.334783] [C3DEFCF0] [C0050DE4] congestion_wait+0x64/0x8c
[  497.340367] [C3DEFD40] [C004A9F0] throttle_vm_writeout+0x1c/0x84
[  497.346384] [C3DEFD60] [C004F33C] shrink_zone+0xbb0/0xfe4
[  497.351792] [C3DEFF10] [C004FD10] kswapd+0x2d4/0x424
[  497.356767] [C3DEFFC0] [C0033E48] kthread+0xf4/0x130
[  497.361741] [C3DEFFF0] [C001093C] kernel_thread+0x44/0x60
[  497.367151] aio/0         S 00000000     0    56      5            
670    55 (L-TLB)
[  497.374832] Call Trace:
[  497.377272] [C3CADE20] [00000020] 0x20 (unreliable)
[  497.382162] [C3CADEE0] [C00083AC] __switch_to+0x28/0x40
[  497.387398] [C3CADF00] [C01F4B78] schedule+0x324/0x6bc
[  497.392547] [C3CADF40] [C002F67C] worker_thread+0x144/0x148
[  497.398128] [C3CADFC0] [C0033E48] kthread+0xf4/0x130
[  497.403102] [C3CADFF0] [C001093C] kernel_thread+0x44/0x60
[  497.408508] mtdblockd     S 00000000     0   617      1            
718     5 (L-TLB)
[  497.416191] Call Trace:
[  497.418632] [C3F27E70] [C02A0000] 0xc02a0000 (unreliable)
[  497.424043] [C3F27F30] [C00083AC] __switch_to+0x28/0x40
[  497.429278] [C3F27F50] [C01F4B78] schedule+0x324/0x6bc
[  497.434425] [C3F27F90] [C013FAAC] mtd_blktrans_thread+0x250/0x340
[  497.440534] [C3F27FF0] [C001093C] kernel_thread+0x44/0x60
[  497.445941] scsi_eh_0     D 00000000     0   670      5            
671    56 (L-TLB)
[  497.453622] Call Trace:
[  497.456062] [C3F1FDF0] [00000011] 0x11 (unreliable)
[  497.460951] [C3F1FEB0] [C00083AC] __switch_to+0x28/0x40
[  497.466187] [C3F1FED0] [C01F4B78] schedule+0x324/0x6bc
[  497.471335] [C3F1FF10] [C01F50D4] wait_for_completion+0xa0/0x150
[  497.477351] [C3F1FF50] [C016641C] command_abort+0xdc/0x118
[  497.482846] [C3F1FF60] [C0132BC0] scsi_error_handler+0x5f0/0x810
[  497.488868] [C3F1FFC0] [C0033E48] kthread+0xf4/0x130
[  497.493842] [C3F1FFF0] [C001093C] kernel_thread+0x44/0x60
[  497.499249] usb-storage   D 00000000     0   671      5            
773   670 (L-TLB)
[  497.506930] Call Trace:
[  497.509372] [C3F35A60] [C00083AC] __switch_to+0x28/0x40
[  497.514608] [C3F35A80] [C01F4B78] schedule+0x324/0x6bc
[  497.519756] [C3F35AC0] [C01F5D6C] schedule_timeout+0x6c/0xd0
[  497.525426] [C3F35B00] [C01F5C9C] io_schedule_timeout+0x30/0x54
[  497.531356] [C3F35B20] [C0050DE4] congestion_wait+0x64/0x8c
[  497.536941] [C3F35B70] [C004A9F0] throttle_vm_writeout+0x1c/0x84
[  497.542958] [C3F35B90] [C004F33C] shrink_zone+0xbb0/0xfe4
[  497.548367] [C3F35D40] [C004F8F4] try_to_free_pages+0x184/0x2cc
[  497.554298] [C3F35DB0] [C0049AA8] __alloc_pages+0x110/0x2c0
[  497.559878] [C3F35E00] [C0060F84] cache_alloc_refill+0x394/0x694
[  497.565900] [C3F35E30] [C00614A0] __kmalloc+0xc4/0xcc
[  497.570961] [C3F35E40] [C01544D0] usb_alloc_urb+0x1c/0x5c
[  497.576371] [C3F35E50] [C015520C] usb_sg_init+0x1a0/0x2f8
[  497.581779] [C3F35EA0] [C0167318] usb_stor_bulk_transfer_sg+0x8c/ 
0x138
[  497.588317] [C3F35ED0] [C0167960] usb_stor_Bulk_transport+0x140/0x310
[  497.594767] [C3F35F00] [C0167DCC] usb_stor_invoke_transport+0x2c/ 
0x344
[  497.601303] [C3F35F50] [C0166B2C] usb_stor_transparent_scsi_command 
+0x10/0x20
[  497.608449] [C3F35F60] [C0168498] usb_stor_control_thread+0x1f8/0x290
[  497.614900] [C3F35FC0] [C0033E48] kthread+0xf4/0x130
[  497.619876] [C3F35FF0] [C001093C] kernel_thread+0x44/0x60
[  497.625285] sh            D 3009C7EC     0   718      1            
787   617 (NOTLB)
[  497.632968] Call Trace:
[  497.635410] [C3C37A90] [C01339AC] scsi_run_queue+0x220/0x2e0  
(unreliable)
[  497.642216] [C3C37B50] [C00083AC] __switch_to+0x28/0x40
[  497.647452] [C3C37B70] [C01F4B78] schedule+0x324/0x6bc
[  497.652601] [C3C37BB0] [C01F5D6C] schedule_timeout+0x6c/0xd0
[  497.658272] [C3C37BF0] [C01F5C9C] io_schedule_timeout+0x30/0x54
[  497.664202] [C3C37C10] [C0050DE4] congestion_wait+0x64/0x8c
[  497.669786] [C3C37C60] [C004A9F0] throttle_vm_writeout+0x1c/0x84
[  497.675802] [C3C37C80] [C004F33C] shrink_zone+0xbb0/0xfe4
[  497.681211] [C3C37E30] [C004F8F4] try_to_free_pages+0x184/0x2cc
[  497.687141] [C3C37EA0] [C0049AA8] __alloc_pages+0x110/0x2c0
[  497.692723] [C3C37EF0] [C0049C8C] __get_free_pages+0x34/0x74
[  497.698390] [C3C37F00] [C007C3C4] sys_getcwd+0x30/0x2b0
[  497.703629] [C3C37F40] [C000FAD4] ret_from_syscall+0x0/0x38
[  497.709210] --- Exception: c01 at 0x3009c7ec
[  497.713480]     LR = 0x3009a7b0
[  497.716614] pdflush       D 00000000     0   773       
5                 671 (L-TLB)
[  497.724294] Call Trace:
[  497.726737] [C32ADD10] [C008E098] __find_get_block+0x10c/0x288  
(unreliable)
[  497.733718] [C32ADDD0] [C00083AC] __switch_to+0x28/0x40
[  497.738954] [C32ADDF0] [C01F4B78] schedule+0x324/0x6bc
[  497.744102] [C32ADE30] [C01F5D6C] schedule_timeout+0x6c/0xd0
[  497.749772] [C32ADE70] [C01F5C9C] io_schedule_timeout+0x30/0x54
[  497.755702] [C32ADE90] [C0050DE4] congestion_wait+0x64/0x8c
[  497.761285] [C32ADEE0] [C004AC74] wb_kupdate+0xf0/0x160
[  497.766520] [C32ADF50] [C004BE04] pdflush+0x16c/0x27c
[  497.771581] [C32ADFC0] [C0033E48] kthread+0xf4/0x130
[  497.776556] [C32ADFF0] [C001093C] kernel_thread+0x44/0x60
[  497.781965] time          S 3009C7EC     0   787      1   789      
788   718 (NOTLB)
[  497.789648] Call Trace:
[  497.792089] [C03A3E60] [C00083AC] __switch_to+0x28/0x40
[  497.797326] [C03A3E80] [C01F4B78] schedule+0x324/0x6bc
[  497.802474] [C03A3EC0] [C001E164] do_wait+0x700/0x100c
[  497.807630] [C03A3F40] [C000FAD4] ret_from_syscall+0x0/0x38
[  497.813210] --- Exception: c01 at 0x3009c7ec
[  497.817481]     LR = 0x3009c414
[  497.820616] trunc_test    D 300787EC     0   789     
787                     (NOTLB)
[  497.828295] Call Trace:
[  497.830737] [C19B3960] [C0160000] handshake+0x6c/0x9c (unreliable)
[  497.836939] [C19B3A20] [C00083AC] __switch_to+0x28/0x40
[  497.842175] [C19B3A40] [C01F4B78] schedule+0x324/0x6bc
[  497.847323] [C19B3A80] [C01F5D6C] schedule_timeout+0x6c/0xd0
[  497.852994] [C19B3AC0] [C01F5C9C] io_schedule_timeout+0x30/0x54
[  497.858924] [C19B3AE0] [C0050DE4] congestion_wait+0x64/0x8c
[  497.864510] [C19B3B30] [C004A9F0] throttle_vm_writeout+0x1c/0x84
[  497.870525] [C19B3B50] [C004F33C] shrink_zone+0xbb0/0xfe4
[  497.875934] [C19B3D00] [C004F8F4] try_to_free_pages+0x184/0x2cc
[  497.881864] [C19B3D70] [C0049AA8] __alloc_pages+0x110/0x2c0
[  497.887445] [C19B3DC0] [C00447F4] find_or_create_page+0x8c/0xe4
[  497.893386] [C19B3DE0] [C0090DAC] cont_prepare_write+0xac/0x32c
[  497.899321] [C19B3E20] [C00D7A50] fat_prepare_write+0x30/0x40
[  497.905077] [C19B3E30] [C008E68C] __generic_cont_expand+0xa4/0x158
[  497.911268] [C19B3E50] [C00D7254] fat_notify_change+0xf4/0x208
[  497.917109] [C19B3E80] [C007EB24] notify_change+0x1ec/0x1fc
[  497.922695] [C19B3EB0] [C0062DC0] do_truncate+0x58/0x88
[  497.927935] [C19B3F10] [C006316C] do_sys_ftruncate+0x180/0x1a8
[  497.933780] [C19B3F40] [C000FAD4] ret_from_syscall+0x0/0x38
[  497.939361] --- Exception: c01 at 0x300787ec
[  497.943634]     LR = 0x1000073c
[  497.946768] time          S 3009C7EC     0   788      1    
790           787 (NOTLB)
[  497.954450] Call Trace:
[  497.956892] [C1919E60] [C00083AC] __switch_to+0x28/0x40
[  497.962129] [C1919E80] [C01F4B78] schedule+0x324/0x6bc
[  497.967278] [C1919EC0] [C001E164] do_wait+0x700/0x100c
[  497.972431] [C1919F40] [C000FAD4] ret_from_syscall+0x0/0x38
[  497.978011] --- Exception: c01 at 0x3009c7ec
[  497.982282]     LR = 0x3009c414
[  497.985417] trunc_test    D 300787EC     0   790     
788                     (NOTLB)
[  497.993101] Call Trace:
[  497.995542] [C2BFDA00] [C0047E68] mempool_alloc+0x38/0x144  
(unreliable)
[  498.002171] [C2BFDAC0] [C00083AC] __switch_to+0x28/0x40
[  498.007406] [C2BFDAE0] [C01F4B78] schedule+0x324/0x6bc
[  498.012554] [C2BFDB20] [C01F5C48] io_schedule+0x30/0x54
[  498.017790] [C2BFDB40] [C008D01C] sync_buffer+0x68/0x7c
[  498.023026] [C2BFDB50] [C01F5E80] __wait_on_bit+0x98/0xec
[  498.028435] [C2BFDB70] [C01F5F34] out_of_line_wait_on_bit+0x60/0x74
[  498.034713] [C2BFDBC0] [C008CF3C] __wait_on_buffer+0x3c/0x4c
[  498.040382] [C2BFDBD0] [C00916F4] __bread+0xe8/0xf4
[  498.045270] [C2BFDBE0] [C00D5C24] fat_ent_bread+0x48/0xa8
[  498.050678] [C2BFDC00] [C00D6358] fat_ent_read+0x168/0x1f0
[  498.056171] [C2BFDC30] [C00D6690] fat_free_clusters+0x64/0x260
[  498.062011] [C2BFDCC0] [C00D75C4] fat_truncate+0x25c/0x334
[  498.067507] [C2BFDD30] [C0053EE4] vmtruncate+0x184/0x1a4
[  498.072833] [C2BFDD50] [C007E810] inode_setattr+0x7c/0x1a4
[  498.078329] [C2BFDD90] [C00D7314] fat_notify_change+0x1b4/0x208
[  498.084257] [C2BFDDC0] [C007EB24] notify_change+0x1ec/0x1fc
[  498.089840] [C2BFDDF0] [C0062DC0] do_truncate+0x58/0x88
[  498.095077] [C2BFDE50] [C007028C] may_open+0x1fc/0x200
[  498.100230] [C2BFDE70] [C0070380] open_namei+0xf0/0x714
[  498.105465] [C2BFDEB0] [C0063BB8] do_filp_open+0x30/0x78
[  498.110788] [C2BFDF20] [C0064018] do_sys_open+0x70/0xc0
[  498.116023] [C2BFDF40] [C000FAD4] ret_from_syscall+0x0/0x38
[  498.121605] --- Exception: c01 at 0x300787ec
[  498.125878]     LR = 0x30077580

and from 'm'

[  731.834529] Show Memory
[  731.836968] Mem-info:
[  731.839234] DMA per-cpu:
[  731.841768] CPU    0: Hot: hi:   18, btch:   3 usd:   3   Cold:  
hi:    6, btch:   1 usd:   2
[  731.850206] Active:1510 inactive:11309 dirty:7188 writeback:3330  
unstable:0 free:1009 slab:1671 mapped:110 pagetables:19
[  731.861075] DMA free:4036kB min:4096kB low:5120kB high:6144kB  
active:6040kB inactive:45236kB present:65024kB pages_scanned:292  
all_unreclaimable? no
[  731.874363] lowmem_reserve[]: 0 0
[  731.877685] DMA: 1*4kB 0*8kB 0*16kB 0*32kB 1*64kB 1*128kB 1*256kB  
1*512kB 1*1024kB 1*2048kB 0*4096kB = 4036kB
[  731.887669] Free swap:            0kB
[  731.893913] 16384 pages of RAM
[  731.896963] 798 reserved pages
[  731.900011] 10946 pages shared
[  731.903058] 0 pages swap cached

It seems like usb-storage and aio are completely off in the weeds.   
Ideas?

If you need any additional debug output let me know.

- k

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[OGAWA Hirofumi]

Kumar Gala <galak@kernel.crashing.org> writes:

>>> I usually run the following twice to get the hang state:
>>>
>>> time ./trunc_test bar 100000000 &
>>> time ./trunc_test baz 100000000 &
>>>
>>> I was wondering if anyone had any suggestions on what to poke at next
>>> to try and figure out what is going on.
>>
>> Can you check /sys/block/xxx/stat or something to make sure there is
>> no outstanding IO request?
>>
>> It seems to be no response from the lower layer...
>
> Once the system locks up I dont have any ability to do anything.

Ah, doesn't sysrq also work? If sysrq work, it can use to see IO
request state with a patch.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Kumar Gala]

On Feb 19, 2007, at 4:19 PM, OGAWA Hirofumi wrote:

> Kumar Gala <galak@kernel.crashing.org> writes:
>
>>>> I usually run the following twice to get the hang state:
>>>>
>>>> time ./trunc_test bar 100000000 &
>>>> time ./trunc_test baz 100000000 &
>>>>
>>>> I was wondering if anyone had any suggestions on what to poke at  
>>>> next
>>>> to try and figure out what is going on.
>>>
>>> Can you check /sys/block/xxx/stat or something to make sure there is
>>> no outstanding IO request?
>>>
>>> It seems to be no response from the lower layer...
>>
>> Once the system locks up I dont have any ability to do anything.
>
> Ah, doesn't sysrq also work? If sysrq work, it can use to see IO
> request state with a patch.

Yeah, got sysrq working today.  If you can point me at the patch I  
happy to apply it and get data.

- k

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[OGAWA Hirofumi]

[-- Attachment #1: Type: text/plain, Size: 593 bytes --]

Kumar Gala <galak@kernel.crashing.org> writes:

> On Feb 19, 2007, at 4:19 PM, OGAWA Hirofumi wrote:
>
>> Kumar Gala <galak@kernel.crashing.org> writes:
>>
>>> Once the system locks up I dont have any ability to do anything.
>>
>> Ah, doesn't sysrq also work? If sysrq work, it can use to see IO
>> request state with a patch.
>
> Yeah, got sysrq working today.  If you can point me at the patch I  
> happy to apply it and get data.

Ok, please try attached patch. I hope it helps you.
BTW, new sysrq is sysrq-j, and it will show disk stats.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: debug-block.patch --]
[-- Type: text/x-diff, Size: 2821 bytes --]



Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
---

 block/genhd.c        |   27 +++++++++++++++++++++++++++
 drivers/char/sysrq.c |   15 ++++++++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff -puN drivers/char/sysrq.c~debug-block drivers/char/sysrq.c
--- linux-2.6/drivers/char/sysrq.c~debug-block	2007-02-21 00:58:35.000000000 +0900
+++ linux-2.6-hirofumi/drivers/char/sysrq.c	2007-02-21 02:02:52.000000000 +0900
@@ -311,6 +311,19 @@ static struct sysrq_key_op sysrq_kill_op
 	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
 };
 
+extern void block_req_callback(struct work_struct *ignored);
+static DECLARE_WORK(block_req_work, block_req_callback);
+static void sysrq_handle_block_req(int key, struct tty_struct *tty)
+{
+	schedule_work(&block_req_work);
+}
+static struct sysrq_key_op sysrq_block_req_op = {
+	.handler	= sysrq_handle_block_req,
+	.help_msg	= "block req (j)",
+	.action_msg	= "Block Req",
+	.enable_mask	= SYSRQ_ENABLE_DUMP,
+};
+
 static void sysrq_handle_unrt(int key, struct tty_struct *tty)
 {
 	normalize_rt_tasks();
@@ -351,7 +364,7 @@ static struct sysrq_key_op *sysrq_key_ta
 	NULL,				/* g */
 	NULL,				/* h */
 	&sysrq_kill_op,			/* i */
-	NULL,				/* j */
+	&sysrq_block_req_op,		/* j */
 	&sysrq_SAK_op,			/* k */
 	NULL,				/* l */
 	&sysrq_showmem_op,		/* m */
diff -puN block/genhd.c~debug-block block/genhd.c
--- linux-2.6/block/genhd.c~debug-block	2007-02-21 01:02:13.000000000 +0900
+++ linux-2.6-hirofumi/block/genhd.c	2007-02-21 02:15:56.000000000 +0900
@@ -555,6 +555,33 @@ static struct kset_uevent_ops block_ueve
 
 decl_subsys(block, &ktype_block, &block_uevent_ops);
 
+void block_req_callback(struct work_struct *ignored)
+{
+	struct gendisk *gp;
+	char buf[BDEVNAME_SIZE];
+
+	mutex_lock(&block_subsys_lock);
+	list_for_each_entry(gp, &block_subsys.kset.list, kobj.entry) {
+		printk("%4d %4d %s %lu %lu %llu %u %lu %lu %llu %u %u %u %u:"
+		       " %u %u %u\n",
+		       gp->major, gp->first_minor, disk_name(gp, 0, buf),
+		       disk_stat_read(gp, ios[0]),
+		       disk_stat_read(gp, merges[0]),
+		       (unsigned long long)disk_stat_read(gp, sectors[0]),
+		       jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
+		       disk_stat_read(gp, ios[1]),
+		       disk_stat_read(gp, merges[1]),
+		       (unsigned long long)disk_stat_read(gp, sectors[1]),
+		       jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
+		       gp->in_flight,
+		       jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
+		       jiffies_to_msecs(disk_stat_read(gp, time_in_queue)),
+		       gp->queue->rq.count[0], gp->queue->rq.count[1],
+		       gp->queue->in_flight);
+	}
+	mutex_unlock(&block_subsys_lock);
+}
+
 /*
  * aggregate disk stat collector.  Uses the same stats that the sysfs
  * entries do, above, but makes them available through one seq_file.
_

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[OGAWA Hirofumi]

Kumar Gala <galak@kernel.crashing.org> writes:

>>> I usually run the following twice to get the hang state:
>>>
>>> time ./trunc_test bar 100000000 &
>>> time ./trunc_test baz 100000000 &
>>>
>>> I was wondering if anyone had any suggestions on what to poke at next
>>> to try and figure out what is going on.
>
> So I realized I could use sysrq to provide some more debug  
> information.  When the system locks up I get the following output  
> from 't'
>
> [  497.499249] usb-storage   D 00000000     0   671      5            
> 773   670 (L-TLB)
> [  497.506930] Call Trace:
> [  497.509372] [C3F35A60] [C00083AC] __switch_to+0x28/0x40
> [  497.514608] [C3F35A80] [C01F4B78] schedule+0x324/0x6bc
> [  497.519756] [C3F35AC0] [C01F5D6C] schedule_timeout+0x6c/0xd0
> [  497.525426] [C3F35B00] [C01F5C9C] io_schedule_timeout+0x30/0x54
> [  497.531356] [C3F35B20] [C0050DE4] congestion_wait+0x64/0x8c
> [  497.536941] [C3F35B70] [C004A9F0] throttle_vm_writeout+0x1c/0x84
> [  497.542958] [C3F35B90] [C004F33C] shrink_zone+0xbb0/0xfe4
> [  497.548367] [C3F35D40] [C004F8F4] try_to_free_pages+0x184/0x2cc
> [  497.554298] [C3F35DB0] [C0049AA8] __alloc_pages+0x110/0x2c0
> [  497.559878] [C3F35E00] [C0060F84] cache_alloc_refill+0x394/0x694
> [  497.565900] [C3F35E30] [C00614A0] __kmalloc+0xc4/0xcc
> [  497.570961] [C3F35E40] [C01544D0] usb_alloc_urb+0x1c/0x5c
> [  497.576371] [C3F35E50] [C015520C] usb_sg_init+0x1a0/0x2f8
> [  497.581779] [C3F35EA0] [C0167318] usb_stor_bulk_transfer_sg+0x8c/ 
> 0x138
> [  497.588317] [C3F35ED0] [C0167960] usb_stor_Bulk_transport+0x140/0x310
> [  497.594767] [C3F35F00] [C0167DCC] usb_stor_invoke_transport+0x2c/ 
> 0x344
> [  497.601303] [C3F35F50] [C0166B2C] usb_stor_transparent_scsi_command 
> +0x10/0x20
> [  497.608449] [C3F35F60] [C0168498] usb_stor_control_thread+0x1f8/0x290
> [  497.614900] [C3F35FC0] [C0033E48] kthread+0xf4/0x130
> [  497.619876] [C3F35FF0] [C001093C] kernel_thread+0x44/0x60
> [  497.625285] sh            D 3009C7EC     0   718      1            

[...]

> and from 'm'
>
> [  731.834529] Show Memory
> [  731.836968] Mem-info:
> [  731.839234] DMA per-cpu:
> [  731.841768] CPU    0: Hot: hi:   18, btch:   3 usd:   3   Cold:  
> hi:    6, btch:   1 usd:   2
> [  731.850206] Active:1510 inactive:11309 dirty:7188 writeback:3330  
> unstable:0 free:1009 slab:1671 mapped:110 pagetables:19
> [  731.861075] DMA free:4036kB min:4096kB low:5120kB high:6144kB  
> active:6040kB inactive:45236kB present:65024kB pages_scanned:292  
> all_unreclaimable? no
> [  731.874363] lowmem_reserve[]: 0 0
> [  731.877685] DMA: 1*4kB 0*8kB 0*16kB 0*32kB 1*64kB 1*128kB 1*256kB  
> 1*512kB 1*1024kB 1*2048kB 0*4096kB = 4036kB
> [  731.887669] Free swap:            0kB
> [  731.893913] 16384 pages of RAM
> [  731.896963] 798 reserved pages
> [  731.900011] 10946 pages shared
> [  731.903058] 0 pages swap cached
>
> It seems like usb-storage and aio are completely off in the weeds.   
> Ideas?

It seems usb-storage should remove some kmalloc and use mempool() for
urb...  Is someone working on this? And idea?
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Andrew Morton]

On Thu, 22 Feb 2007 05:18:45 +0900
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> wrote:

> Kumar Gala <galak@kernel.crashing.org> writes:
> 
> >>> I usually run the following twice to get the hang state:
> >>>
> >>> time ./trunc_test bar 100000000 &
> >>> time ./trunc_test baz 100000000 &
> >>>
> >>> I was wondering if anyone had any suggestions on what to poke at next
> >>> to try and figure out what is going on.
> >
> > So I realized I could use sysrq to provide some more debug  
> > information.  When the system locks up I get the following output  
> > from 't'
> >
> > [  497.499249] usb-storage   D 00000000     0   671      5            
> > 773   670 (L-TLB)
> > [  497.506930] Call Trace:
> > [  497.509372] [C3F35A60] [C00083AC] __switch_to+0x28/0x40
> > [  497.514608] [C3F35A80] [C01F4B78] schedule+0x324/0x6bc
> > [  497.519756] [C3F35AC0] [C01F5D6C] schedule_timeout+0x6c/0xd0
> > [  497.525426] [C3F35B00] [C01F5C9C] io_schedule_timeout+0x30/0x54
> > [  497.531356] [C3F35B20] [C0050DE4] congestion_wait+0x64/0x8c
> > [  497.536941] [C3F35B70] [C004A9F0] throttle_vm_writeout+0x1c/0x84
> > [  497.542958] [C3F35B90] [C004F33C] shrink_zone+0xbb0/0xfe4
> > [  497.548367] [C3F35D40] [C004F8F4] try_to_free_pages+0x184/0x2cc
> > [  497.554298] [C3F35DB0] [C0049AA8] __alloc_pages+0x110/0x2c0
> > [  497.559878] [C3F35E00] [C0060F84] cache_alloc_refill+0x394/0x694
> > [  497.565900] [C3F35E30] [C00614A0] __kmalloc+0xc4/0xcc
> > [  497.570961] [C3F35E40] [C01544D0] usb_alloc_urb+0x1c/0x5c
> > [  497.576371] [C3F35E50] [C015520C] usb_sg_init+0x1a0/0x2f8
> > [  497.581779] [C3F35EA0] [C0167318] usb_stor_bulk_transfer_sg+0x8c/ 
> > 0x138
> > [  497.588317] [C3F35ED0] [C0167960] usb_stor_Bulk_transport+0x140/0x310
> > [  497.594767] [C3F35F00] [C0167DCC] usb_stor_invoke_transport+0x2c/ 
> > 0x344
> > [  497.601303] [C3F35F50] [C0166B2C] usb_stor_transparent_scsi_command 
> > +0x10/0x20
> > [  497.608449] [C3F35F60] [C0168498] usb_stor_control_thread+0x1f8/0x290
> > [  497.614900] [C3F35FC0] [C0033E48] kthread+0xf4/0x130
> > [  497.619876] [C3F35FF0] [C001093C] kernel_thread+0x44/0x60
> > [  497.625285] sh            D 3009C7EC     0   718      1            
> 
> [...]
> 
> > and from 'm'
> >
> > [  731.834529] Show Memory
> > [  731.836968] Mem-info:
> > [  731.839234] DMA per-cpu:
> > [  731.841768] CPU    0: Hot: hi:   18, btch:   3 usd:   3   Cold:  
> > hi:    6, btch:   1 usd:   2
> > [  731.850206] Active:1510 inactive:11309 dirty:7188 writeback:3330  
> > unstable:0 free:1009 slab:1671 mapped:110 pagetables:19
> > [  731.861075] DMA free:4036kB min:4096kB low:5120kB high:6144kB  
> > active:6040kB inactive:45236kB present:65024kB pages_scanned:292  
> > all_unreclaimable? no
> > [  731.874363] lowmem_reserve[]: 0 0
> > [  731.877685] DMA: 1*4kB 0*8kB 0*16kB 0*32kB 1*64kB 1*128kB 1*256kB  
> > 1*512kB 1*1024kB 1*2048kB 0*4096kB = 4036kB
> > [  731.887669] Free swap:            0kB
> > [  731.893913] 16384 pages of RAM
> > [  731.896963] 798 reserved pages
> > [  731.900011] 10946 pages shared
> > [  731.903058] 0 pages swap cached
> >
> > It seems like usb-storage and aio are completely off in the weeds.   
> > Ideas?
> 
> It seems usb-storage should remove some kmalloc and use mempool() for
> urb...  Is someone working on this? And idea?

I think Pete said that we're supposed to be using GFP_NOIO in there.

Not that it'll help much: the VM calls throttle_vm_writeout() for GFP_NOIO
and GFP_NOFS allocations, which is a bug.  Because if the caller holds
locks which prevent filesystem or IO progress, we deadlock.

I'll fix the VM if someone else fixes USB ;)

Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Alan Stern]

On Wed, 21 Feb 2007, Andrew Morton wrote:

> > > It seems like usb-storage and aio are completely off in the weeds.   
> > > Ideas?
> > 
> > It seems usb-storage should remove some kmalloc and use mempool() for
> > urb...  Is someone working on this? And idea?
> 
> I think Pete said that we're supposed to be using GFP_NOIO in there.

We _are_ using it.

> Not that it'll help much: the VM calls throttle_vm_writeout() for GFP_NOIO
> and GFP_NOFS allocations, which is a bug.  Because if the caller holds
> locks which prevent filesystem or IO progress, we deadlock.
> 
> I'll fix the VM if someone else fixes USB ;)

What else needs to be fixed?

Alan Stern

Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Andrew Morton]

On Wed, 21 Feb 2007 16:22:17 -0500 (EST)
Alan Stern <stern@rowland.harvard.edu> wrote:

> On Wed, 21 Feb 2007, Andrew Morton wrote:
> 
> > > > It seems like usb-storage and aio are completely off in the weeds.   
> > > > Ideas?
> > > 
> > > It seems usb-storage should remove some kmalloc and use mempool() for
> > > urb...  Is someone working on this? And idea?
> > 
> > I think Pete said that we're supposed to be using GFP_NOIO in there.
> 
> We _are_ using it.

How admirably prompt.

> > Not that it'll help much: the VM calls throttle_vm_writeout() for GFP_NOIO
> > and GFP_NOFS allocations, which is a bug.  Because if the caller holds
> > locks which prevent filesystem or IO progress, we deadlock.
> > 
> > I'll fix the VM if someone else fixes USB ;)
> 
> What else needs to be fixed?

Would be nice if someone can confirm that this fixes it:



From: Andrew Morton <akpm@linux-foundation.org>

throttle_vm_writeout() is designed to wait for the dirty levels to subside. 
But if the caller holds IO or FS locks, we might be holding up that writeout.

So change it to take a single nap to give other devices a chance to clean some
memory, then return.

Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/writeback.h |    2 +-
 mm/page-writeback.c       |   13 +++++++++++--
 mm/vmscan.c               |    2 +-
 3 files changed, 13 insertions(+), 4 deletions(-)

diff -puN mm/vmscan.c~throttle_vm_writeout-dont-loop-on-gfp_nofs-and-gfp_noio-allocations mm/vmscan.c
--- a/mm/vmscan.c~throttle_vm_writeout-dont-loop-on-gfp_nofs-and-gfp_noio-allocations
+++ a/mm/vmscan.c
@@ -952,7 +952,7 @@ static unsigned long shrink_zone(int pri
 		}
 	}
 
-	throttle_vm_writeout();
+	throttle_vm_writeout(sc->gfp_mask);
 
 	atomic_dec(&zone->reclaim_in_progress);
 	return nr_reclaimed;
diff -puN mm/page-writeback.c~throttle_vm_writeout-dont-loop-on-gfp_nofs-and-gfp_noio-allocations mm/page-writeback.c
--- a/mm/page-writeback.c~throttle_vm_writeout-dont-loop-on-gfp_nofs-and-gfp_noio-allocations
+++ a/mm/page-writeback.c
@@ -296,11 +296,21 @@ void balance_dirty_pages_ratelimited_nr(
 }
 EXPORT_SYMBOL(balance_dirty_pages_ratelimited_nr);
 
-void throttle_vm_writeout(void)
+void throttle_vm_writeout(gfp_t gfp_mask)
 {
 	long background_thresh;
 	long dirty_thresh;
 
+	if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {
+		/*
+		 * The caller might hold locks which can prevert IO completion
+		 * or progress in the filesystem.  So we cannot just sit here
+		 * waiting for IO to complete.
+		 */
+		congestion_wait(WRITE, HZ/10);
+		return;
+	}
+
         for ( ; ; ) {
 		get_dirty_limits(&background_thresh, &dirty_thresh, NULL);
 
@@ -317,7 +327,6 @@ void throttle_vm_writeout(void)
         }
 }
 
-
 /*
  * writeback at least _min_pages, and keep writing until the amount of dirty
  * memory is less than the background threshold, or until we're all clean.
diff -puN include/linux/writeback.h~throttle_vm_writeout-dont-loop-on-gfp_nofs-and-gfp_noio-allocations include/linux/writeback.h
--- a/include/linux/writeback.h~throttle_vm_writeout-dont-loop-on-gfp_nofs-and-gfp_noio-allocations
+++ a/include/linux/writeback.h
@@ -84,7 +84,7 @@ static inline void wait_on_inode(struct 
 int wakeup_pdflush(long nr_pages);
 void laptop_io_completion(void);
 void laptop_sync_completion(void);
-void throttle_vm_writeout(void);
+void throttle_vm_writeout(gfp_t gfp_mask);
 
 /* These are exported to sysctl. */
 extern int dirty_background_ratio;
_

Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Alan Stern]

On Wed, 21 Feb 2007, Andrew Morton wrote:

> On Wed, 21 Feb 2007 16:22:17 -0500 (EST)
> Alan Stern <stern@rowland.harvard.edu> wrote:
> 
> > On Wed, 21 Feb 2007, Andrew Morton wrote:
> > 
> > > > > It seems like usb-storage and aio are completely off in the weeds.   
> > > > > Ideas?
> > > > 
> > > > It seems usb-storage should remove some kmalloc and use mempool() for
> > > > urb...  Is someone working on this? And idea?
> > > 
> > > I think Pete said that we're supposed to be using GFP_NOIO in there.
> > 
> > We _are_ using it.
> 
> How admirably prompt.

Shucks, we've been using it for years...

> > > Not that it'll help much: the VM calls throttle_vm_writeout() for GFP_NOIO
> > > and GFP_NOFS allocations, which is a bug.  Because if the caller holds
> > > locks which prevent filesystem or IO progress, we deadlock.
> > > 
> > > I'll fix the VM if someone else fixes USB ;)
> > 
> > What else needs to be fixed?
> 
> Would be nice if someone can confirm that this fixes it:

Not having experienced the problem, I can't confirm the fix.  However...

> +	if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {

Is that really the correct test?  I don't know enough about the memory 
management subsystem to say one way or the other.  What's special about 
having both flags set?

> +		/*
> +		 * The caller might hold locks which can prevert IO completion
--------------------------------------------------------------^  Typo

Although perhaps "prevert" is an acceptable neologism in this context.

> +		 * or progress in the filesystem.  So we cannot just sit here
> +		 * waiting for IO to complete.
> +		 */

Alan Stern

Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Andrew Morton]

On Wed, 21 Feb 2007 16:50:23 -0500 (EST)
Alan Stern <stern@rowland.harvard.edu> wrote:

> > +	if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {
> 
> Is that really the correct test?  I don't know enough about the memory 
> management subsystem to say one way or the other.  What's special about 
> having both flags set?

yup.  We're saying "if the caller is unable to take either IO locks or FS
locks, don't wait on FS or IO completion".

ie: don't wait on writeout progress unless we know that both the IO system
and the FS are able to make progress.

Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Kumar Gala]

On Feb 21, 2007, at 3:31 PM, Andrew Morton wrote:

> On Wed, 21 Feb 2007 16:22:17 -0500 (EST)
> Alan Stern <stern@rowland.harvard.edu> wrote:
>
>> On Wed, 21 Feb 2007, Andrew Morton wrote:
>>
>>>>> It seems like usb-storage and aio are completely off in the weeds.
>>>>> Ideas?
>>>>
>>>> It seems usb-storage should remove some kmalloc and use mempool 
>>>> () for
>>>> urb...  Is someone working on this? And idea?
>>>
>>> I think Pete said that we're supposed to be using GFP_NOIO in there.
>>
>> We _are_ using it.
>
> How admirably prompt.
>
>>> Not that it'll help much: the VM calls throttle_vm_writeout() for  
>>> GFP_NOIO
>>> and GFP_NOFS allocations, which is a bug.  Because if the caller  
>>> holds
>>> locks which prevent filesystem or IO progress, we deadlock.
>>>
>>> I'll fix the VM if someone else fixes USB ;)
>>
>> What else needs to be fixed?
>
> Would be nice if someone can confirm that this fixes it:

Doesn't seem to help my problem in a quick test, will get more data  
in the morning.

- k

Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Kumar Gala]

>>>> Not that it'll help much: the VM calls throttle_vm_writeout()  
>>>> for GFP_NOIO
>>>> and GFP_NOFS allocations, which is a bug.  Because if the caller  
>>>> holds
>>>> locks which prevent filesystem or IO progress, we deadlock.
>>>>
>>>> I'll fix the VM if someone else fixes USB ;)
>>>
>>> What else needs to be fixed?
>>
>> Would be nice if someone can confirm that this fixes it:
>
> Doesn't seem to help my problem in a quick test, will get more data  
> in the morning.
\x7f
Well, I didn't realize the patch you sent via mm-commits and the one  
here are actually different.  I noticed that mm-commits one has:

+       if ((gfp_mask & (__GFP_FS|__GFP_IO)) != __GFP_FS|__GFP_IO) {

vs

+       if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {

The second seems to make more sense.  I tested with the first last  
night which didn't help.

With the proper patch in place things look good.  Is this a candidate  
for 2.6.20-stable?

- k

Re: [linux-usb-devel] 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Andrew Morton]

> On Thu, 22 Feb 2007 12:20:06 -0600 Kumar Gala <galak@kernel.crashing.org> wrote:
> +       if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {
> 
> The second seems to make more sense.  I tested with the first last  
> night which didn't help.
> 
> With the proper patch in place things look good.  Is this a candidate  
> for 2.6.20-stable?

I suppose so, yes.

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Robert Hancock]

Kumar Gala wrote:
> [  497.499249] usb-storage   D 00000000     0   671      5           
> 773   670 (L-TLB)
> [  497.506930] Call Trace:
> [  497.509372] [C3F35A60] [C00083AC] __switch_to+0x28/0x40
> [  497.514608] [C3F35A80] [C01F4B78] schedule+0x324/0x6bc
> [  497.519756] [C3F35AC0] [C01F5D6C] schedule_timeout+0x6c/0xd0
> [  497.525426] [C3F35B00] [C01F5C9C] io_schedule_timeout+0x30/0x54
> [  497.531356] [C3F35B20] [C0050DE4] congestion_wait+0x64/0x8c
> [  497.536941] [C3F35B70] [C004A9F0] throttle_vm_writeout+0x1c/0x84
> [  497.542958] [C3F35B90] [C004F33C] shrink_zone+0xbb0/0xfe4
> [  497.548367] [C3F35D40] [C004F8F4] try_to_free_pages+0x184/0x2cc
> [  497.554298] [C3F35DB0] [C0049AA8] __alloc_pages+0x110/0x2c0
> [  497.559878] [C3F35E00] [C0060F84] cache_alloc_refill+0x394/0x694
> [  497.565900] [C3F35E30] [C00614A0] __kmalloc+0xc4/0xcc
> [  497.570961] [C3F35E40] [C01544D0] usb_alloc_urb+0x1c/0x5c
> [  497.576371] [C3F35E50] [C015520C] usb_sg_init+0x1a0/0x2f8
> [  497.581779] [C3F35EA0] [C0167318] usb_stor_bulk_transfer_sg+0x8c/0x138
> [  497.588317] [C3F35ED0] [C0167960] usb_stor_Bulk_transport+0x140/0x310
> [  497.594767] [C3F35F00] [C0167DCC] usb_stor_invoke_transport+0x2c/0x344
> [  497.601303] [C3F35F50] [C0166B2C] 
> usb_stor_transparent_scsi_command+0x10/0x20
> [  497.608449] [C3F35F60] [C0168498] usb_stor_control_thread+0x1f8/0x290
> [  497.614900] [C3F35FC0] [C0033E48] kthread+0xf4/0x130
> [  497.619876] [C3F35FF0] [C001093C] kernel_thread+0x44/0x60

This seems like a problem, the usb-storage thread is trying to allocate 
some memory which is ending up waiting for VM writeout, which obviously 
won't proceed since this thread is the one that needs to do this.. It 
looks like the allocation in usb_stor_bulk_transfer_sglist is done with 
GFP_NOIO, so I wonder why we're getting into this state?

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Kumar Gala]

On Feb 16, 2007, at 5:10 PM, Robert Hancock wrote:

> Kumar Gala wrote:
>> I'm seeing an issue with a stock 2.6.20 kernel running on an  
>> embedded PPC.  I've got a usb flash drive plugged in and the  
>> filesystem on the drive is vfat.  Running with 64M and no swap.
>> If I execute a series of large (100M+) ftruncate() on the disk the  
>> kernel will hang and never return.  It seems to be stuck in the  
>> idle loop().
>
> On FAT filesystems this forces the entire file contents of that  
> size to be written out with zeros. Are you sure the kernel just  
> isn't busy writing out all that data to the disk?

I'm pretty sure, seeing as if I run the test it takes maybe 20-30  
seconds to create the file if it succeeds.  However, I've weighted 10  
minutes and still no prompt.

I'm also able to break in with a HW debugger and am always in the  
idle loop.

- k

Re: 2.6.20 kernel hang with USB drive and vfat doing ftruncate

[Robert Hancock]

Kumar Gala wrote:
> I'm seeing an issue with a stock 2.6.20 kernel running on an embedded 
> PPC.  I've got a usb flash drive plugged in and the filesystem on the 
> drive is vfat.  Running with 64M and no swap.
> 
> If I execute a series of large (100M+) ftruncate() on the disk the 
> kernel will hang and never return.  It seems to be stuck in the idle 
> loop().

On FAT filesystems this forces the entire file contents of that size to 
be written out with zeros. Are you sure the kernel just isn't busy 
writing out all that data to the disk?

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/