FYI, we noticed the following commit: commit: ea0639c4d5c700ad63c0ace6a7a17877aac5b4c2 ("printk.c: removed unnecessary code") url: https://github.com/0day-ci/linux/commits/Sebastian-Duda/printk-c-removed-... in testcase: trinity 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-i386 -enable-kvm -m 256M caused below changes: +-------------------------------------------------------+------------+------------+ | | ded6e842cf | ea0639c4d5 | +-------------------------------------------------------+------------+------------+ | boot_successes | 19 | 8 | | boot_failures | 3 | 49 | | invoked_oom-killer:gfp_mask=0x | 1 | | | Mem-Info | 1 | | | IP-Config:Auto-configuration_of_network_failed | 2 | | | BUG:recent_printk_recursion | 0 | 47 | | BUG_kmalloc-#(Tainted:G_S):Redzone_overwritten | 0 | 11 | | INFO:#-#.First_byte#instead_of | 0 | 11 | | INFO:Allocated_in#age=#cpu=#pid= | 0 | 11 | | INFO:Freed_in#age=#cpu=#pid= | 0 | 11 | | INFO:Slab#objects=#used=#fp=#flags= | 0 | 11 | | INFO:Object#@offset=#fp= | 0 | 11 | | calltrace:SyS_read | 0 | 11 | | BUG_kmalloc-#(Tainted:G_S_B):Redzone_overwritten | 0 | 6 | | INFO:Allocated_in_do_syslog_age=#cpu=#pid= | 0 | 4 | | INFO:Freed_in_do_syslog_age=#cpu=#pid= | 0 | 5 | | INFO:Slab#objects=#used=#fp=0x(null)flags= | 0 | 6 | | BUG:unable_to_handle_kernel | 0 | 5 | | Oops | 0 | 5 | | EIP_is_at__slab_free | 0 | 3 | | calltrace:SyS_socketcall | 0 | 2 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 4 | | INFO:Allocated_in_pskb_expand_head_age=#cpu=#pid= | 0 | 1 | | INFO:Freed_in_skb_free_head_age=#cpu=#pid= | 0 | 1 | | calltrace:SyS_perf_event_open | 0 | 3 | | calltrace:rcu_do_batch | 0 | 1 | | calltrace:smpboot_thread_fn | 0 | 1 | | Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 0 | 1 | | INFO:Allocated_in_sk_prot_alloc_age=#cpu=#pid= | 0 | 1 | | INFO:Freed_in__sk_destruct_age=#cpu=#pid= | 0 | 1 | | INFO:Allocated_in_alloc_fdmem_age=#cpu=#pid= | 0 | 1 | | INFO:Object#@offset=#fp=0x(null) | 0 | 1 | | EIP_is_at_vlan_device_event | 0 | 2 | | calltrace:vlan_device_event | 0 | 2 | | calltrace:SyS_ioctl | 0 | 2 | +-------------------------------------------------------+------------+------------+ [ 41.024699] --dropprivs is still in development, and really shouldn't be used unless you're helping development. Expect crashes. [ 41.024699] Going to run as user nobody (uid:1 gid:1) [ 41.024699] ctrl-c now unless you really know what you are doing. [ 42.078282] BUG: recent printk recursion! [ 42.276131] e1000: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX [ 42.384840] 8021q: adding VLAN 0 to HW filter on device eth0 [ 44.409493] e1000: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX To reproduce: git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git cd lkp-tests bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email Thanks, Xiaolong