FYI, we noticed the following commit (built with gcc-7): commit: cd8f62b481530fafbeacee0d3283b60bcf42d854 ("[PATCH 02/12 v2] tracing: Save off entry when peeking at next entry") url: https://github.com/0day-ci/linux/commits/Steven-Rostedt/ring-buffer-tracing-Remove-disabling-of-ring-buffer-while-reading-trace-file/20200320-073240 in testcase: rcuperf with following parameters: runtime: 300s perf_type: rcu on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 8G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +----------------------------------------------------------------+------------+------------+ | | 2e2bf17ca0 | cd8f62b481 | +----------------------------------------------------------------+------------+------------+ | boot_successes | 13 | 0 | | boot_failures | 0 | 8 | | BUG:sleeping_function_called_from_invalid_context_at_mm/slab.h | 0 | 8 | +----------------------------------------------------------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot [ 16.821280] BUG: sleeping function called from invalid context at mm/slab.h:565 [ 16.822211] in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 158, name: rcu_perf_writer [ 16.823164] no locks held by rcu_perf_writer/158. [ 16.823650] CPU: 0 PID: 158 Comm: rcu_perf_writer Not tainted 5.6.0-rc6-00081-gcd8f62b481530f #1 [ 16.824856] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 [ 16.826220] Call Trace: [ 16.826667] dump_stack+0x16/0x18 [ 16.827265] ___might_sleep+0x104/0x118 [ 16.827947] __might_sleep+0x69/0x70 [ 16.828600] ? __fs_reclaim_release+0x17/0x19 [ 16.829374] slab_pre_alloc_hook+0x34/0x6e [ 16.830107] __kmalloc+0x48/0xe8 [ 16.830710] ? rb_reader_unlock+0x2b/0x3c [ 16.831205] ? trace_find_next_entry+0x84/0x133 [ 16.831723] trace_find_next_entry+0x84/0x133 [ 16.832217] trace_print_lat_context+0x4b/0x437 [ 16.832730] ? rb_event_length+0x56/0x67 [ 16.833186] ? ring_buffer_event_length+0x34/0x79 [ 16.833728] ? __find_next_entry+0xd3/0x1c2 [ 16.834190] print_trace_line+0x69d/0x767 [ 16.834666] ftrace_dump+0x285/0x437 [ 16.835055] rcu_perf_writer+0x25f/0x34e [ 16.835476] kthread+0xdf/0xe1 [ 16.835823] ? rcu_perf_reader+0x9c/0x9c [ 16.836264] ? kthread_create_worker_on_cpu+0x1c/0x1c [ 16.836834] ret_from_fork+0x2e/0x38 [ 16.837270] rb_produ-160 0.... 6528532us : ring_buffer_producer: Starting ring buffer hammer [ 16.838318] rb_produ-160 0.... 16529141us : ring_buffer_producer: End ring buffer hammer [ 16.839349] rb_produ-160 0.... 16558157us : ring_buffer_producer: Running Consumer at nice: 19 [ 16.840382] rb_produ-160 0.... 16558162us : ring_buffer_producer: Running Producer at nice: 19 [ 16.841401] rb_produ-160 0.... 16558163us : ring_buffer_producer: WARNING!!! This test is running at lowest priority. [ 16.854781] rb_produ-160 0.... 16558164us : ring_buffer_producer: Time: 10000604 (usecs) [ 16.857354] rb_produ-160 0.... 16558165us : ring_buffer_producer: Overruns: 6117960 [ 16.858322] rb_produ-160 0.... 16558166us : ring_buffer_producer: Read: 4356190 (by events) [ 16.859404] rb_produ-160 0.... 16558167us : ring_buffer_producer: Entries: 44650 [ 16.860329] rb_produ-160 0.... 16558167us : ring_buffer_producer: Total: 10518800 [ 16.861226] rb_produ-160 0.... 16558168us : ring_buffer_producer: Missed: 0 [ 16.862124] rb_produ-160 0.... 16558169us : ring_buffer_producer: Hit: 10518800 [ 16.863087] rb_produ-160 0.... 16558170us : ring_buffer_producer: Entries per millisec: 1051 [ 16.864123] rb_produ-160 0.... 16558171us : ring_buffer_producer: 951 ns per entry [ 16.865074] rb_produ-160 0.... 16558172us : ring_buffer_producer_thread: Sleeping for 10 secs [ 16.866105] --------------------------------- [ 16.866725] rcu-perf: Test complete [ 16.878198] random: fast init done Elapsed time: 60 qemu-img create -f qcow2 disk-vm-snb-i386-9-0 256G qemu-img create -f qcow2 disk-vm-snb-i386-9-1 256G qemu-img create -f qcow2 disk-vm-snb-i386-9-2 256G qemu-img create -f qcow2 disk-vm-snb-i386-9-3 256G qemu-img create -f qcow2 disk-vm-snb-i386-9-4 256G qemu-img create -f qcow2 disk-vm-snb-i386-9-5 256G qemu-img create -f qcow2 disk-vm-snb-i386-9-6 256G kvm=( qemu-system-i386 -enable-kvm -cpu SandyBridge -kernel $kernel -initrd initrd-vm-snb-i386-9.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 -drive file=disk-vm-snb-i386-9-0,media=disk,if=virtio -drive file=disk-vm-snb-i386-9-1,media=disk,if=virtio -drive file=disk-vm-snb-i386-9-2,media=disk,if=virtio -drive file=disk-vm-snb-i386-9-3,media=disk,if=virtio -drive file=disk-vm-snb-i386-9-4,media=disk,if=virtio -drive file=disk-vm-snb-i386-9-5,media=disk,if=virtio -drive file=disk-vm-snb-i386-9-6,media=disk,if=virtio -serial stdio -display none -monitor null ) append=( ip=::::vm-snb-i386-9::dhcp root=/dev/ram0 user=lkp job=/job-script ARCH=i386 kconfig=i386-randconfig-g003-20200324 branch=linux-devel/devel-hourly-2020032505 commit=cd8f62b481530fafbeacee0d3283b60bcf42d854 BOOT_IMAGE=/pkg/linux/i386-randconfig-g003-20200324/gcc-7/cd8f62b481530fafbeacee0d3283b60bcf42d854/vmlinuz-5.6.0-rc6-00081-gcd8f62b481530f max_uptime=1500 RESULT_ROOT=/result/rcuperf/rcu-300s/vm-snb-i386/yocto-i386-minimal-20190520.cgz/i386-randconfig-g003-20200324/gcc-7/cd8f62b481530fafbeacee0d3283b60bcf42d854/3 result_service=tmpfs selinux=0 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 To reproduce: # build kernel cd linux cp config-5.6.0-rc6-00081-gcd8f62b481530f .config make HOSTCC=gcc-7 CC=gcc-7 ARCH=i386 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, Rong Chen