Hello, syzbot found the following crash on: HEAD commit: bef7b2a7 Merge tag 'devicetree-for-5.7' of git://git.kerne.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1507d2e7e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=91b674b8f0368e69 dashboard link: https://syzkaller.appspot.com/bug?extid=291a90a202a1a4a7b0c1 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+291a90a202a1a4a7b0c1@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================== WARNING: bad unlock balance detected! 5.6.0-syzkaller #0 Not tainted ------------------------------------- syz-executor.2/13432 is trying to release lock (&mm->mmap_sem) at: [<ffffffff819f2464>] get_user_pages_unlocked+0x4a4/0x610 mm/gup.c:2032 but there are no more locks to release! other info that might help us debug this: no locks held by syz-executor.2/13432. stack backtrace: CPU: 0 PID: 13432 Comm: syz-executor.2 Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 __lock_release kernel/locking/lockdep.c:4633 [inline] lock_release+0x586/0x800 kernel/locking/lockdep.c:4941 up_read+0x79/0x750 kernel/locking/rwsem.c:1573 get_user_pages_unlocked+0x4a4/0x610 mm/gup.c:2032 __gup_longterm_unlocked mm/gup.c:2735 [inline] internal_get_user_pages_fast+0x44a/0x4e0 mm/gup.c:2776 get_user_pages_fast+0x49/0x70 mm/gup.c:2824 iov_iter_get_pages+0x29f/0x10c0 lib/iov_iter.c:1322 __bio_iov_iter_get_pages block/bio.c:989 [inline] bio_iov_iter_get_pages+0x1c6/0xa50 block/bio.c:1045 __blkdev_direct_IO fs/block_dev.c:387 [inline] blkdev_direct_IO+0x991/0x1360 fs/block_dev.c:477 generic_file_read_iter+0x30a/0x2b10 mm/filemap.c:2276 blkdev_read_iter+0x11b/0x180 fs/block_dev.c:2053 call_read_iter include/linux/fs.h:1901 [inline] aio_read+0x258/0x3b0 fs/aio.c:1543 __io_submit_one fs/aio.c:1829 [inline] io_submit_one+0xff9/0x2ec0 fs/aio.c:1878 __do_sys_io_submit fs/aio.c:1937 [inline] __se_sys_io_submit fs/aio.c:1907 [inline] __x64_sys_io_submit+0x1bd/0x540 fs/aio.c:1907 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c849 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fd221794c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 00007fd2217956d4 RCX: 000000000045c849 RDX: 00000000200000c0 RSI: 0000000000000008 RDI: 00007fd221774000 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000001f9 R14: 00000000004c422b R15: 000000000076bf0c ------------[ cut here ]------------ DEBUG_RWSEMS_WARN_ON(tmp < 0): count = 0xffffffffffffff00, magic = 0xffff8880959003f8, owner = 0x1, curr 0xffff88804e98c340, list empty WARNING: CPU: 1 PID: 13432 at kernel/locking/rwsem.c:1435 __up_read kernel/locking/rwsem.c:1435 [inline] WARNING: CPU: 1 PID: 13432 at kernel/locking/rwsem.c:1435 up_read+0x5f9/0x750 kernel/locking/rwsem.c:1574 --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.