git - how to do bisect to find a good commit from upsteam linux kernel? -

i using bisect find commit fix s4 issue upstream kernel codes. meet confusing issue when :

git bisect  start git bisect bad  v4.8-rc1 git bisect v4.7  

it take 13 steps finish result .

but found bisect choose commits older v4.7 tag , normal ?

in opinion ,bisect should choose commits between v4.7 tag , v4.8-rc1 tag judging time line .

in opinion ,bisect should choose commits between v4.7 tag , v4.8-rc1 tag judging time line .

this not bisect do. bisect choose commits contained in tag v4.8-rc1 , not contained in tag v4.7. differ if e.g. branch created v4.6 , changes committed before v4.7 created - branch not merged v4.7. in kernel development there might lot of changes have been committed quite time before have been merged. date of commits before v4.7, changes not contained in v4.7.

it important bisect behaves way , not based on time used find commit introduced problem. can happen commit created before "good" version not contained yet.

if have commit can check in tags contained using git tag --contains <commit-hash>. tag v4.7 not part of list , explanation why commits chosen git bisect.