2010-11-03 17:56:54

by Fengguang Wu

Subject: [PATCH] vmstat: fix offset calculation on void*

Fix regression introduced by commit 79da826aee6.

BUG: unable to handle kernel paging request at 07c06d16
IP: [<c050c336>] strnlen+0x6/0x20

Call Trace:
[<c050a249>] ? string+0x39/0xe0
[<c042be6b>] ? __wake_up_common+0x4b/0x80
[<c050afcc>] ? vsnprintf+0x1ec/0x380
[<c04b380e>] ? seq_printf+0x2e/0x60
[<c04829a6>] ? vmstat_show+0x26/0x30
[<c04b3bb6>] ? seq_read+0xa6/0x380
[<c04b3b10>] ? seq_read+0x0/0x380
[<c04d5d2f>] ? proc_reg_read+0x5f/0x90
[<c049c4a1>] ? vfs_read+0xa1/0x140
[<c04d5cd0>] ? proc_reg_read+0x0/0x90
[<c049c981>] ? sys_read+0x41/0x70
[<c0402bd0>] ? sysenter_do_call+0x12/0x26


CC: Tetsuo Handa <[email protected]>
CC: Michael Rubin <[email protected]>
Signed-off-by: Wu Fengguang <[email protected]>
---

Hopefully Tetsuo can test it soon, thanks!

mm/vmstat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-2.6.orig/mm/vmstat.c 2010-11-04 01:49:12.000000000 +0800
+++ linux-2.6/mm/vmstat.c 2010-11-04 01:49:23.000000000 +0800
@@ -949,7 +949,7 @@ static void *vmstat_start(struct seq_fil
v[PGPGIN] /= 2; /* sectors -> kbytes */
v[PGPGOUT] /= 2;
#endif
- return m->private + *pos;
+ return (unsigned long *)m->private + *pos;
}

static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)

2010-11-09 03:24:57

by KOSAKI Motohiro

Subject: Re: [PATCH] vmstat: fix offset calculation on void*

> Fix regression introduced by commit 79da826aee6.
>
> BUG: unable to handle kernel paging request at 07c06d16
> IP: [<c050c336>] strnlen+0x6/0x20
>
> Call Trace:
> [<c050a249>] ? string+0x39/0xe0
> [<c042be6b>] ? __wake_up_common+0x4b/0x80
> [<c050afcc>] ? vsnprintf+0x1ec/0x380
> [<c04b380e>] ? seq_printf+0x2e/0x60
> [<c04829a6>] ? vmstat_show+0x26/0x30
> [<c04b3bb6>] ? seq_read+0xa6/0x380
> [<c04b3b10>] ? seq_read+0x0/0x380
> [<c04d5d2f>] ? proc_reg_read+0x5f/0x90
> [<c049c4a1>] ? vfs_read+0xa1/0x140
> [<c04d5cd0>] ? proc_reg_read+0x0/0x90
> [<c049c981>] ? sys_read+0x41/0x70
> [<c0402bd0>] ? sysenter_do_call+0x12/0x26
>
>
> CC: Tetsuo Handa <[email protected]>
> CC: Michael Rubin <[email protected]>
> Signed-off-by: Wu Fengguang <[email protected]>
> ---
>
> Hopefully Tetsuo can test it soon, thanks!
>
> mm/vmstat.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- linux-2.6.orig/mm/vmstat.c 2010-11-04 01:49:12.000000000 +0800
> +++ linux-2.6/mm/vmstat.c 2010-11-04 01:49:23.000000000 +0800
> @@ -949,7 +949,7 @@ static void *vmstat_start(struct seq_fil
> v[PGPGIN] /= 2; /* sectors -> kbytes */
> v[PGPGOUT] /= 2;
> #endif
> - return m->private + *pos;
> + return (unsigned long *)m->private + *pos;
> }
>
> static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)

Good catch!
Reviewed-by: KOSAKI Motohiro <[email protected]>