I cannot reproduce this. I compiled the reproducer program and tested on a Eoan VM running in KVM, with the same 5.3.0-29-generic kernel:
ubuntu@ubuntu:~$ ./socktest Segmentation fault (core dumped) ubuntu@ubuntu:~$ tail /var/log/kern.log Feb 14 04:00:41 ubuntu kernel: [ 134.951620] socktest[1598]: segfault at 21 ip 000055892e4cb2a3 sp 00007ffed8905de0 error 6 in socktest[55892e4cb000+1000] Feb 14 04:00:41 ubuntu kernel: [ 134.951634] Code: 48 8d 4d e0 8b 45 dc ba 10 00 00 00 48 89 ce 89 c7 e8 71 fe ff ff 8b 45 dc be 0a 00 00 00 89 c7 e8 52 fe ff ff b8 21 00 00 00 <c7> 00 21 00 00 00 b8 00 00 00 00 48 8b 4d f8 64 48 33 0c 25 28 00 ubuntu@ubuntu:~$ ps ax | grep socktest 1602 pts/0 S+ 0:00 grep --color=auto socktest ubuntu@ubuntu:~$ uname -rv 5.3.0-29-generic #31-Ubuntu SMP Fri Jan 17 17:27:26 UTC 2020 The segfault happens as expected, but there is no null pointer dereference and no stack trace in dmesg. The process is terminated and I can still bind to port 6000 with netcat. I see that you have Virtual Box kernel modules loaded. Can you try reproduce this on a fresh Eoan VM with no Virtual Box drivers installed? -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1863086 Title: unkillable process (kernel NULL pointer dereference) Status in linux package in Ubuntu: Confirmed Bug description: If process that listens socket on any port crashes (segmentation fault) it becomes unkillable. Kill command does not kill this process. Port that listen crashed process never be freed. journalctl shows error: Feb 13 13:28:09 vbun04 kernel: socktest[1359]: segfault at 21 ip 000055ec3a6bf11e sp 00007ffd88899fb0 error 6 in socktest[55ec3a6bf000+1000] Feb 13 13:28:09 vbun04 kernel: Code: 04 24 02 00 17 70 89 c5 48 b8 30 30 30 30 30 30 30 30 89 ef 48 89 44 24 08 e8 8e ff ff ff be 0a 00 00 00 89 ef e8 72 ff ff ff <c7> 04 25 21 00 00 00 21 00 00 00 48 8b 44 24 18 Feb 13 13:28:09 vbun04 kernel: BUG: kernel NULL pointer dereference, address: 0000000000000020 Feb 13 13:28:09 vbun04 kernel: #PF: supervisor read access in kernel mode Feb 13 13:28:09 vbun04 kernel: #PF: error_code(0x0000) - not-present page Feb 13 13:28:09 vbun04 kernel: PGD 0 P4D 0 Feb 13 13:28:09 vbun04 kernel: Oops: 0000 [#1] SMP NOPTI Feb 13 13:28:09 vbun04 kernel: CPU: 1 PID: 1359 Comm: socktest Tainted: G OE 5.3.0-29-generic #31-Ubuntu Feb 13 13:28:09 vbun04 kernel: Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 Feb 13 13:28:09 vbun04 kernel: RIP: 0010:do_coredump+0x536/0xb30 Feb 13 13:28:09 vbun04 kernel: Code: 00 48 8b bd 18 ff ff ff 48 85 ff 74 05 e8 c2 47 fa ff 65 48 8b 04 25 c0 6b 01 00 48 8b 00 48 8b 7d a0 a8 04 0f 85 65 05 00 00 <48> 8b 57 20 0f b7 02 66 25 00 f0 66 3d 00 80 0f Feb 13 13:28:09 vbun04 kernel: RSP: 0000:ffffb464c2c5fca8 EFLAGS: 00010246 Feb 13 13:28:09 vbun04 kernel: RAX: 0000000000000000 RBX: ffff9d4b76995100 RCX: 0000000000001afc Feb 13 13:28:09 vbun04 kernel: RDX: 0000000000000000 RSI: ffffb464c2c5fc68 RDI: 0000000000000000 Feb 13 13:28:09 vbun04 kernel: RBP: ffffb464c2c5fdd8 R08: 0000000000000400 R09: ffffb464c2c5fbe0 Feb 13 13:28:09 vbun04 kernel: R10: ffff9d4b75d01170 R11: 0000000000000000 R12: ffff9d4b7b3df540 Feb 13 13:28:09 vbun04 kernel: R13: 0000000000000001 R14: 0000000000000000 R15: ffffffffb9f15920 Feb 13 13:28:09 vbun04 kernel: FS: 00007f6c91911540(0000) GS:ffff9d4b7db00000(0000) knlGS:0000000000000000 Feb 13 13:28:09 vbun04 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Feb 13 13:28:09 vbun04 kernel: CR2: 0000000000000020 CR3: 00000000723ac003 CR4: 00000000000606e0 Feb 13 13:28:09 vbun04 kernel: Call Trace: Feb 13 13:28:09 vbun04 kernel: ? wake_up_state+0x10/0x20 Feb 13 13:28:09 vbun04 kernel: ? __send_signal+0x1eb/0x3f0 Feb 13 13:28:09 vbun04 kernel: get_signal+0x159/0x880 Feb 13 13:28:09 vbun04 kernel: do_signal+0x34/0x280 Feb 13 13:28:09 vbun04 kernel: ? bad_area+0x47/0x50 Feb 13 13:28:09 vbun04 kernel: exit_to_usermode_loop+0xbf/0x160 Feb 13 13:28:09 vbun04 kernel: prepare_exit_to_usermode+0x77/0xa0 Feb 13 13:28:09 vbun04 kernel: retint_user+0x8/0x8 Feb 13 13:28:09 vbun04 kernel: RIP: 0033:0x55ec3a6bf11e Feb 13 13:28:09 vbun04 kernel: Code: 04 24 02 00 17 70 89 c5 48 b8 30 30 30 30 30 30 30 30 89 ef 48 89 44 24 08 e8 8e ff ff ff be 0a 00 00 00 89 ef e8 72 ff ff ff <c7> 04 25 21 00 00 00 21 00 00 00 48 8b 44 24 18 Feb 13 13:28:09 vbun04 kernel: RSP: 002b:00007ffd88899fb0 EFLAGS: 00010217 Feb 13 13:28:09 vbun04 kernel: RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6c918424eb Feb 13 13:28:09 vbun04 kernel: RDX: 0000000000000010 RSI: 000000000000000a RDI: 0000000000000003 Feb 13 13:28:09 vbun04 kernel: RBP: 0000000000000003 R08: 0000000000000000 R09: 00007f6c919331f0 Feb 13 13:28:09 vbun04 kernel: R10: 0000000000000000 R11: 0000000000000217 R12: 000055ec3a6bf150 Feb 13 13:28:09 vbun04 kernel: R13: 00007ffd8889a0b0 R14: 0000000000000000 R15: 0000000000000000 Feb 13 13:28:09 vbun04 kernel: Modules linked in: vboxsf(OE) nls_utf8 isofs vboxvideo(OE) intel_rapl_msr intel_rapl_common crct10dif_pclmul vmwgfx crc32_pclmul ghash_clmulni_intel aesni_intel ttm drm_kms_helper a Feb 13 13:28:09 vbun04 kernel: CR2: 0000000000000020 Feb 13 13:28:09 vbun04 kernel: ---[ end trace 278d665c8727286a ]--- Feb 13 13:28:09 vbun04 kernel: RIP: 0010:do_coredump+0x536/0xb30 Feb 13 13:28:09 vbun04 kernel: Code: 00 48 8b bd 18 ff ff ff 48 85 ff 74 05 e8 c2 47 fa ff 65 48 8b 04 25 c0 6b 01 00 48 8b 00 48 8b 7d a0 a8 04 0f 85 65 05 00 00 <48> 8b 57 20 0f b7 02 66 25 00 f0 66 3d 00 80 0f Feb 13 13:28:09 vbun04 kernel: RSP: 0000:ffffb464c2c5fca8 EFLAGS: 00010246 Feb 13 13:28:09 vbun04 kernel: RAX: 0000000000000000 RBX: ffff9d4b76995100 RCX: 0000000000001afc Feb 13 13:28:09 vbun04 kernel: RDX: 0000000000000000 RSI: ffffb464c2c5fc68 RDI: 0000000000000000 Feb 13 13:28:09 vbun04 kernel: RBP: ffffb464c2c5fdd8 R08: 0000000000000400 R09: ffffb464c2c5fbe0 Feb 13 13:28:09 vbun04 kernel: R10: ffff9d4b75d01170 R11: 0000000000000000 R12: ffff9d4b7b3df540 Feb 13 13:28:09 vbun04 kernel: R13: 0000000000000001 R14: 0000000000000000 R15: ffffffffb9f15920 Feb 13 13:28:09 vbun04 kernel: FS: 00007f6c91911540(0000) GS:ffff9d4b7db00000(0000) knlGS:0000000000000000 Feb 13 13:28:09 vbun04 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Feb 13 13:28:09 vbun04 kernel: CR2: 0000000000000020 CR3: 00000000723ac003 CR4: 00000000000606e0 Steps to Reproduce: Compile and run following code: #include <sys/socket.h> #include <netinet/in.h> #include <string.h> int main() { int listenfd = 0; struct sockaddr_in serv_addr; listenfd = socket(AF_INET, SOCK_STREAM, 0); memset(&serv_addr, '0', sizeof(serv_addr)); serv_addr.sin_family = AF_INET; serv_addr.sin_addr.s_addr = htonl(INADDR_ANY); serv_addr.sin_port = htons(6000); bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)); listen(listenfd, 10); *(int*)33 = 33; return 0; } Process segfaulted and becomes unkillable, opened socket ports busy. ProblemType: Bug DistroRelease: Ubuntu 19.10 Package: linux-image-generic 5.3.0.29.33 ProcVersionSignature: Ubuntu 5.3.0-29.31-generic 5.3.13 Uname: Linux 5.3.0-29-generic x86_64 AlsaDevices: total 0 crw-rw----+ 1 root audio 116, 1 фев 13 13:24 seq crw-rw----+ 1 root audio 116, 33 фев 13 13:24 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay': 'aplay' ApportVersion: 2.20.11-0ubuntu8.2 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord': 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: CurrentDesktop: KDE Date: Thu Feb 13 13:49:19 2020 IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig': 'iwconfig' Lsusb: Error: [Errno 2] No such file or directory: 'lsusb': 'lsusb' MachineType: innotek GmbH VirtualBox PciMultimedia: ProcFB: 0 svgadrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.3.0-29-generic root=UUID=cd3a004e-4e27-4c93-8ae6-e1942680f565 ro mitigations=off ipv6.disable=1 net.ifnames=0 video=1280x960 RelatedPackageVersions: linux-restricted-modules-5.3.0-29-generic N/A linux-backports-modules-5.3.0-29-generic N/A linux-firmware 1.183.3 RfKill: Error: [Errno 2] No such file or directory: 'rfkill': 'rfkill' SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) WifiSyslog: dmi.bios.date: 12/01/2006 dmi.bios.vendor: innotek GmbH dmi.bios.version: VirtualBox dmi.board.name: VirtualBox dmi.board.vendor: Oracle Corporation dmi.board.version: 1.2 dmi.chassis.type: 1 dmi.chassis.vendor: Oracle Corporation dmi.modalias: dmi:bvninnotekGmbH:bvrVirtualBox:bd12/01/2006:svninnotekGmbH:pnVirtualBox:pvr1.2:rvnOracleCorporation:rnVirtualBox:rvr1.2:cvnOracleCorporation:ct1:cvr: dmi.product.family: Virtual Machine dmi.product.name: VirtualBox dmi.product.version: 1.2 dmi.sys.vendor: innotek GmbH To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1863086/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
