Hello, syzbot found the following issue on:
HEAD commit: f4d51dff Linux 5.9-rc4 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1655cb35900000 kernel config: https://syzkaller.appspot.com/x/.config?x=8f5c353182ed6199 dashboard link: https://syzkaller.appspot.com/bug?extid=f182cd6b3b3fa5319c78 compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17d7617d900000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154ebbcd900000 Bisection is inconclusive: the issue happens on the oldest tested release. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10891c29900000 final oops: https://syzkaller.appspot.com/x/report.txt?x=12891c29900000 console output: https://syzkaller.appspot.com/x/log.txt?x=14891c29900000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+f182cd6b3b3fa5319...@syzkaller.appspotmail.com ================================================================== BUG: KASAN: unknown-crash in notify_write drivers/tty/vt/vt.c:263 [inline] BUG: KASAN: unknown-crash in cr drivers/tty/vt/vt.c:1517 [inline] BUG: KASAN: unknown-crash in vc_con_write_normal drivers/tty/vt/vt.c:2805 [inline] BUG: KASAN: unknown-crash in do_con_write+0x1270/0xd580 drivers/tty/vt/vt.c:2910 Write of size 8 at addr ffffc9000aa1f7a0 by task syz-executor240/10440 CPU: 1 PID: 10440 Comm: syz-executor240 Not tainted 5.9.0-rc4-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+0x1d6/0x29e lib/dump_stack.c:118 print_address_description+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 notify_write drivers/tty/vt/vt.c:263 [inline] cr drivers/tty/vt/vt.c:1517 [inline] vc_con_write_normal drivers/tty/vt/vt.c:2805 [inline] do_con_write+0x1270/0xd580 drivers/tty/vt/vt.c:2910 con_write+0x20/0x40 drivers/tty/vt/vt.c:3250 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0xcbf/0x1170 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:962 [inline] tty_write+0x593/0x940 drivers/tty/tty_io.c:1046 __kernel_write+0x1ac/0xac0 fs/read_write.c:528 write_pipe_buf+0xf9/0x150 fs/splice.c:799 splice_from_pipe_feed fs/splice.c:502 [inline] __splice_from_pipe+0x351/0x8b0 fs/splice.c:626 splice_from_pipe fs/splice.c:661 [inline] default_file_splice_write fs/splice.c:811 [inline] do_splice_from fs/splice.c:847 [inline] direct_splice_actor+0x1eb/0x2a0 fs/splice.c:1016 splice_direct_to_actor+0x4a2/0xb60 fs/splice.c:971 do_splice_direct+0x201/0x340 fs/splice.c:1059 do_sendfile+0x86d/0x1210 fs/read_write.c:1540 __do_sys_sendfile64 fs/read_write.c:1601 [inline] __se_sys_sendfile64 fs/read_write.c:1587 [inline] __x64_sys_sendfile64+0x164/0x1a0 fs/read_write.c:1587 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x446ac9 Code: e8 9c b4 02 00 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 8b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb3d5c84d18 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00000000006dbc58 RCX: 0000000000446ac9 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004 RBP: 00000000006dbc50 R08: 65732f636f72702f R09: 65732f636f72702f R10: 0800000080004103 R11: 0000000000000246 R12: 00000000006dbc5c R13: 00007fb3d5c84d20 R14: 00007fb3d5c84d20 R15: 20c49ba5e353f7cf Memory state around the buggy address: ffffc9000aa1f680: 00 00 00 00 00 77 00 00 00 77 07 00 77 00 70 07 ffffc9000aa1f700: 00 77 07 00 00 77 00 00 00 77 00 00 00 77 07 00 >ffffc9000aa1f780: 00 77 00 00 77 00 00 00 77 00 77 00 70 07 00 00 ^ ffffc9000aa1f800: 77 00 70 07 77 00 77 00 70 07 70 07 00 77 00 00 ffffc9000aa1f880: 00 77 00 00 70 07 00 00 77 00 00 00 77 00 00 00 ================================================================== --- This report 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 syzkal...@googlegroups.com. syzbot will keep track of this issue. 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 issue, for details see: https://goo.gl/tpsmEJ#testing-patches