Subject: [syzbot] BUG: unable to handle kernel access to user memory in sock_ioctl

From: syzbot <[email-masked]>
Date: Wed, 10 Mar 2021 10:28:16 -0800

Hello,

syzbot found the following issue on:

HEAD commit:    0d7588ab riscv: process: Fix no prototype for arch_dup_tas..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes
console output: https://syzkaller.appspot.com/x/log.txt?x=122c343ad00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e3c595255fb2d136
dashboard link: https://syzkaller.appspot.com/bug?extid=c23c5421600e9b454849
userspace arch: riscv64

Unfortunately, I don't have any reproducer for this issue yet.

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

Unable to handle kernel access to user memory without uaccess routines at virtual address 0000000020000300
Oops [#1]
Modules linked in:
CPU: 1 PID: 4488 Comm: syz-executor.0 Not tainted 5.12.0-rc2-syzkaller-00467-g0d7588ab9ef9 #0
Hardware name: riscv-virtio,qemu (DT)
epc : sock_ioctl+0x424/0x6ac net/socket.c:1124
 ra : sock_ioctl+0x424/0x6ac net/socket.c:1124
epc : ffffffe002aeeb3e ra : ffffffe002aeeb3e sp : ffffffe023867da0
 gp : ffffffe005d25378 tp : ffffffe007e116c0 t0 : 0000000000000000
 t1 : 0000000000000001 t2 : 0000003fb8035e44 s0 : ffffffe023867e30
 s1 : 0000000000040000 a0 : 0000000000000000 a1 : 0000000000000007
 a2 : 1ffffffc00fc22d8 a3 : ffffffe003bc1d02 a4 : 0000000000000000
 a5 : 0000000000000000 a6 : 0000000000f00000 a7 : ffffffe000082eba
 s2 : 0000000000000000 s3 : 0000000000008902 s4 : 0000000020000300
 s5 : ffffffe005d2b0d0 s6 : ffffffe010facfc0 s7 : ffffffe008e00000
 s8 : 0000000000008903 s9 : ffffffe010fad080 s10: 0000000000000000
 s11: 0000000000020000 t3 : 982de389919f6300 t4 : ffffffc401175688
 t5 : ffffffc401175691 t6 : 0000000000000007
status: 0000000000000120 badaddr: 0000000020000300 cause: 000000000000000f
Call Trace:
[<ffffffe002aeeb3e>] sock_ioctl+0x424/0x6ac net/socket.c:1124
[<ffffffe0003fdb6a>] vfs_ioctl fs/ioctl.c:48 [inline]
[<ffffffe0003fdb6a>] __do_sys_ioctl fs/ioctl.c:753 [inline]
[<ffffffe0003fdb6a>] sys_ioctl+0x5c2/0xd56 fs/ioctl.c:739
[<ffffffe000005562>] ret_from_syscall+0x0/0x2
Dumping ftrace buffer:
   (ftrace buffer empty)
---[ end trace a5f91e70f37b907b ]---

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