On 13/12/16 11:21, Boqun Feng wrote: > On Tue, Dec 13, 2016 at 10:56:46AM +0000, Colin King wrote: >> From: Colin Ian King <[email protected]> >> >> mask and bit are unsigned longs, so if bit is 31 we end up sign >> extending the 1 and mask ends up as 0xffffffff80000000. Fix this >> by explicitly adding integer suffix UL ensure 1 is a unsigned long >> rather than an signed int. >> > > Right, you are, and the tool is ;-) > > If @bit is greater than 32, we even got an undefined behavior in C ;-( > This is my careless mistake, thank you for finding it out and fix it! > >> Issue found with static analysis with CoverityScan, CID 1388564 >> >> Fixes: 8965c3ce4718754db ("rcu: Use leaf_node_for_each_mask_possible_cpu() >> in force_qs_rnp()") >> Signed-off-by: Colin Ian King <[email protected]> > > I think Paul only queued that for running tests and I have almost > finished a v2. I will fold your fix in my patch and add your SoB along > with mine, does that work for you?
Sure, that's good with me.
>
> TBH, this situation is kinda new to me, so if anyone has any suggestion,
> please let me know ;-)
>
> Regards,
> Boqun
>
>> ---
>> kernel/rcu/tree.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
>> index 10162ac..6ecedd8 100644
>> --- a/kernel/rcu/tree.c
>> +++ b/kernel/rcu/tree.c
>> @@ -3051,7 +3051,7 @@ static void force_qs_rnp(struct rcu_state *rsp,
>>
>> leaf_node_for_each_mask_possible_cpu(rnp, rnp->qsmask, bit, cpu)
>> if (f(per_cpu_ptr(rsp->rda, cpu), isidle, maxj))
>> - mask |= 1 << bit;
>> + mask |= 1UL << bit;
>>
>> if (mask != 0) {
>> /* Idle/offline CPUs, report (releases rnp->lock. */
>> --
>> 2.10.2
>>
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