syzbot


general protection fault in tty_release

Status: fixed on 2020/10/05 13:12
Reported-by: syzbot+c43e2785bc2cc144ca70@syzkaller.appspotmail.com
Fix commit: 37d933e8b41b fix regression in "epoll: Keep a reference on files added to the check list"
First crash: 665d, last: 658d

Fix bisection: fixed by (bisect log) :
commit 37d933e8b41b83bb8278815e366aec5a542b7e31
Author: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed Sep 2 15:30:48 2020 +0000

  fix regression in "epoll: Keep a reference on files added to the check list"

similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-54 general protection fault in tty_release C 11 653d 665d 0/2 upstream: reported C repro on 2020/08/29 05:22
linux-4.14 general protection fault in tty_release C done 10 655d 665d 1/1 fixed on 2020/10/08 10:30

Sample crash report:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 7309 Comm: syz-executor342 Not tainted 4.19.142-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:file_tty drivers/tty/tty_io.c:180 [inline]
RIP: 0010:tty_release+0x62/0xf60 drivers/tty/tty_io.c:1650
Code: 48 c1 ea 03 80 3c 02 00 0f 85 c4 0d 00 00 48 8b 04 24 48 8b 98 90 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 bc 0d 00 00 48 8b 2b 48 c7 c2 20 0d d6 87 4c 89
RSP: 0018:ffff8880881c7dc0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81aa5392
RDX: 0000000000000000 RSI: ffffffff83a5a16d RDI: ffff8880a4261630
RBP: ffff8880a4f7fd40 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000001 R12: ffff8880a4261630
R13: ffff8880a4f7fd68 R14: ffffffff83a5a150 R15: ffff88821991a420
FS:  00007f78d56e2700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb738094000 CR3: 00000000a5dd9000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __fput+0x2ce/0x890 fs/file_table.c:278
 task_work_run+0x148/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4468a9
Code: e8 5c b3 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:00007f78d56e1db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: 0000000000000000 RBX: 00000000006dbc48 RCX: 00000000004468a9
RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000008
RBP: 00000000006dbc40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000140 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 00007fff9fc57dcf R14: 00007f78d56e29c0 R15: 20c49ba5e353f7cf
Modules linked in:
---[ end trace 05e3e96b73db6d34 ]---
RIP: 0010:file_tty drivers/tty/tty_io.c:180 [inline]
RIP: 0010:tty_release+0x62/0xf60 drivers/tty/tty_io.c:1650
Code: 48 c1 ea 03 80 3c 02 00 0f 85 c4 0d 00 00 48 8b 04 24 48 8b 98 90 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 bc 0d 00 00 48 8b 2b 48 c7 c2 20 0d d6 87 4c 89
RSP: 0018:ffff8880881c7dc0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81aa5392
RDX: 0000000000000000 RSI: ffffffff83a5a16d RDI: ffff8880a4261630
RBP: ffff8880a4f7fd40 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000001 R12: ffff8880a4261630
R13: ffff8880a4f7fd68 R14: ffffffff83a5a150 R15: ffff88821991a420
FS:  00007f78d56e2700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb7380f1028 CR3: 00000000a5dd9000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (9):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-19 2020/08/29 07:16 linux-4.19.y f6d5cb9e2c06 d5a3ae1f .config log report syz C
ci2-linux-4-19 2020/09/04 19:53 linux-4.19.y c37da90efff5 abf9ba4f .config log report syz
ci2-linux-4-19 2020/09/04 19:02 linux-4.19.y c37da90efff5 abf9ba4f .config log report syz
ci2-linux-4-19 2020/09/03 12:23 linux-4.19.y c37da90efff5 abf9ba4f .config log report syz
ci2-linux-4-19 2020/08/31 07:46 linux-4.19.y f6d5cb9e2c06 d5a3ae1f .config log report syz
ci2-linux-4-19 2020/08/29 08:28 linux-4.19.y f6d5cb9e2c06 d5a3ae1f .config log report syz
ci2-linux-4-19 2020/08/29 07:48 linux-4.19.y f6d5cb9e2c06 d5a3ae1f .config log report syz
ci2-linux-4-19 2020/08/29 06:58 linux-4.19.y f6d5cb9e2c06 d5a3ae1f .config log report syz
ci2-linux-4-19 2020/08/29 05:36 linux-4.19.y f6d5cb9e2c06 d5a3ae1f .config log report syz