I test "proc: only require mm_struct for writing" fixed my cm14.1 problem. 2021-06-16 2:19 GMT+08:00, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>: > On Mon, Jun 14, 2021 at 6:55 PM youling 257 <youling257@xxxxxxxxx> wrote: >> >> if try to find problem on userspace, i used linux 5.13rc6 on old >> android 7 cm14.1, not aosp android 11. >> http://git.osdn.net/view?p=android-x86/system-core.git;a=blob;f=init/service.cpp;h=a5334f447fc2fc34453d2f6a37523bedccadc690;hb=refs/heads/cm-14.1-x86#l457 >> >> 457 if (!seclabel_.empty()) { >> 458 if (setexeccon(seclabel_.c_str()) < 0) { >> 459 ERROR("cannot setexeccon('%s'): %s\n", >> 460 seclabel_.c_str(), strerror(errno)); >> 461 _exit(127); >> 462 } >> 463 } > > I have no idea where the cm14.1 libraries are. Does anybody know where > the matching source code for setexeccon() would be? > > For me - obviously not on cm14.1 - all "setexeccon()" does is > > n = openat(AT_FDCWD, "/proc/thread-self/attr/exec", O_RDWR|O_CLOEXEC) > write(n, string, len) > close(n) > > and if that fails, it would seem to indicate that proc_mem_open() > failed. Which would be mm_access() failing. But I don't see how that > can be the case, because mm_access() explicitly allows "mm == > current->mm" (which the above clearly should be). > > youling, can you double-check with the current -git tree? But as far > as I can tell, my minimal patch is exactly the same as Kees' patch > (just smaller and simpler). > > Kees, do you see anything? > > Linus >
