KASAN: user-memory-access Read in insert_char

Status: closed as dup on 2020/08/16 01:40
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+6ff38b320aa51ebe17e6@syzkaller.appspotmail.com
First crash: 2439d, last: 2299d
Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: general protection fault in insert_char (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: user-memory-access Read in insert_char 0 (2) 2019/12/10 18:00
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: user-memory-access Read in insert_char 17 syz, C done 2 2226d 2439d 1/1 fixed on 2020/08/10 10:36
linux-4.14 KASAN: user-memory-access Read in insert_char 17 syz, C error 1 2259d 2439d 0/1 upstream: reported C repro on 2019/12/10 18:41
▶ ▼ Fix bisection attempts (4)
Created Duration User Patch Repo Result
2020/05/28 19:55 0m bisect fix upstream error job log
2020/04/16 20:26 19m bisect fix upstream OK (0) job log log
2020/03/17 10:33 20m bisect fix upstream OK (0) job log log
2020/02/15 13:17 21m bisect fix upstream OK (0) job log log

Sample crash report:
==================================================================
BUG: KASAN: user-memory-access in memmove include/linux/string.h:395 [inline]
BUG: KASAN: user-memory-access in scr_memmovew include/linux/vt_buffer.h:68 [inline]
BUG: KASAN: user-memory-access in insert_char+0x206/0x400 drivers/tty/vt/vt.c:839
Read of size 212 at addr 00000000ffffff3a by task syz-executor110/9983

CPU: 0 PID: 9983 Comm: syz-executor110 Not tainted 5.5.0-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+0x5/0x41 mm/kasan/report.c:510
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
 memmove+0x24/0x50 mm/kasan/common.c:116
 memmove include/linux/string.h:395 [inline]
 scr_memmovew include/linux/vt_buffer.h:68 [inline]
 insert_char+0x206/0x400 drivers/tty/vt/vt.c:839
 csi_at drivers/tty/vt/vt.c:1964 [inline]
 do_con_trol+0x41a6/0x61b0 drivers/tty/vt/vt.c:2431
 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:00007ffe20b7f268 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004404f9
RDX: 0000000000000078 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401de0
R13: 0000000000401e70 R14: 0000000000000000 R15: 0000000000000000
==================================================================

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/12/11 13:28 upstream 6794862a16ef 101194eb .config console log report syz C ci-upstream-kasan-gce-selinux-root
2019/12/11 07:24 upstream 6794862a16ef 101194eb .config console log report syz C ci-upstream-kasan-gce-root
2019/12/10 17:59 upstream 6794862a16ef 5a5826a1 .config console log report syz C ci-upstream-kasan-gce
2019/12/23 14:58 linux-next 7ddd09fc4b74 be5c2c81 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2020/04/28 19:55 upstream 3f777e19d171 e3ecea2e .config console log report ci-upstream-kasan-gce
2020/01/16 13:17 upstream f5ae2ea6347a 3de7aabb .config console log report ci-upstream-kasan-gce-root
2020/01/14 20:14 upstream e033e7d4a808 fa12bd3c .config console log report ci-upstream-kasan-gce-root
2019/12/17 17:20 upstream ea200dec5128 a6bc9c88 .config console log report ci-upstream-kasan-gce
2019/12/16 17:24 upstream 510c9788991c b80769fc .config console log report ci-upstream-kasan-gce
2019/12/14 09:54 upstream e31736d9fae8 eef6e580 .config console log report ci-upstream-kasan-gce
2019/12/14 09:34 upstream e31736d9fae8 eef6e580 .config console log report ci-upstream-kasan-gce
2019/12/10 15:37 upstream 6794862a16ef 5a5826a1 .config console log report ci-upstream-kasan-gce
* Struck through repros no longer work on HEAD.