Carecter Device Driver

shub.sharma007

While allocating the size for the quantum of Qset pointer variable, this kind of bug occuring everytime.
Please give an explanation for this kind of bugs

[38913.266017] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[38913.266032] IP: creatDev+0x59/0xec [allocmemory]
[38913.266035] PGD 800000017a07a067 P4D 800000017a07a067 PUD 1255f4067 PMD 0
[38913.266045] Oops: 0002 [#1] SMP PTI
[38913.266048] Modules linked in: allocmemory(OE) vfat fat uas usb_storage nf_nat_h323 nf_conntrack_h323 nf_nat_pptp nf_nat_proto_gre nf_conntrack_pptp nf_conntrack_proto_gre nf_nat_tftp nf_conntrack_tftp nf_nat_sip nf_conntrack_sip nf_nat_irc nf_conntrack_irc nf_nat_ftp nf_conntrack_ftp bnep fuse ccm xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun nf_conntrack_netbios_ns nf_conntrack_broadcast xt_CT ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack libcrc32c iptable_mangle iptable_raw iptable_security ebtable_filter ebtables ip6table_filter ip6_tables
[38913.266113] sunrpc uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core snd_hda_codec_hdmi intel_rapl intel_soc_dts_thermal intel_soc_dts_iosf intel_powerclamp coretemp kvm_intel arc4 videodev snd_hda_codec_realtek rt2800pci kvm rt2800mmio rt2800lib rt2x00pci irqbypass snd_hda_codec_generic rt2x00mmio media rt2x00lib wmi_bmof iTCO_wdt hp_wmi iTCO_vendor_support snd_hda_intel crct10dif_pclmul crc32_pclmul snd_hda_codec snd_intel_sst_acpi snd_intel_sst_core snd_soc_sst_atom_hifi2_platform ghash_clmulni_intel mac80211 cfg80211 snd_soc_sst_match hci_uart intel_cstate snd_soc_core rtsx_pci_ms btbcm btqca snd_compress memstick eeprom_93cx6 snd_pcm_dmaengine ac97_bus snd_hda_core snd_hwdep btintel bluetooth snd_seq snd_seq_device joydev snd_pcm snd_timer wmi ecdh_generic hp_accel rfkill_gpio
[38913.266182] lis3lv02d input_polldev dw_dmac snd soundcore intel_vbtn sparse_keymap lpc_ich intel_int0002_vgpio rfkill spi_pxa2xx_platform shpchp mei_txe hp_wireless mei i2c_i801 binfmt_misc i915 rtsx_pci_sdmmc i2c_algo_bit crc32c_intel drm_kms_helper drm serio_raw r8169 rtsx_pci mii sdhci_acpi video sdhci mmc_core i2c_hid pwm_lpss_platform pwm_lpss [last unloaded: allocmemory]

kartik.gupta

This bug means --> trying to dereference the NULL location.

At some point in your code , there is an attempt made to access the contents of NULL pointer.

for eg.

struct Qset *sqset=NULL;

if we will do sqset->next ,then kernel will throw the error as it can't handle the NULL location contents.

Carecter Device Driver

Howdy, Stranger!

Categories