I tried to echo an invalid value to an unsigned long type sysctl on 4.9.0-rc6: linux:~# cat /proc/sys/vm/user_reserve_kbytes 131072 linux:~# echo -1 > /proc/sys/vm/user_reserve_kbytes linux:~# cat /proc/sys/vm/user_reserve_kbytes 131072
The echo operation got error and the value do not write to user_reserve_kbytes, however, user do not know it until checking the value again. This patch return -EINVAL when write an invalid value to unsigned long type sysctl to make user know what happened without checking its value once more, just as what proc_douintvec do. Signed-off-by: Yisheng Xie <[email protected]> --- This is a patchset after RFC, you can see the former discussion at https://lkml.org/lkml/2016/11/26/48 Any comment is more than welcome. Thanks, Yisheng Xie. --- kernel/sysctl.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 706309f..40e9285 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2485,10 +2485,14 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int sizeof(proc_wspace_sep), NULL); if (err) break; - if (neg) - continue; - if ((min && val < *min) || (max && val > *max)) - continue; + if (neg) { + err = -EINVAL; + break; + } + if ((min && val < *min) || (max && val > *max)) { + err = -EINVAL; + break; + } *i = val; } else { val = convdiv * (*i) / convmul; -- 1.7.12.4
