Greeting, FYI, we noticed the following commit (built with gcc-9): commit: 0ac0c30c8ff725f0300cb52c2e63700dcb1dd7be ("Reimplement RLIMIT_MEMLOCK on top of ucounts") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git Alexey-Gladkov/Count-rlimits-in-each-user-namespace/20210201-222426 in testcase: trinity version: trinity-static-x86_64-x86_64-1c734c75-1_2020-01-06 with following parameters: runtime: 300s test-description: Trinity is a linux system call fuzz tester. test-url: http://codemonkey.org.uk/projects/trinity/ on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 8G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +------------------------------------------------+------------+------------+ | | 82b53805c5 | 0ac0c30c8f | +------------------------------------------------+------------+------------+ | Oops:#[##] | 4 | 3 | | RIP:is_ucounts_overlimit | 4 | 1 | | Kernel_panic-not_syncing:Fatal_exception | 4 | 3 | | RIP:inc_rlimit_ucounts_and_test | 0 | 3 | | WARNING:at_kernel/ucount.c:#dec_rlimit_ucounts | 0 | 1 | | RIP:dec_rlimit_ucounts | 0 | 1 | +------------------------------------------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot [ 31.706679] WARNING: CPU: 1 PID: 760 at kernel/ucount.c:291 dec_rlimit_ucounts (kbuild/src/consumer/kernel/ucount.c:291 (discriminator 1)) [ 31.707605] Modules linked in: mpls_router ip_tunnel af_key vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vsock vmw_vmci ieee802154_socket ieee802154 hidp bnep rfcomm bluetooth ecdh_generic ecc rfkill can_bcm can_raw can crypto_user nfnetlink scsi_transport_iscsi atm sctp ip6_udp_tunnel udp_tunnel libcrc32c sr_mod cdrom ata_generic ppdev bochs_drm drm_vram_helper drm_ttm_helper ttm drm_kms_helper intel_rapl_msr intel_rapl_common crct10dif_pclmul syscopyarea crc32_pclmul sysfillrect crc32c_intel sysimgblt fb_sys_fops ghash_clmulni_intel rapl drm ata_piix joydev serio_raw parport_pc parport i2c_piix4 libata [ 31.713767] CPU: 1 PID: 760 Comm: kworker/1:3 Not tainted 5.11.0-rc2-00008-g0ac0c30c8ff7 #1 [ 31.714811] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 [ 31.715844] Workqueue: events free_ipc [ 31.716626] RIP: 0010:dec_rlimit_ucounts (kbuild/src/consumer/kernel/ucount.c:291 (discriminator 1)) [ 31.717485] Code: 01 49 89 c0 48 89 c6 49 29 d0 f0 4c 0f b1 01 48 39 c6 75 ed 48 85 c0 78 11 48 8b 47 10 48 8b b8 e0 01 00 00 48 85 ff 75 d1 c3 <0f> 0b eb eb 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 2e 0f 1f 84 00 All code ======== 0: 01 49 89 add %ecx,-0x77(%rcx) 3: c0 48 89 c6 rorb $0xc6,-0x77(%rax) 7: 49 29 d0 sub %rdx,%r8 a: f0 4c 0f b1 01 lock cmpxchg %r8,(%rcx) f: 48 39 c6 cmp %rax,%rsi 12: 75 ed jne 0x1 14: 48 85 c0 test %rax,%rax 17: 78 11 js 0x2a 19: 48 8b 47 10 mov 0x10(%rdi),%rax 1d: 48 8b b8 e0 01 00 00 mov 0x1e0(%rax),%rdi 24: 48 85 ff test %rdi,%rdi 27: 75 d1 jne 0xfffffffffffffffa 29: c3 retq 2a:* 0f 0b ud2 <-- trapping instruction 2c: eb eb jmp 0x19 2e: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 35: 00 00 00 00 39: 66 data16 3a: 66 data16 3b: 2e cs 3c: 0f .byte 0xf 3d: 1f (bad) 3e: 84 00 test %al,(%rax) Code starting with the faulting instruction =========================================== 0: 0f 0b ud2 2: eb eb jmp 0xffffffffffffffef 4: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) b: 00 00 00 00 f: 66 data16 10: 66 data16 11: 2e cs 12: 0f .byte 0xf 13: 1f (bad) 14: 84 00 test %al,(%rax) [ 31.719705] RSP: 0018:ffffa61e002e7dd0 EFLAGS: 00010286 [ 31.720626] RAX: fffffffffffffe00 RBX: ffff89896b751800 RCX: ffff89894012da48 [ 31.721648] RDX: 00000000000a1c00 RSI: fffffffffffffe00 RDI: ffff89894012d9c0 [ 31.722688] RBP: ffff89896b799f00 R08: fffffffffff5e200 R09: 0000000000000088 [ 31.723717] R10: 0000000000000000 R11: ffff89896a6ab918 R12: ffff898969bd6400 [ 31.724743] R13: 0000000000000001 R14: ffff89896b799f00 R15: ffff89896b751800 [ 31.725757] FS: 0000000000000000(0000) GS:ffff898a77d00000(0000) knlGS:0000000000000000 [ 31.726743] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 31.727891] CR2: 00007f98a32e22fc CR3: 000000012e20c000 CR4: 00000000000406e0 [ 31.729080] DR0: 0000000000000000 DR1: 00007f98a1bd1000 DR2: 00007f98a22d1000 [ 31.729880] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 [ 31.730674] Call Trace: [ 31.731292] shm_destroy (kbuild/src/consumer/ipc/shm.c:293) [ 31.731936] free_ipcs (kbuild/src/consumer/ipc/namespace.c:106 (discriminator 2)) [ 31.732569] ? shm_destroy (kbuild/src/consumer/ipc/shm.c:114) [ 31.733224] shm_exit_ns (kbuild/src/consumer/ipc/shm.c:132) [ 31.733855] free_ipc (kbuild/src/consumer/ipc/namespace.c:29 (discriminator 6) kbuild/src/consumer/ipc/namespace.c:128 (discriminator 6) kbuild/src/consumer/ipc/namespace.c:141 (discriminator 6)) [ 31.734479] process_one_work (kbuild/src/consumer/arch/x86/include/asm/jump_label.h:25 kbuild/src/consumer/include/linux/jump_label.h:200 kbuild/src/consumer/include/trace/events/workqueue.h:108 kbuild/src/consumer/kernel/workqueue.c:2280) [ 31.735136] ? process_one_work (kbuild/src/consumer/kernel/workqueue.c:2364) [ 31.735777] worker_thread (kbuild/src/consumer/include/linux/list.h:282 kbuild/src/consumer/kernel/workqueue.c:2422) [ 31.736416] ? process_one_work (kbuild/src/consumer/kernel/workqueue.c:2364) [ 31.737065] kthread (kbuild/src/consumer/kernel/kthread.c:292) [ 31.737656] ? kthread_park (kbuild/src/consumer/kernel/kthread.c:245) [ 31.738275] ret_from_fork (kbuild/src/consumer/arch/x86/entry/entry_64.S:302) [ 31.738890] ---[ end trace 7a58348982bc0099 ]--- [ 306.675403] sh: can't kill pid 503: No such process [ 313.160211] sysrq: Emergency Sync [ 313.160911] sysrq: Resetting [ 313.1612 Kboot worker: lkp-worker60 Elapsed time: 360 kvm=( qemu-system-x86_64 -enable-kvm -cpu SandyBridge -kernel $kernel -initrd initrd-vm-snb-91.cgz -m 8192 -smp 2 -device e1000,netdev=net0 -netdev user,id=net0,hostfwd=tcp::32032-:22 -boot order=nc -no-reboot -watchdog i6300esb -watchdog-action debug -rtc base=localtime -serial stdio -display none -monitor null ) append=( ip=::::vm-snb-91::dhcp root=/dev/ram0 user=lkp job=/job-script ARCH=x86_64 kconfig=x86_64-rhel-8.3-kbuiltin branch=linux-devel/devel-catchup-20210202-110043 commit=0ac0c30c8ff725f0300cb52c2e63700dcb1dd7be BOOT_IMAGE=/pkg/linux/x86_64-rhel-8.3-kbuiltin/gcc-9/0ac0c30c8ff725f0300cb52c2e63700dcb1dd7be/vmlinuz-5.11.0-rc2-00008-g0ac0c30c8ff7 vmalloc=512M max_uptime=2100 RESULT_ROOT=/result/trinity/300s/vm-snb/yocto-x86_64-minimal-20190520.cgz/x86_64-rhel-8.3-kbuiltin/gcc-9/0ac0c30c8ff725f0300cb52c2e63700dcb1dd7be/0 result_service=tmpfs selinux=0 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 printk.devkmsg=on panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 drbd.minor_count=8 systemd.log_level=err ignore_loglevel console=tty0 earlyprintk=ttyS0,115200 console=ttyS0,115200 vga=normal rw rcuperf.shutdown=0 watchdog_thresh=240 ) "${kvm[@]}" -append "${append[*]}" To reproduce: # build kernel cd linux cp config-5.11.0-rc2-00008-g0ac0c30c8ff7 .config make HOSTCC=gcc-9 CC=gcc-9 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k job-script # job-script is attached in this email Thanks, Oliver Sang