syzbot


BUG: unable to handle kernel NULL pointer dereference in ep_item_poll

Status: fixed on 2018/07/09 18:05
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+57727883dbad76db2ef0@syzkaller.appspotmail.com
Fix commit: e88958e6369a net: handle NULL ->poll gracefully
First crash: 2187d, last: 2187d
Discussions (1)
Title Replies (including bot) Last reply
BUG: unable to handle kernel NULL pointer dereference in ep_item_poll 0 (2) 2018/06/29 07:35

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)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
PGD 1d8d72067 P4D 1d8d72067 PUD 1d93f7067 PMD 0 
Oops: 0010 [#1] SMP KASAN
CPU: 1 PID: 4562 Comm: syz-executor213 Not tainted 4.18.0-rc2+ #121
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:          (null)
Code: Bad RIP value.
RSP: 0018:ffff8801abe9f568 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8801a7b3c940 RCX: ffffffff85ec9112
RDX: ffff8801abe9f7c0 RSI: ffff8801a7b3c940 RDI: ffff8801adb2d0c0
RBP: ffff8801abe9f610 R08: ffff8801d880c1c0 R09: ffffed003b5e46d6
R10: ffffed003b5e46d6 R11: ffff8801daf236b3 R12: ffff8801abe9f7c0
R13: ffff8801adb2d0c0 R14: ffffffff8818a920 R15: ffff8801d8e0ab00
FS:  0000000000b96880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d8d75000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 vfs_poll include/linux/poll.h:86 [inline]
 ep_item_poll.isra.14+0x15c/0x400 fs/eventpoll.c:887
 ep_insert+0x6c1/0x1c20 fs/eventpoll.c:1459
 __do_sys_epoll_ctl fs/eventpoll.c:2113 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:1999 [inline]
 __x64_sys_epoll_ctl+0xf00/0x10a0 fs/eventpoll.c:1999
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x43fce9
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 6b 45 00 00 c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007ffdf67ca318 EFLAGS: 00000217 ORIG_RAX: 00000000000000e9
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fce9
RDX: 0000000000000003 RSI: 0000000000000001 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000020000180 R11: 0000000000000217 R12: 0000000000401610
R13: 00000000004016a0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
CR2: 0000000000000000
---[ end trace 60ccf944aa06e109 ]---
RIP: 0010:          (null)
Code: Bad RIP value.
RSP: 0018:ffff8801abe9f568 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8801a7b3c940 RCX: ffffffff85ec9112
RDX: ffff8801abe9f7c0 RSI: ffff8801a7b3c940 RDI: ffff8801adb2d0c0
RBP: ffff8801abe9f610 R08: ffff8801d880c1c0 R09: ffffed003b5e46d6
R10: ffffed003b5e46d6 R11: ffff8801daf236b3 R12: ffff8801abe9f7c0
R13: ffff8801adb2d0c0 R14: ffffffff8818a920 R15: ffff8801d8e0ab00
FS:  0000000000b96880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d8d75000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/06/29 14:19 upstream 90368a37fbbe dba0b50e .config console log report syz C ci-upstream-kasan-gce
2018/06/29 13:53 upstream 90368a37fbbe dba0b50e .config console log report syz C ci-upstream-kasan-gce
2018/06/29 13:08 upstream 90368a37fbbe dba0b50e .config console log report syz C ci-upstream-kasan-gce
2018/06/29 09:03 upstream 90368a37fbbe dba0b50e .config console log report syz C ci-upstream-kasan-gce
2018/06/29 07:34 upstream 90368a37fbbe dba0b50e .config console log report syz C ci-upstream-kasan-gce-root
2018/06/29 13:11 upstream 90368a37fbbe dba0b50e .config console log report syz ci-upstream-kasan-gce-386
2018/06/29 12:36 upstream 90368a37fbbe dba0b50e .config console log report syz ci-upstream-kasan-gce-386
2018/06/29 12:03 upstream 90368a37fbbe dba0b50e .config console log report syz ci-upstream-kasan-gce-386
2018/06/29 08:49 upstream 90368a37fbbe dba0b50e .config console log report syz ci-upstream-kasan-gce-386
2018/06/29 13:17 upstream 90368a37fbbe dba0b50e .config console log report ci-upstream-kasan-gce-root
2018/06/29 11:52 upstream 90368a37fbbe dba0b50e .config console log report ci-upstream-kasan-gce-root
2018/06/29 08:32 upstream 90368a37fbbe dba0b50e .config console log report ci-upstream-kasan-gce-root
2018/06/29 05:24 upstream 90368a37fbbe dba0b50e .config console log report ci-upstream-kasan-gce-root
2018/06/29 02:53 upstream 90368a37fbbe dba0b50e .config console log report ci-upstream-kasan-gce
2018/06/29 06:51 upstream 90368a37fbbe dba0b50e .config console log report ci-upstream-kasan-gce-386
* Struck through repros no longer work on HEAD.