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08e136ebd1
loop_set_status() is allowed to change the loop device while there are other openers of the device, even exclusive ones. In this case, it causes a KASAN: slab-out-of-bounds Read in ext4_search_dir(), since when looking for an entry in an inlined directory, e_value_offs is changed underneath the filesystem by loop_set_status(). Fix the problem by forbidding loop_set_status() from modifying the loop device while there are exclusive openers of the device. This is similar to the fix in loop_configure() by commit33ec3e53e7("loop: Don't change loop device under exclusive opener") alongside commitecbe6bc000("block: use bd_prepare_to_claim directly in the loop driver"). Reported-by: syzbot+3ee481e21fd75e14c397@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3ee481e21fd75e14c397 Tested-by: syzbot+3ee481e21fd75e14c397@syzkaller.appspotmail.com Tested-by: Yongpeng Yang <yangyongpeng@xiaomi.com> Signed-off-by: Raphael Pinsonneault-Thibeault <rpthibeault@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>