KASAN: null-ptr-deref Read in do_con_trol

Status: closed as dup on 2020/07/20 22:49
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+70b2d05eec48639a904e@syzkaller.appspotmail.com
First crash: 2374d, last: 2310d
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 (error log, bisect log)
  
▶ ▼ Duplicate of
Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported
general protection fault in do_con_write 2 syz, C done 10703 2210d 2445d
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
KASAN: null-ptr-deref Read in do_con_trol 0 (1) 2020/02/13 18:37
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: null-ptr-deref Read in do_con_trol 11 syz, C done 1 2223d 2373d 1/1 fixed on 2020/08/12 22:58
linux-4.14 KASAN: null-ptr-deref Read in do_con_trol 11 syz, C inconclusive 1 2252d 2372d 0/1 upstream: reported C repro on 2020/02/15 00:04
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2020/05/17 02:10 0m bisect fix upstream error job log
2020/04/16 20:52 19m bisect fix upstream OK (0) job log log
2020/03/17 14:56 22m bisect fix upstream OK (0) job log log

Sample crash report:
==================================================================
BUG: KASAN: null-ptr-deref in memcpy include/linux/string.h:381 [inline]
BUG: KASAN: null-ptr-deref in scr_memcpyw include/linux/vt_buffer.h:49 [inline]
BUG: KASAN: null-ptr-deref in delete_char drivers/tty/vt/vt.c:852 [inline]
BUG: KASAN: null-ptr-deref in csi_P drivers/tty/vt/vt.c:1985 [inline]
BUG: KASAN: null-ptr-deref in do_con_trol+0x3b9/0x61b0 drivers/tty/vt/vt.c:2379
Read of size 4294967294 at addr 0000000000000012 by task syz-executor031/10979

CPU: 1 PID: 10979 Comm: syz-executor031 Not tainted 5.6.0-rc1-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+0x197/0x210 lib/dump_stack.c:118
 __kasan_report.cold+0x5/0x32 mm/kasan/report.c:510
 kasan_report+0x12/0x20 mm/kasan/common.c:641
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
 memcpy+0x24/0x50 mm/kasan/common.c:127
 memcpy include/linux/string.h:381 [inline]
 scr_memcpyw include/linux/vt_buffer.h:49 [inline]
 delete_char drivers/tty/vt/vt.c:852 [inline]
 csi_P drivers/tty/vt/vt.c:1985 [inline]
 do_con_trol+0x3b9/0x61b0 drivers/tty/vt/vt.c:2379
 do_con_write.part.0+0xfd9/0x1ef0 drivers/tty/vt/vt.c:2797
 do_con_write drivers/tty/vt/vt.c:2565 [inline]
 con_write+0x46/0xd0 drivers/tty/vt/vt.c:3135
 process_output_block drivers/tty/n_tty.c:595 [inline]
 n_tty_write+0x40e/0x1080 drivers/tty/n_tty.c:2333
 do_tty_write drivers/tty/tty_io.c:962 [inline]
 tty_write+0x496/0x7f0 drivers/tty/tty_io.c:1046
 __vfs_write+0x8a/0x110 fs/read_write.c:494
 vfs_write+0x268/0x5d0 fs/read_write.c:558
 ksys_write+0x14f/0x290 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:620
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4404f9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe661a6468 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004404f9
RDX: 0000000000000078 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401de0
R13: 0000000000401e70 R14: 0000000000000000 R15: 0000000000000000
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/02/16 02:20 upstream 829e69446995 5d7b90f1 .config console log report syz C ci-upstream-kasan-gce-selinux-root
2020/02/14 18:36 upstream b19e8c684703 5d7b90f1 .config console log report syz C ci-upstream-kasan-gce-root
2020/02/13 08:32 upstream f2850dd5ee01 84f4fc8a .config console log report syz C ci-upstream-kasan-gce
2020/02/13 08:41 upstream f2850dd5ee01 84f4fc8a .config console log report syz C ci-upstream-kasan-gce-386
2020/02/13 07:53 linux-next 51d5d207918d 84f4fc8a .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2020/02/13 05:16 linux-next 51d5d207918d 84f4fc8a .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.