Subject: [syzbot] BUG: unable to handle kernel paging request in cap_capable

From: syzbot <[email-masked]>
Date: Wed, 04 Aug 2021 10:28:22 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    b820c114eba7 net: fec: fix MAC internal delay doesn't work
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11fbdd7a300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5e6797705e664e3b
dashboard link: https://syzkaller.appspot.com/bug?extid=79f4a8692e267bdb7227
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=127e4952300000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16fef2aa300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
BUG: unable to handle page fault for address: fffff3008f71a93b
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8445 Comm: syz-executor610 Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:cap_capable+0xa0/0x280 security/commoncap.c:83
Code: 0f 8e d3 01 00 00 41 8b ad e0 00 00 00 49 bc 00 00 00 00 00 fc ff df e8 ce ef da fd 48 8d bb e0 00 00 00 48 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 74 08 3c 03 0f 8e 64 01 00 00 44 8b bb e0 00
RSP: 0018:ffffc90001c3f9d8 EFLAGS: 00010a02
RAX: 1ffff7008f71a93b RBX: ffffb8047b8d48f8 RCX: 0000000000000000
RDX: ffff88802dad54c0 RSI: ffffffff839aad82 RDI: ffffb8047b8d49d8
RBP: 0000000000000000 R08: 0000000000000028 R09: ffffffff87f70fe6
R10: ffffffff814731be R11: 00000000000089a2 R12: dffffc0000000000
R13: ffffffff8b83b660 R14: ffff8880155fa500 R15: ffff8880155fa500
FS:  000000000105d300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff3008f71a93b CR3: 000000002789f000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 security_capable+0x5c/0xc0 security/security.c:805
 ns_capable_common kernel/capability.c:375 [inline]
 ns_capable+0x6f/0x100 kernel/capability.c:396
 add_del_if+0x9b/0x140 net/bridge/br_ioctl.c:89
 br_ioctl_stub+0x1c6/0x7f0 net/bridge/br_ioctl.c:397
 br_ioctl_call+0x5e/0xa0 net/socket.c:1092
 dev_ifsioc+0xc1f/0xf60 net/core/dev_ioctl.c:382
 dev_ioctl+0x1b9/0xee0 net/core/dev_ioctl.c:580
 sock_do_ioctl+0x18b/0x210 net/socket.c:1129
 sock_ioctl+0x2f1/0x640 net/socket.c:1232
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl fs/ioctl.c:1055 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4430a9
Code: 28 c3 e8 4a 15 00 00 66 2e 0f 1f 84 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe266e8a48 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffe266e8a58 RCX: 00000000004430a9
RDX: 0000000020000080 RSI: 00000000000089a2 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe266e8a60
R13: 00007ffe266e8a80 R14: 00000000004b8018 R15: 00000000004004b8
Modules linked in:
CR2: fffff3008f71a93b
---[ end trace 5ec5ff62110878d2 ]---
RIP: 0010:cap_capable+0xa0/0x280 security/commoncap.c:83
Code: 0f 8e d3 01 00 00 41 8b ad e0 00 00 00 49 bc 00 00 00 00 00 fc ff df e8 ce ef da fd 48 8d bb e0 00 00 00 48 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 74 08 3c 03 0f 8e 64 01 00 00 44 8b bb e0 00
RSP: 0018:ffffc90001c3f9d8 EFLAGS: 00010a02
RAX: 1ffff7008f71a93b RBX: ffffb8047b8d48f8 RCX: 0000000000000000
RDX: ffff88802dad54c0 RSI: ffffffff839aad82 RDI: ffffb8047b8d49d8
RBP: 0000000000000000 R08: 0000000000000028 R09: ffffffff87f70fe6
R10: ffffffff814731be R11: 00000000000089a2 R12: dffffc0000000000
R13: ffffffff8b83b660 R14: ffff8880155fa500 R15: ffff8880155fa500
FS:  000000000105d300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff3008f71a93b CR3: 000000002789f000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email-masked].

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches