Hi, El mié, 9 dic 2020 a las 20:53, Denys Vlasenko (<[email protected]>) escribió: > > On Wed, Dec 9, 2020 at 10:19 AM Thomas De Schampheleire > <[email protected]> wrote: > > From: Philippe Belet <[email protected]> > > > > When mounting, in parallel, multiple loop devices (squashfs for the > > submitter's case), the following behavior can be observed: > > > > stat64(/path/to/image, {st_mode=S_IFREG|0644, st_size=4096, ...}) = 0 > > openat(AT_FDCWD, /path/to/image, O_RDWR|O_LARGEFILE) = 3 > > openat(AT_FDCWD, /dev/loop-control, O_RDWR|O_LARGEFILE|O_CLOEXEC) = 4 > > ioctl(4, LOOP_CTL_GET_FREE) = 12 > > close(4) = 0 > > openat(AT_FDCWD, /dev/loop12, O_RDWR|O_LARGEFILE) = 4 > > ioctl(4, LOOP_GET_STATUS64, {lo_offset=0, lo_number=12, > > lo_flags=LO_FLAGS_AUTOCLEAR, lo_file_name=/path/to/image, ...}) = 0 > > close(4) = 0 > > close(3) = 0 > > write(2, "mount: can't setup loop device\n", 31mount: can't setup loop > > device > > ) = 31 > > exit_group(0) = ? > > +++ exited with 0 +++ > > > > The ioctl LOOP_CTL_GET_FREE has resulted in the same result for > > a competing mount process. The subsequent ioctl LOOP_GET_STATUS64 > > fails, having succeeded for the competing mount process. Next we > > see a series of other system calls. > > > > The mount code checks the errno value of the last close() > > syscall > > No it does not. errno is not cleared to zero on successful syscalls, > it's left untouched. > > Does just this change: > > - return errno; > + return loopfd; > > fix the problem?
Yes, it seems so. At least with the given test program I get correct results with this change alone. Will you adapt directly or should I send a new patch? Thanks, Thomas _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
