testing kernel oops

gistfile1.txt

# based on https://programmersought.com/article/30002612436/ and
# https://www.thegeekstuff.com/2013/07/write-linux-kernel-module/

cat > oops.c <<EOF
#include <linux/kernel.h>
#include <linux/module.h>
 
static int __init hello_init(void)
{
	int *p = 0;
	
	*p = 1;	
	return 0;
}
 
static void __exit hello_exit(void)
{
	return;
}
 
module_init(hello_init);
module_exit(hello_exit);
 
MODULE_LICENSE("GPL");
EOF

zypper -v in kernel-default-devel=$(uname -r | sed 's/-default//')"

cat > Makefile <<EOF
obj-m += oops.o

all:
    make -C /lib/modules/$(shell uname -r)/build -M=$(PWD) modules
clean:
    make -C /lib/modules/$(shell uname -r)/build -M=$(PWD) clean

insmod oops.ko

# ooops

sed -n '/oops/,$p' /var/crash/2021-10-29-11\:01/dmesg.txt
[ 1717.826175] oops: loading out-of-tree module taints kernel.
[ 1717.826229] oops: module verification failed: signature and/or required key missing - tainting kernel
[ 1717.826805] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 1717.826815] #PF: supervisor write access in kernel mode
[ 1717.826819] #PF: error_code(0x0002) - not-present page
[ 1717.826822] PGD 0 P4D 0 
[ 1717.826828] Oops: 0002 [#1] SMP NOPTI
[ 1717.826834] CPU: 1 PID: 12861 Comm: insmod Kdump: loaded Tainted: G           OE     N 5.3.18-24.83-default #1 SLE15-SP2
[ 1717.826839] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
[ 1717.826848] RIP: 0010:hello_init+0x5/0x1000 [oops]
[ 1717.826854] Code: Bad RIP value.
[ 1717.826857] RSP: 0018:ffffb05b8040bc98 EFLAGS: 00010246
[ 1717.826861] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 1717.826865] RDX: 00000000000015c9 RSI: 0000000000000cc0 RDI: ffffffffc06f7000
[ 1717.826869] RBP: ffffffffc06f7000 R08: ffff8a35bfcb1060 R09: ffff8a35bffd45c0
[ 1717.826889] R10: 00000000000015c9 R11: ffff8a35bffd4000 R12: ffff8a348f0fa270
[ 1717.826893] R13: 0000000000000001 R14: ffff8a34bf883a20 R15: ffffb05b8040be88
[ 1717.826898] FS:  00007faa1598bb80(0000) GS:ffff8a35bfc80000(0000) knlGS:0000000000000000
[ 1717.826901] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1717.826904] CR2: ffffffffc06f6fdb CR3: 000000004f382000 CR4: 0000000000340ee0
[ 1717.826909] Call Trace:
[ 1717.826916]  do_one_initcall+0x46/0x1f4
[ 1717.826927]  ? kmem_cache_alloc_trace+0x43/0x260
[ 1717.826930]  ? do_init_module+0x22/0x22f
[ 1717.826935]  do_init_module+0x5b/0x22f
[ 1717.826942]  load_module+0x1d6a/0x2310
[ 1717.826948]  ? ima_post_read_file+0xe2/0x120
[ 1717.826953]  ? __do_sys_finit_module+0xe9/0x110
[ 1717.826956]  __do_sys_finit_module+0xe9/0x110
[ 1717.826961]  do_syscall_64+0x5b/0x1e0
[ 1717.826966]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1717.826976] RIP: 0033:0x7faa1505f759
[ 1717.826980] Code: 00 48 81 c4 80 00 00 00 89 f0 c3 66 0f 1f 44 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 8b 0d 0f d7 2b 00 f7 d8 64 89 01 48
[ 1717.826985] RSP: 002b:00007ffe8698ef38 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 1717.826989] RAX: ffffffffffffffda RBX: 0000561acb656760 RCX: 00007faa1505f759
[ 1717.826991] RDX: 0000000000000000 RSI: 0000561ac9ec5688 RDI: 0000000000000003
[ 1717.826994] RBP: 0000561ac9ec5688 R08: 0000000000000000 R09: 00007ffe8698efc0
[ 1717.826997] R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
[ 1717.826999] R13: 0000561acb6563b0 R14: 0000000000000000 R15: 0000000000000000
[ 1717.827003] Modules linked in: oops(OENN+) af_packet xt_tcpudp ip6t_rpfilter ip6t_REJECT ipt_REJECT xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat nf_conntrack iscsi_ibft iscsi_boot_sysfs nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c iptable_mangle iptable_raw iptable_security ebtable_filter ebtables rfkill ip6table_filter ip6_tables iptable_filter ip_tables x_tables bpfilter crc32_pclmul ghash_clmulni_intel aesni_intel snd_hda_codec_generic ledtrig_audio aes_x86_64 crypto_simd iTCO_wdt iTCO_vendor_support snd_hda_intel cryptd glue_helper snd_hda_codec snd_hda_core snd_hwdep snd_pcm pcspkr snd_timer snd soundcore lpc_ich mfd_core i2c_i801 joydev virtio_balloon button ext4 crc16 mbcache jbd2 hid_generic usbhid sr_mod cdrom sd_mod ahci libahci qxl drm_kms_helper virtio_net virtio_rng net_failover failover virtio_scsi syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crc32c_intel xhci_pci xhci_hcd serio_raw
[ 1717.827033]  usbcore libata qemu_fw_cfg virtio_pci sg dm_multipath dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua scsi_mod
[ 1717.827058] Supported: No, Unsupported modules are loaded
[ 1717.827061] CR2: 0000000000000000
[ 1717.827074] disable async PF for cpu 1