On Wed, May 2, 2018 at 12:30 PM, Tetsuo Handa <[email protected]> wrote: > Dmitry Vyukov wrote: >> > syzbot is reporting various bugs which involve /dev/loopX. >> > Two of them >> > >> > INFO: rcu detected stall in lo_ioctl >> > >> > https://syzkaller.appspot.com/bug?id=7b49fb610af9cca78c24e9f796f2e8b0d5573997 >> > >> > general protection fault in lo_ioctl (2) >> > >> > https://syzkaller.appspot.com/bug?id=f3cfe26e785d85f9ee259f385515291d21bd80a3 >> >> /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ >> >> Now there is a repro for this one. I've pushed it to kernel mailing lists: >> >> https://groups.google.com/d/msg/syzkaller-bugs/c8KUcTAzTvA/3o_7g6-tAwAJ > > OK, thanks. But among loop related reports, this will be a dup of > "INFO: rcu detected stall in blkdev_ioctl" which already has C reproducer. > Should we merge them?
Yes, sure, I will take care of it. > INFO: rcu detected stall in blkdev_ioctl > > https://syzkaller.appspot.com/bug?id=1f7b710f4110f225aed1f4263ec2b98b8dbd472e > > general protection fault in lo_ioctl (2) > > https://syzkaller.appspot.com/bug?id=f3cfe26e785d85f9ee259f385515291d21bd80a3 > #syz dup: INFO: rcu detected stall in blkdev_ioctl > > INFO: rcu detected stall in lo_compat_ioctl > > https://syzkaller.appspot.com/bug?id=6299555c4e252b53f7a2ae2b8216cc9456c56ac0 > #syz dup: INFO: rcu detected stall in blkdev_ioctl > > INFO: rcu detected stall in lo_ioctl > > https://syzkaller.appspot.com/bug?id=7b49fb610af9cca78c24e9f796f2e8b0d5573997 > #syz dup: INFO: rcu detected stall in blkdev_ioctl > > INFO: task hung in lo_ioctl > > https://syzkaller.appspot.com/bug?id=608144371e7fc2cb6285b9ed871fb1eb817a61ce > > INFO: task hung in lo_open (2) > > https://syzkaller.appspot.com/bug?id=1f93b57f496d969efb9fb24167f6f9de5ee068fd > > possible deadlock in blkdev_reread_part > > https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d15889 > > INFO: task hung in loop_control_ioctl > > https://syzkaller.appspot.com/bug?id=61fe32c77ea00412c5149bd34649a65b7f672b5e > > WARNING in sysfs_remove_group > > https://syzkaller.appspot.com/bug?id=3f86c0edf75c86d2633aeb9dd69eccc70bc7e90b > >> >> > suggest that loop module is not thread safe. The former suggests that >> > l->lo_backing_file is forming circular loop and the latter suggests that >> > l->lo_backing_file became NULL.
