Hello, syzbot found the following crash on: HEAD commit: 1a147b74 Merge branch 'DSA-mtu' git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=14237713e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=46ee14d4915944bc dashboard link: https://syzkaller.appspot.com/bug?extid=67e4f16db666b1c8253c compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12237713e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10ec7c97e00000 The bug was bisected to: commit 658b0f92bc7003bc734471f61bf7cd56339eb8c3 Author: Murilo Opsfelder Araujo <muriloo@xxxxxxxxxxxxx> Date: Wed Aug 1 21:33:15 2018 +0000 powerpc/traps: Print unhandled signals in a separate function bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15979f5be00000 final crash: https://syzkaller.appspot.com/x/report.txt?x=17979f5be00000 console output: https://syzkaller.appspot.com/x/log.txt?x=13979f5be00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+67e4f16db666b1c8253c@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 658b0f92bc70 ("powerpc/traps: Print unhandled signals in a separate function") EXT4-fs warning (device sda1): ext4_da_update_reserve_space:344: ext4_da_update_reserve_space: ino 15722, used 1 with only 0 reserved data blocks ------------[ cut here ]------------ WARNING: CPU: 1 PID: 359 at fs/ext4/inode.c:348 ext4_da_update_reserve_space+0x622/0x7d0 fs/ext4/inode.c:344 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 359 Comm: kworker/u4:5 Not tainted 5.6.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) 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:174 [inline] fixup_bug arch/x86/kernel/traps.c:169 [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:ext4_da_update_reserve_space+0x622/0x7d0 fs/ext4/inode.c:348 Code: 02 00 0f 85 94 01 00 00 48 8b 7d 28 49 c7 c0 20 72 3c 88 41 56 48 c7 c1 80 60 3c 88 53 ba 58 01 00 00 4c 89 c6 e8 1e 6d 0d 00 <0f> 0b 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 0f b6 04 RSP: 0018:ffffc90002197288 EFLAGS: 00010296 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff820bf066 RDI: fffff52000432e21 RBP: ffff888086b744c8 R08: 0000000000000091 R09: ffffed1015ce6659 R10: ffffed1015ce6658 R11: ffff8880ae7332c7 R12: 0000000000000001 R13: ffff888086b74990 R14: 0000000000000000 R15: ffff888086b74a40 ext4_ext_map_blocks+0x24aa/0x37d0 fs/ext4/extents.c:4500 ext4_map_blocks+0x4cb/0x1650 fs/ext4/inode.c:622 mpage_map_one_extent fs/ext4/inode.c:2365 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2418 [inline] ext4_writepages+0x19eb/0x3080 fs/ext4/inode.c:2772 do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344 __writeback_single_inode+0x12a/0x1410 fs/fs-writeback.c:1452 writeback_sb_inodes+0x515/0xdd0 fs/fs-writeback.c:1716 wb_writeback+0x2a5/0xd90 fs/fs-writeback.c:1892 wb_do_writeback fs/fs-writeback.c:2037 [inline] wb_workfn+0x339/0x11c0 fs/fs-writeback.c:2078 process_one_work+0x94b/0x1690 kernel/workqueue.c:2266 worker_thread+0x96/0xe20 kernel/workqueue.c:2412 kthread+0x357/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 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. 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
