On 06/12/2012 02:17 PM, Jeff Layton wrote:
> On Tue, 12 Jun 2012 13:51:06 +0200
> harald@xxxxxxxxxx wrote:
>
>> From: Harald Hoyer <harald@xxxxxxxxxx>
>>
>> PR_CAPBSET_DROP can return EINVAL, if an older kernel does support
>> some capabilities, which are defined by CAP_LAST_CAP, which results in
>> a failure of the service.
>>
>> For example kernel 3.4 errors on CAP_EPOLLWAKEUP, which was newly
>> introduced in 3.5.
>>
>> So, for future capabilities, we clear until we get an EINVAL for
>> PR_CAPBSET_READ.
>> ---
>> support/nsm/file.c | 2 +-
>> utils/nfsdcld/nfsdcld.c | 4 ++--
>> 2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/support/nsm/file.c b/support/nsm/file.c
>> index 5476446..4711c2c 100644
>> --- a/support/nsm/file.c
>> +++ b/support/nsm/file.c
>> @@ -386,7 +386,7 @@ prune_bounding_set(void)
>> }
>>
>> /* prune the bounding set to nothing */
>> - for (i = 0; i <= CAP_LAST_CAP; ++i) {
>> + for (i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >=0 ; ++i) {
>> ret = prctl(PR_CAPBSET_DROP, i, 0, 0, 0);
>> if (ret) {
>> xlog(L_ERROR, "Unable to prune capability %lu from "
>> diff --git a/utils/nfsdcld/nfsdcld.c b/utils/nfsdcld/nfsdcld.c
>> index e7af4e3..473d069 100644
>> --- a/utils/nfsdcld/nfsdcld.c
>> +++ b/utils/nfsdcld/nfsdcld.c
>> @@ -102,8 +102,8 @@ cld_set_caps(void)
>> }
>>
>> /* prune the bounding set to nothing */
>> - for (i = 0; i <= CAP_LAST_CAP; ++i) {
>> - ret = prctl(PR_CAPBSET_DROP, i);
>> + for (i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0 ; ++i) {
>> + ret = prctl(PR_CAPBSET_DROP, i, 0, 0, 0);
>> if (ret) {
>> xlog(L_ERROR, "Unable to prune capability %lu from "
>> "bounding set: %m", i);
>
> Thanks, looks like a reasonable method. Did you find this by
> inspection, or did you or someone else hit the problem?
>
> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
>
I am currently running rawhide with kernel 3.4.0 and rpc.statd failed.
rpc.statd[19338]: Unable to prune capability 36 from bounding set: Invalid argument
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