Re: Linux-next: Kernel panic - not syncing: Fatal exception in interrupt - RIP: 0010:security_port_sid

From: Stephen Smalley
Date: Wed Aug 19 2020 - 11:12:53 EST

On 8/19/20 11:06 AM, Andy Shevchenko wrote:

On Wed, Aug 19, 2020 at 3:30 PM Stephen Smalley
<stephen.smalley.work@xxxxxxxxx> wrote:
On 8/19/20 6:11 AM, Naresh Kamboju wrote:

Kernel panic noticed on linux next 20200819 tag on x86_64 and i386.

Kernel panic - not syncing: Fatal exception in interrupt

metadata:
git branch: master
git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
git commit: 8eb858df0a5f6bcd371b5d5637255c987278b8c9
git describe: next-20200819
make_kernelversion: 5.9.0-rc1
kernel-config:
https://builds.tuxbuild.com/izEMrcIH10iI6m0FU7O0LA/kernel.config

crash log:
[ 3.704578] BUG: kernel NULL pointer dereference, address: 00000000000001c8
[ 3.704865] #PF: supervisor read access in kernel mode
[ 3.704865] #PF: error_code(0x0000) - not-present page
[ 3.704865] PGD 0 P4D 0
[ 3.704865] Oops: 0000 [#1] SMP NOPTI
[ 3.704865] CPU: 0 PID: 1 Comm: systemd Not tainted
5.9.0-rc1-next-20200819 #1
[ 3.704865] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.12.0-1 04/01/2014
[ 3.704865] RIP: 0010:security_port_sid+0x2f/0xb0
[ 3.704865] Code: 55 48 89 e5 41 57 49 89 ff 41 56 49 89 ce 41 55
41 89 d5 41 54 41 89 f4 53 48 8b 7f 40 e8 c9 ca 94 00 49 8b 47 40 48
8b 40 10 <48> 8b 98 c8 01 00 00 48 85 db 75 0e eb 65 48 8b 9b c0 00 00
00 48
[ 3.704865] RSP: 0018:ffffb607c0013d00 EFLAGS: 00010246
[ 3.704865] RAX: 0000000000000000 RBX: ffffffffaef076f8 RCX: ffffb607c0013d9c
[ 3.704865] RDX: 0000000000000016 RSI: 0000000000000006 RDI: ffffffffaef08d10
[ 3.704865] RBP: ffffb607c0013d28 R08: 0000000000000218 R09: 0000000000000016
[ 3.704865] R10: ffffb607c0013d9c R11: ffff988ff9665260 R12: 0000000000000006
[ 3.704865] R13: 0000000000000016 R14: ffffb607c0013d9c R15: ffffffffaef05820
[ 3.721157] FS: 00007f5ef4fec840(0000) GS:ffff988ffbc00000(0000)
knlGS:0000000000000000
[ 3.721157] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3.721157] CR2: 00000000000001c8 CR3: 000000013b04c000 CR4: 00000000003506f0
[ 3.721157] Call Trace:
[ 3.721157] sel_netport_sid+0x120/0x1e0
[ 3.721157] selinux_socket_bind+0x15a/0x250
[ 3.721157] ? _raw_spin_trylock_bh+0x42/0x50
[ 3.721157] ? __local_bh_enable_ip+0x46/0x70
[ 3.721157] ? _raw_spin_unlock_bh+0x1a/0x20
[ 3.721157] security_socket_bind+0x35/0x50
[ 3.721157] __sys_bind+0xcf/0x110
[ 3.721157] ? syscall_enter_from_user_mode+0x1f/0x1f0
[ 3.730888] ? do_syscall_64+0x14/0x50
[ 3.730888] ? trace_hardirqs_on+0x38/0xf0
[ 3.732120] __x64_sys_bind+0x1a/0x20
[ 3.732120] do_syscall_64+0x38/0x50
[ 3.732120] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 3.732120] RIP: 0033:0x7f5ef37f3057
[ 3.732120] Code: ff ff ff ff c3 48 8b 15 3f 9e 2b 00 f7 d8 64 89
02 b8 ff ff ff ff eb ba 66 2e 0f 1f 84 00 00 00 00 00 90 b8 31 00 00
00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 11 9e 2b 00 f7 d8 64 89
01 48
[ 3.738888] RSP: 002b:00007ffe638fbbb8 EFLAGS: 00000246 ORIG_RAX:
0000000000000031
[ 3.738888] RAX: ffffffffffffffda RBX: 000055833cf9ef80 RCX: 00007f5ef37f3057
[ 3.738888] RDX: 000000000000001c RSI: 000055833cf9ef80 RDI: 000000000000002b
[ 3.743930] virtio_net virtio0 enp0s3: renamed from eth0
[ 3.738888] RBP: 000000000000002b R08: 0000000000000004 R09: 0000000000000000
[ 3.738888] R10: 00007ffe638fbbe4 R11: 0000000000000246 R12: 0000000000000000
[ 3.744849] R13: 00007ffe638fbbe4 R14: 0000000000000000 R15:
000000RIP: 0010:security_port_sid0000000000
[ 3.744849] Modules linked in:
[ 3.744849] CR2: 00000000000001c8
[ 3.744849] ---[ end trace 485eaaecdce54971 ]---
[ 3.744849] RIP: 0010:security_port_sid+0x2f/0xb0
[ 3.744849] Code: 55 48 89 e5 41 57 49 89 ff 41 56 49 89 ce 41 55
41 89 d5 41 54 41 89 f4 53 48 8b 7f 40 e8 c9 ca 94 00 49 8b 47 40 48
8b 40 10 <48> 8b 98 c8 01 00 00 48 85 db 75 0e eb 65 48 8b 9b c0 00 00
00 48
[ 3.744849] RSP: 0018:ffffb607c0013d00 EFLAGS: 00010246
[ 3.744849] RAX: 0000000000000000 RBX: ffffffffaef076f8 RCX: ffffb607c0013d9c
[ 3.744849] RDX: 0000000000000016 RSI: 0000000000000006 RDI: ffffffffaef08d10
[ 3.744849] RBP: ffffb607c0013d28 R08: 0000000000000218 R09: 0000000000000016
[ 3.744849] R10: ffffb607c0013d9c R11: ffff988ff9665260 R12: 0000000000000006
[ 3.744849] R13: 0000000000000016 R14: ffffb607c0013d9c R15: ffffffffaef05820
[ 3.744849] FS: 00007f5ef4fec840(0000) GS:ffff988ffbc00000(0000)
knlGS:0000000000000000
[ 3.744849] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3.744849] CR2: 00000000000001c8 CR3: 000000013b04c000 CR4: 00000000003506f0
[ 3.7RIP: 0010:security_port_sid44849] Kernel panic - not syncing:
Fatal exception in interrupt
[ 3.744849] Kernel Offset: 0x2c000000 from 0xffffffff81000000
(relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 3.744849] ---[ end Kernel panic - not syncing: Fatal exception in
interrupt ]---

full test log link,
https://qa-reports.linaro.org/lkft/linux-next-oe/build/next-20200819/testrun/3084905/suite/linux-log-parser/test/check-kernel-panic-1682816/log

Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
+1.
Reported-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

Thank you for the report. It appears from the log that you are enabling
SELinux but not loading any policy? If that is correct, then I believe
I know the underlying cause and can create a patch.
I guess it's too far with assumptions that people are using some
monster Linux distribution or so. I have simple kernel configuration
with minimal Buildroot (busybox + uclibc) and I have got this
inconvenience.
Please, fix this. And would be nice if you may tell what commit I can
revert without wasting time on bisect to unblock my main work.

Fix can be found at:https://patchwork.kernel.org/patch/11724203/ <https://patchwork.kernel.org/patch/11724203/>