The fix for this is in Greg KH's char-misc-linus branch. Pointing syzbot at it to verify: #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git char-misc-linus On Thu, Mar 28, 2019 at 9:14 AM syzbot wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: 1a9df9e2 Merge git://git.kernel.org/pub/scm/linux/kernel/g.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=11fed11f200000 > kernel config: https://syzkaller.appspot.com/x/.config?x=8dcdce25ea72bedf > dashboard link: https://syzkaller.appspot.com/bug?extid=f9f3f388440283da2965 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17d05637200000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1677e62f200000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+f9f3f388440283da2965@syzkaller.appspotmail.com > > binder: 7824:7824 DecRefs 0 refcount change on invalid ref 1 ret -22 > ------------[ cut here ]------------ > kernel BUG at drivers/android/binder_alloc.c:1141! > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > CPU: 1 PID: 7824 Comm: syz-executor570 Not tainted 5.1.0-rc2+ #40 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:binder_alloc_do_buffer_copy+0xd6/0x510 > drivers/android/binder_alloc.c:1141 > Code: 02 00 0f 85 20 04 00 00 4d 8b 64 24 58 49 29 dc e8 4f f4 23 fc 4c 89 > e6 4c 89 ef e8 64 f5 23 fc 4d 39 e5 76 07 e8 3a f4 23 fc <0f> 0b e8 33 f4 > 23 fc 4c 8b 75 d0 4d 29 ec 4c 89 e6 4c 89 f7 e8 41 > RSP: 0018:ffff88808b497550 EFLAGS: 00010293 > RAX: ffff88808620e540 RBX: 0000000020001000 RCX: ffffffff854c7d3c > RDX: 0000000000000000 RSI: ffffffff854c7d46 RDI: 0000000000000006 > RBP: ffff88808b4975d0 R08: ffff88808620e540 R09: 0000000000000028 > R10: ffffed1011692f01 R11: ffff88808b49780f R12: 0000000000000008 > R13: 0000000000000028 R14: ffff888088a0cb10 R15: 0000000000000000 > FS: 00000000006de940(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000004c4d28 CR3: 0000000090d8e000 CR4: 00000000001406e0 > Call Trace: > binder_alloc_copy_from_buffer+0x37/0x42 drivers/android/binder_alloc.c:1187 > binder_get_object+0xc3/0x200 drivers/android/binder.c:2062 > binder_transaction+0x2b4a/0x6690 drivers/android/binder.c:3231 > binder_thread_write+0x87e/0x2820 drivers/android/binder.c:3781 > binder_ioctl_write_read drivers/android/binder.c:4825 [inline] > binder_ioctl+0x1033/0x183b drivers/android/binder.c:5002 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:509 [inline] > do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696 > ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 > __do_sys_ioctl fs/ioctl.c:720 [inline] > __se_sys_ioctl fs/ioctl.c:718 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 > do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x445f19 > Code: e8 7c e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 db cb fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007fffeaa7b578 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000445f19 > RDX: 0000000020000240 RSI: 00000000c0306201 RDI: 0000000000000003 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000403010 > R10: 00007fffeaa7b0d0 R11: 0000000000000246 R12: 0000000000000000 > R13: 0000000000403010 R14: 0000000000000000 R15: 0000000000000000 > Modules linked in: > ---[ end trace 0f3d90ce4ca56ff6 ]--- > RIP: 0010:binder_alloc_do_buffer_copy+0xd6/0x510 > drivers/android/binder_alloc.c:1141 > Code: 02 00 0f 85 20 04 00 00 4d 8b 64 24 58 49 29 dc e8 4f f4 23 fc 4c 89 > e6 4c 89 ef e8 64 f5 23 fc 4d 39 e5 76 07 e8 3a f4 23 fc <0f> 0b e8 33 f4 > 23 fc 4c 8b 75 d0 4d 29 ec 4c 89 e6 4c 89 f7 e8 41 > RSP: 0018:ffff88808b497550 EFLAGS: 00010293 > RAX: ffff88808620e540 RBX: 0000000020001000 RCX: ffffffff854c7d3c > RDX: 0000000000000000 RSI: ffffffff854c7d46 RDI: 0000000000000006 > RBP: ffff88808b4975d0 R08: ffff88808620e540 R09: 0000000000000028 > R10: ffffed1011692f01 R11: ffff88808b49780f R12: 0000000000000008 > R13: 0000000000000028 R14: ffff888088a0cb10 R15: 0000000000000000 > FS: 00000000006de940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000004c4d28 CR3: 0000000090d8e000 CR4: 00000000001406f0 > > > --- > 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@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches