syzbot


BUG: unable to handle kernel NULL pointer dereference in mem_serial_out

Status: upstream: reported C repro on 2019/12/05 02:21
Reported-by: syzbot+cde39bcdf34a64d68cea@syzkaller.appspotmail.com
First crash: 1661d, last: 1475d
Fix bisection the fix commit could be any of (bisect log):
  a844dc4c5442 Linux 4.14.158
  4139fb08c05f Linux 4.14.187
  
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 1378d 1661d 0/1 upstream: reported C repro on 2019/12/05 04:54
upstream BUG: unable to handle kernel NULL pointer dereference in mem_serial_out serial C done 7 1646d 1659d 0/27 closed as invalid on 2020/01/07 17:02
Last patch testing requests (4)
Created Duration User Patch Repo Result
2023/01/23 16:32 14m retest repro linux-4.14.y report log
2023/01/23 15:32 14m retest repro linux-4.14.y report log
2022/09/06 11:27 10m retest repro linux-4.14.y report log
2022/09/06 10:27 11m retest repro linux-4.14.y report log
Fix bisection attempts (7)
Created Duration User Patch Repo Result
2020/07/08 15:44 30m bisect fix linux-4.14.y job log (2)
2020/06/08 15:21 23m bisect fix linux-4.14.y job log (0) log
2020/05/09 14:54 26m bisect fix linux-4.14.y job log (0) log
2020/04/09 14:30 23m bisect fix linux-4.14.y job log (0) log
2020/03/10 14:04 26m bisect fix linux-4.14.y job log (0) log
2020/02/09 13:40 24m bisect fix linux-4.14.y job log (0) log
2020/01/10 13:13 25m bisect fix linux-4.14.y job log (0) log

Sample crash report:
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
audit: type=1400 audit(1575977990.860:36): avc:  denied  { map } for  pid=7003 comm="syz-executor321" path="/root/syz-executor321844021" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
BUG: unable to handle kernel NULL pointer dereference at 0000000000000003
IP: writeb arch/x86/include/asm/io.h:65 [inline]
IP: mem_serial_out+0x70/0x90 drivers/tty/serial/8250/8250_port.c:408
PGD 93226067 P4D 93226067 PUD a8688067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 7003 Comm: syz-executor321 Not tainted 4.14.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88809ff76680 task.stack: ffff888082ea8000
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
RSP: 0018:ffff888082eaf988 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 1ffffffff14911af RSI: 0000000000000003 RDI: ffffffff8a488d78
RBP: ffff888082eaf9a0 R08: ffff88809ff76680 R09: ffff88809ff76f48
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8a488d38
R13: 00000000000000bf R14: 000000000000000a R15: ffffffff8a488d88
FS:  000000000140c880(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000003 CR3: 0000000086acd000 CR4: 00000000001406f0
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+0x1120/0x1d80 drivers/tty/serial/8250/8250_port.c:2140
 serial8250_startup+0x5c/0x80 drivers/tty/serial/8250/8250_port.c:2411
 uart_port_startup drivers/tty/serial/serial_core.c:231 [inline]
 uart_startup.part.0+0x2e9/0x720 drivers/tty/serial/serial_core.c:270
 uart_startup drivers/tty/serial/serial_core.c:267 [inline]
 uart_set_info drivers/tty/serial/serial_core.c:1010 [inline]
 uart_set_info_user drivers/tty/serial/serial_core.c:1038 [inline]
 uart_ioctl+0x12e9/0x2610 drivers/tty/serial/serial_core.c:1361
 tty_ioctl+0x841/0x1320 drivers/tty/tty_io.c:2661
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x440219
RSP: 002b:00007ffd1863b348 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
Code: 24 d1 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 f1 65 37 fe eb c0 e8 4a 66 37 
RIP: writeb arch/x86/include/asm/io.h:65 [inline] RSP: ffff888082eaf988
RIP: mem_serial_out+0x70/0x90 drivers/tty/serial/8250/8250_port.c:408 RSP: ffff888082eaf988
CR2: 0000000000000003
---[ end trace cf06acb014bfcdbb ]---

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/12/10 11:42 linux-4.14.y a844dc4c5442 4b83c8fb .config console log report syz C ci2-linux-4-14
2019/12/05 02:20 linux-4.14.y fbc5fe7a54d0 b2088328 .config console log report syz C ci2-linux-4-14
2019/12/11 13:13 linux-4.14.y a844dc4c5442 101194eb .config console log report ci2-linux-4-14
* Struck through repros no longer work on HEAD.