Iinjineli zikaGoogle enegalelo kwi-kernel yeLinux Babhengeze ukuba bafumanise amakhulukhulu eMiqathango yohlanga, kwi-kernel isebenzisa i-KCSAN. Inkampani kudala isebenza kwi-AddressSanitizer ukufumana iimpazamo ezinxulumene nenkohliso yenkumbulo okanye i-UndefinedBehaviorSanitizer yokuziphatha okungachazwanga kwikhowudi.
Ngeli xesha, UGoogle ubonelela ngomtshini omtsha we "Race Conditions" weKernel kernel ebizwa ngokuba yiKCSAN (IKernel Concurrency Sanitizer). Obu buthathaka bumandla abukho mtsha. Ngapha koko Iimeko zohlanga zenzeka xa imisonto emibini okanye nangaphezulu kwinkqubo efanayo ingena kwindawo efanayo yenkumbulo ngaxeshanye, apho ubuncinci benye yokufikelela ekubhaleni, kwaye xa imisonto ingasebenzisi naliphi na iqhaga elikhethekileyo ukulawula ukufikelela kwabo kule memori.
Xa le miqathango ifezekisiwe, i-odolo yokufikelela ayimiselwanga kwaye ukubala kunokunika iziphumo ezahlukeneyo ukusuka kuhambo olunye ukuya kwelinye kuxhomekeke kulo myalelo.
Imiqathango yohlanga iqhubeka ibonwa njengeempazamo ezifanayo zokufikelela kwaye kunzima ukuziphinda nokuchonga iinkqubo ezifanayo. I-kernel yeLinux yinkqubo yesoftware enkulu, apho ukungqinisisa okunamandla kunye nokungahambelani komsonto kuxhomekeke ngakumbi kukhuphiswano.
Ezinye iimeko zokukhuphisana zinokuba zilungile, kodwa uninzi lwazo zichongwe ukuza kuthi ga ngoku zithathwa njengeempazamo.
I-Linux kernel ibonelela ngeendlela ezahlukeneyo ukunqanda nokulawula ezi ntlobo zeemeko Kuba zikhona izixhobo ezinje nge-Thread Analyzer okanye i-KTSAN (i-Kernel Thread Sanitizer) yokufumana iimpazamo ezenziwayo kwi-Linux Kernel.
Nangona kunjalo, uGoogle, onegalelo kwi-kernel yeLinux, esandula ukucetyiswa i-KCSAN, isixhobo sokujonga imeko seKernel, esifana neKTSAN.
NgokukaGoogle, i-KCSAN igxile ekufumaneni iimeko ezikhuphisanayo kwikhowudi yekernel. Esi sisixhobo sokufumana into eshukumayo esinamandla sesinye kwiKernel Thread Sanitizer (KTSAN).
Ngokwenkcazo kaGoogle, I-KCSAN isekwe kwiindawo zokujonga isampulu, ngokungafaniyo nomtshini we-KTSAN, Isitshixo esibalulekileyo sokujonga imeko ngaphambi komsitho. Izinto eziphambili ngokubaluleka kuyilo lwe-KCSAN kukusilela kweemposiso ezingezizo, ukusasazeka, kunye nokulula.
I-KCSAN isebenzisa izixhobo zokudibanisa ukufikelela kwimemori. I-KCSAN iyahambelana ne-GCC kunye ne-Clang compilers. Nge-GCC, ifuna inguqulo 7.3.0 okanye kamva kunye neClang, ifuna inguqulelo 7.0.0 okanye kamva.
Kwiprojekthi yephepha leGitHubUMarco Elver kaGoogle ubhale ukuba besebenzisa i-KCSAN kuvavanyo kwinyanga ephelileyo, bafumene kwiintsuku nje ezimbini ngaphezulu kwe-300 yeemeko ezizodwa zokukhuphisana. I-KCSAN ibonelela ngeendlela ezininzi zokukhetha ukwenza isimilo sayo.
Kudala sisebenzisa i-KCSAN ngeSyzkaller kangangeeveki ezininzi, kwaye sifumene uninzi lweebugs. Ekuqaleni kwinyanga yoMsintsi ngo-2019, sachonga ngaphezulu kwama-300 eemeko zokhuphiswano olwahlukileyo kwiintsuku nje ezimbini, utshilo.
UGoogle uthe indlela ngokubanzi isekwe kwiDathaCollider, omnye umtshini onamandla weemeko ezikhuphisanayo kwiimodyuli zekernel. Kodwa ngokungafaniyo neDathaCollider, i-KCSAN ayizisebenzisi iindawo zokujonga izixhobo, endaweni yoko ixhomekeke kwizixhobo zokudibanisa.
Amanqaku okubeka iliso aphunyezwa kusetyenziswa ikhowudi efanelekileyo egcina uhlobo, ubungakanani, kunye nedilesi yokufikelela kwifayile ende. Izibonelelo zokusebenzisa amanqaku okubeka esweni okuguquguqukayo kukuthwala kunye nokuguquguquka okukhulu ekunciphiseni ukufikelela kwindawo yokujonga enokuthi isebenze.
Nazi ezinye zeengongoma eziphambili ezenzelwe i-KCSAN kuGoogle:
- Ukwenza okuphezulu: Ixesha lokubaleka le-KCSAN lincinci kwaye alifuni ukuba kukhiye okwabelwana ngako kwilizwe kufikelelo ngalunye. Iziphumo zintsebenzo ebhetele kakhulu kuneKTSAN.
- Akukho nkumbulo yongezelelweyo: ngokweGoogle, akukho cache efunekayo. Umiliselo lwangoku lusebenzisa inani elincinci lobude ukukhowuda ulwazi lwendawo yokubeka iliso, engabalulekanga.
- Umyalelo wenkumbulo: I-KCSAN ayazi mithetho yolawulo lwe-Linux kernel memory (LKMM). Oku kunokubangela ukuba ugqatso olubalulekileyo lulahlekile (izinto ezingezizo) xa kuthelekiswa nomtshini wohlanga olungaphambi komsitho njengeKTSAN
- Ukuchaneka: NgokukaGoogle, i-KCSAN ayichanekanga kuba isebenzisa iqhinga lesampulu;
- Ifuna isichaso: Isichaso esincinci kufuneka ngaphandle kwexesha lokubaleka le-KCSAN. Kwimeko apho umphulaphuli womnyhadala wokuqala, nakuphi na ukushiyeka kukhokelela kwiimposiso ezingezizo, ezibaluleke ngokukodwa kwimeko yekernel ebandakanya iindlela zexesha lesiko.
- Ukufunyanwa kokubhala okunamandla kwezixhobo: Ngokujonga amaxabiso edatha ngexesha lokuseta ukubukela, amandla abhaliweyo avela kwizixhobo anokufunyanwa.