syzbot


KASAN: unknown-crash Write in do_con_write

Status: auto-obsoleted due to no activity on 2022/09/20 22:47
Reported-by: syzbot+f182cd6b3b3fa5319c78@syzkaller.appspotmail.com
First crash: 750d, last: 719d

Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: WARNING in sysfs_warn_dup (log)
Repro: C syz .config

Fix bisection: failed (bisect log)
Patch testing requests:
Created Duration User Patch Repo Result
2022/09/20 21:29 19m upstream OK log

Sample crash report:
==================================================================
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
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2020/09/08 01:23 upstream f4d51dffc6c0 abf9ba4f .config log report syz C
* Struck through repros no longer work on HEAD.