Hello, syzbot found the following crash on: HEAD commit: 7e634208 Merge tag 'acpi-5.7-rc1-2' of git://git.kernel.or.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=169498ede00000 kernel config: https://syzkaller.appspot.com/x/.config?x=12205d036cec317f dashboard link: https://syzkaller.appspot.com/bug?extid=a8c70b7f3579fc0587dc compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17a41543e00000 The bug was bisected to: commit 71335f37c5e8ec9225285206f7f875057b9737ad Author: Peter Xu <peterx@xxxxxxxxxx> Date: Thu Apr 2 04:08:53 2020 +0000 mm/gup: allow to react to fatal signals bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17dba9b3e00000 final crash: https://syzkaller.appspot.com/x/report.txt?x=143ba9b3e00000 console output: https://syzkaller.appspot.com/x/log.txt?x=103ba9b3e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a8c70b7f3579fc0587dc@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 71335f37c5e8 ("mm/gup: allow to react to fatal signals") ===================================== WARNING: bad unlock balance detected! 5.6.0-syzkaller #0 Not tainted ------------------------------------- syz-executor.0/8429 is trying to release lock (&mm->mmap_sem) at: [<ffffffff819fbf60>] __get_user_pages_locked mm/gup.c:1366 [inline] [<ffffffff819fbf60>] __get_user_pages_remote mm/gup.c:1831 [inline] [<ffffffff819fbf60>] __get_user_pages_remote+0x540/0x740 mm/gup.c:1806 but there are no more locks to release! other info that might help us debug this: no locks held by syz-executor.0/8429. stack backtrace: CPU: 0 PID: 8429 Comm: syz-executor.0 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_locked mm/gup.c:1366 [inline] __get_user_pages_remote mm/gup.c:1831 [inline] __get_user_pages_remote+0x540/0x740 mm/gup.c:1806 pin_user_pages_remote+0x67/0xa0 mm/gup.c:2897 process_vm_rw_single_vec mm/process_vm_access.c:108 [inline] process_vm_rw_core.isra.0+0x423/0x940 mm/process_vm_access.c:218 process_vm_rw+0x21f/0x240 mm/process_vm_access.c:286 __do_sys_process_vm_writev mm/process_vm_access.c:308 [inline] __se_sys_process_vm_writev mm/process_vm_access.c:303 [inline] __x64_sys_process_vm_writev+0xdf/0x1b0 mm/process_vm_access.c:303 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c879 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:00007fa1008bac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000137 RAX: ffffffffffffffda RBX: 00007fa1008bb6d4 RCX: 000000000045c879 RDX: 0000000000000001 RSI: 0000000020c22000 RDI: 0000000000000009 RBP: 000000000076bf00 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000020c22fa0 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000085d R14: 00000000004cb1ee R15: 000000000076bf0c ------------[ cut here ]------------ DEBUG_RWSEMS_WARN_ON(tmp < 0): count = 0xffffffffffffff00, magic = 0xffff888094028338, owner = 0x3, curr 0xffff888093cbc500, list empty WARNING: CPU: 0 PID: 8429 at kernel/locking/rwsem.c:1435 __up_read kernel/locking/rwsem.c:1435 [inline] WARNING: CPU: 0 PID: 8429 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. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches