On Mon, 13 Apr 2020 00:50:11 -0700 syzbot <syzbot+2854d22c7dd957a6519a@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: ae46d2aa mm/gup: Let __get_user_pages_locked() return -EIN.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=12b60343e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=ca75979eeebf06c2 > dashboard link: https://syzkaller.appspot.com/bug?extid=2854d22c7dd957a6519a > 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+2854d22c7dd957a6519a@xxxxxxxxxxxxxxxxxxxxxxxxx (cc's added) Looks like the loop backing device's pagecache still has a dirty page, despite us having just run sync_blockdev(). It may well be a race of some form - do we have any description of what the test is doing? > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 8402 at mm/filemap.c:222 unaccount_page_cache_page+0x631/0xd60 mm/filemap.c:222 > Kernel panic - not syncing: panic_on_warn set ... > CPU: 1 PID: 8402 Comm: syz-executor.4 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 > panic+0x2e3/0x75c kernel/panic.c:221 > __warn.cold+0x2f/0x35 kernel/panic.c:582 > report_bug+0x27b/0x2f0 lib/bug.c:195 > fixup_bug arch/x86/kernel/traps.c:175 [inline] > fixup_bug arch/x86/kernel/traps.c:170 [inline] > do_error_trap+0x12b/0x220 arch/x86/kernel/traps.c:267 > do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:286 > invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 > RIP: 0010:unaccount_page_cache_page+0x631/0xd60 mm/filemap.c:222 > Code: 02 00 0f 85 3a 06 00 00 48 8b 1b 31 ff 48 c1 eb 03 83 e3 01 48 89 de e8 9d 01 e2 ff 48 85 db 0f 84 d9 fb ff ff e8 ff ff e1 ff <0f> 0b 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 > RSP: 0018:ffffc90001287688 EFLAGS: 00010012 > RAX: 0000000000040000 RBX: 0000000000000001 RCX: ffffc90011a34000 > RDX: 000000000000ec1b RSI: ffffffff81913191 RDI: 0000000000000007 > RBP: ffffea0001165dc0 R08: ffff88804a3ce240 R09: fffff9400022cbb9 > R10: ffffea0001165dc7 R11: fffff9400022cbb8 R12: 0000000000000000 > R13: ffff8880a3f6bbe0 R14: ffffea0001165dc0 R15: ffffea00022cd088 > delete_from_page_cache_batch+0x1a6/0xec0 mm/filemap.c:355 > truncate_inode_pages_range+0x58b/0x1760 mm/truncate.c:366 > kill_bdev+0xd1/0x100 fs/block_dev.c:87 > loop_set_status+0x315/0x1370 drivers/block/loop.c:1272 > loop_set_status_old+0x223/0x310 drivers/block/loop.c:1468 > lo_ioctl+0x308/0x1410 drivers/block/loop.c:1612 > __blkdev_driver_ioctl block/ioctl.c:322 [inline] > blkdev_ioctl+0x25b/0x660 block/ioctl.c:718 > block_ioctl+0xf9/0x140 fs/block_dev.c:1996 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 > __do_sys_ioctl fs/ioctl.c:772 [inline] > __se_sys_ioctl fs/ioctl.c:770 [inline] > __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 > do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 > entry_SYSCALL_64_after_hwframe+0x49/0xb3 > RIP: 0033:0x45c889 > 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:00007f83d100ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007f83d100b6d4 RCX: 000000000045c889 > RDX: 0000000020000440 RSI: 0000000000004c02 RDI: 0000000000000003 > RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 00000000000003f4 R14: 00000000004c6902 R15: 000000000076bf0c > Kernel Offset: disabled > Rebooting in 86400 seconds.. > > > --- > 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.
