在 2021/4/12 22:20, Richard Cochran 写道:
> On Mon, Apr 12, 2021 at 12:45:51PM +0000, Chen Jun wrote:
>> the correct error is covered by put_old_timex32.
>
> Well, the non-negative return code (TIME_OK, TIME_INS, etc) is
> clobbered by put_old_timex32().
>
>> Fixes: f1f1d5ebd10f ("posix-timers: Introduce a syscall for clock tuning.")
>
> This is not the correct commit for the "Fixes" tag. Please find the
> actual commit that introduced the issue.
>
> In commit f1f1d5ebd10f the code looked like this...
>
> long compat_sys_clock_adjtime(clockid_t which_clock,
> struct compat_timex __user *utp)
> {
> struct timex txc;
> mm_segment_t oldfs;
> int err, ret;
>
> err = compat_get_timex(&txc, utp);
> if (err)
> return err;
>
> oldfs = get_fs();
> set_fs(KERNEL_DS);
> ret = sys_clock_adjtime(which_clock, (struct timex __user *)
> &txc);
> set_fs(oldfs);
>
> err = compat_put_timex(utp, &txc);
> if (err)
> return err;
>
> return ret;
> }
>
f1f1d5ebd10:
Introduce compat_sys_clock_adjtime
62a6fa97684:
rename compat_sys_clock_adjtime to COMPAT_SYSCALL_DEFINE2(clock_adjtime
3a4d44b6162:
move COMPAT_SYSCALL_DEFINE2(clock_adjtime from kernel/compat.c to
kernel/time/posix-timers.c
8dabe7245bb:
COMPAT_SYSCALL_DEFINE2(clock_adjtime, ..
-> SYSCALL_DEFINE2(clock_adjtime32, ..
The implement of clock_adjtime32 is similar to compat_sys_clock_adjtime.
And I think f1f1d5ebd10 introduced the problem actually.
> Thanks,
> Richard
>
>
>
>> Signed-off-by: Chen Jun <chenjun...@huawei.com>
>> ---
>> kernel/time/posix-timers.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
>> index bf540f5a..dd5697d 100644
>> --- a/kernel/time/posix-timers.c
>> +++ b/kernel/time/posix-timers.c
>> @@ -1191,8 +1191,8 @@ SYSCALL_DEFINE2(clock_adjtime32, clockid_t,
>> which_clock,
>>
>> err = do_clock_adjtime(which_clock, &ktx);
>>
>> - if (err >= 0)
>> - err = put_old_timex32(utp, &ktx);
>> + if (err >= 0 && put_old_timex32(utp, &ktx))
>> + return -EFAULT;
>>
>> return err;
>> }
>> --
>> 2.9.4
>>
>
--
Regards
Chen Jun
