syzbot


BUG: unable to handle kernel NULL pointer dereference in mem_serial_out

Status: closed as invalid on 2020/01/07 17:02
Reported-by: syzbot+f4f1e871965064ae689e@syzkaller.appspotmail.com
First crash: 933d, last: 920d

Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: no output from test machine (log)
Repro: C syz .config
duplicates (1):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out C done 4 920d 930d 0/22 closed as dup on 2019/12/13 09:05
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 BUG: unable to handle kernel NULL pointer dereference in mem_serial_out C error 3 652d 935d 0/1 upstream: reported C repro on 2019/12/05 04:54
linux-4.14 BUG: unable to handle kernel NULL pointer dereference in mem_serial_out C inconclusive 3 748d 935d 0/1 upstream: reported C repro on 2019/12/05 02:21

Sample crash report:
BUG: kernel NULL pointer dereference, address: 0000000000000003
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD a22e1067 P4D a22e1067 PUD 818df067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 9962 Comm: syz-executor770 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline]
RIP: 0010:mem_serial_out+0x70/0x90 drivers/tty/serial/8250/8250_port.c:408
Code: e9 00 00 00 49 8d 7c 24 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 19 48 63 db 49 03 5c 24 40 <44> 88 2b 5b 41 5c 41 5d 5d c3 e8 61 45 cf fd eb c0 e8 ba 45 cf fd
RSP: 0018:ffffc90003357908 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 1ffffffff182080e RSI: ffffffff83e38076 RDI: ffffffff8c104070
RBP: ffffc90003357920 R08: ffff8880a7eda3c0 R09: ffffed10144d41c6
R10: ffffed10144d41c5 R11: ffff8880a26a0e2b R12: ffffffff8c104030
R13: 00000000000000bf R14: ffffc90003357a40 R15: ffffffff8c104188
FS:  00000000026aa880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000003 CR3: 000000009faf0000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 serial_port_out include/linux/serial_core.h:265 [inline]
 serial8250_do_startup+0x12b9/0x1cf0 drivers/tty/serial/8250/8250_port.c:2077
 serial8250_startup+0x62/0x80 drivers/tty/serial/8250/8250_port.c:2329
 uart_port_startup drivers/tty/serial/serial_core.c:219 [inline]
 uart_startup drivers/tty/serial/serial_core.c:258 [inline]
 uart_startup+0x452/0x980 drivers/tty/serial/serial_core.c:249
 uart_set_info drivers/tty/serial/serial_core.c:998 [inline]
 uart_set_info_user+0x13b4/0x1cf0 drivers/tty/serial/serial_core.c:1023
 tty_tiocsserial drivers/tty/tty_io.c:2506 [inline]
 tty_ioctl+0xf60/0x14f0 drivers/tty/tty_io.c:2648
 vfs_ioctl fs/ioctl.c:47 [inline]
 file_ioctl fs/ioctl.c:545 [inline]
 do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749
 __do_sys_ioctl fs/ioctl.c:756 [inline]
 __se_sys_ioctl fs/ioctl.c:754 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440219
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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffeed853278 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440219
RDX: 0000000020000080 RSI: 000000000000541f RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000401b30 R11: 0000000000000246 R12: 0000000000401aa0
R13: 0000000000401b30 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
CR2: 0000000000000003
---[ end trace 8879ab40d0075c1b ]---
RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline]
RIP: 0010:mem_serial_out+0x70/0x90 drivers/tty/serial/8250/8250_port.c:408
Code: e9 00 00 00 49 8d 7c 24 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 19 48 63 db 49 03 5c 24 40 <44> 88 2b 5b 41 5c 41 5d 5d c3 e8 61 45 cf fd eb c0 e8 ba 45 cf fd
RSP: 0018:ffffc90003357908 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 1ffffffff182080e RSI: ffffffff83e38076 RDI: ffffffff8c104070
RBP: ffffc90003357920 R08: ffff8880a7eda3c0 R09: ffffed10144d41c6
R10: ffffed10144d41c5 R11: ffff8880a26a0e2b R12: ffffffff8c104030
R13: 00000000000000bf R14: ffffc90003357a40 R15: ffffffff8c104188
FS:  00000000026aa880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000003 CR3: 000000009faf0000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (7):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-selinux-root 2019/12/11 00:04 upstream 6794862a16ef 5a5826a1 .config log report syz C
ci-upstream-kasan-gce-root 2019/12/10 13:50 upstream 6794862a16ef 4b83c8fb .config log report syz C
ci-upstream-kasan-gce-root 2019/12/07 02:23 upstream 7ada90eb9c7a 85f26751 .config log report syz C
ci-upstream-kasan-gce-selinux-root 2019/12/07 02:15 upstream 7ada90eb9c7a 85f26751 .config log report syz C
ci-upstream-linux-next-kasan-gce-root 2019/12/19 01:34 linux-next b9c5ef25038d 79b211f7 .config log report syz C
ci-upstream-kasan-gce-root 2019/12/17 13:42 upstream ea200dec5128 d13d7958 .config log report
ci-upstream-linux-next-kasan-gce-root 2019/12/20 01:54 linux-next 9f8535c5f75f 36650b4b .config log report