Greeting, FYI, we noticed the following commit (built with gcc-9): commit: a76eadba0db10b76d2e966059f25d01993e3e1a1 ("[RFC PATCH v2] Softirq:avoid large sched delay from the pending softirqs") url: https://github.com/0day-ci/linux/commits/qianjun-kernel-gmail-com/Softirq-avoid-large-sched-delay-from-the-pending-softirqs/20200720-211120 base: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git 5714ee50bb4375bd586858ad800b1d9772847452 in testcase: hwsim with following parameters: group: hwsim-28 on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 8 -m 16G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +----------------------------------------------------------------------------+------------+------------+ | | 5714ee50bb | a76eadba0d | +----------------------------------------------------------------------------+------------+------------+ | boot_successes | 11 | 9 | | boot_failures | 1 | 18 | | BUG:kernel_hang_in_boot_stage | 1 | | | Kernel_panic-not_syncing:VFS:Unable_to_mount_root_fs_on_unknown-block(#,#) | 0 | 2 | | WARNING:at_net/mac80211/rx.c:#ieee80211_rx_napi[mac80211] | 0 | 16 | | RIP:ieee80211_rx_napi[mac80211] | 0 | 16 | | INFO:rcu_sched_self-detected_stall_on_CPU | 0 | 6 | | RIP:console_unlock | 0 | 6 | | INFO:rcu_sched_detected_stalls_on_CPUs/tasks | 0 | 6 | | RIP:x2apic_send_IPI | 0 | 5 | | RIP:vprintk_emit | 0 | 5 | | RIP:default_idle | 0 | 3 | | RIP:io_serial_in | 0 | 1 | +----------------------------------------------------------------------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot [ 106.856151] WARNING: CPU: 5 PID: 4569 at net/mac80211/rx.c:4708 ieee80211_rx_napi+0x44d/0x560 [mac80211] [ 106.858369] Modules linked in: ccm mac80211_hwsim mac80211 cfg80211 rfkill libarc4 sr_mod cdrom sg ata_generic bochs_drm intel_rapl_msr drm_vram_helper ipmi_devintf drm_ttm_helper intel_rapl_common ttm ipmi_msghandler crct10dif_pclmul drm_kms_helper crc32_pclmul crc32c_intel ghash_clmulni_intel syscopyarea sysfillrect sysimgblt fb_sys_fops ppdev ata_piix parport_pc drm joydev parport serio_raw libata i2c_piix4 ip_tables [ 106.873183] CPU: 5 PID: 4569 Comm: hostapd Not tainted 5.8.0-rc6-00002-ga76eadba0db10 #1 [ 106.879825] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 [ 106.883913] RIP: 0010:ieee80211_rx_napi+0x44d/0x560 [mac80211] [ 106.887468] Code: 45 44 24 04 89 44 24 04 e9 6d fd ff ff 0f 0b e9 72 fe ff ff 0f b6 45 4a 83 e8 01 3c 07 0f 87 97 fe ff ff 31 d2 e9 7a fc ff ff <0f> 0b e9 55 fe ff ff 4c 89 e7 e8 84 ff 0d cf 48 85 c0 0f 84 14 fe [ 106.894436] RSP: 0018:ffffb0d280188e90 EFLAGS: 00010246 [ 106.899763] RAX: 0000000000000000 RBX: ffff90c0e39847e0 RCX: 0000000000000000 [ 106.903868] RDX: ffff90c0e3985ec8 RSI: 0000000000000000 RDI: ffff90c0e39847e0 [ 106.906345] RBP: ffff90c0e392e500 R08: 0000000000000000 R09: ffffffffc0873000 [ 106.911449] R10: ffff90c0e392fd00 R11: 0000000000000001 R12: ffff90c0e392e500 [ 106.913620] R13: 0000000000000000 R14: 0000000000000040 R15: ffffffff906050e0 [ 106.920097] FS: 00007ffbb8a4eb80(0000) GS:ffff90c17fd40000(0000) knlGS:0000000000000000 [ 106.922530] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 106.924537] CR2: 00007fdb4bae4d50 CR3: 00000003a393c000 CR4: 00000000000406e0 [ 106.926725] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 106.928974] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 106.941826] Call Trace: [ 106.943761] [ 106.945475] ? ieee80211_tx_status+0x71/0xa0 [mac80211] [ 106.961847] ? kmem_cache_free+0x212/0x280 [ 106.964038] ieee80211_tasklet_handler+0xbc/0xd0 [mac80211] [ 106.966220] tasklet_action_common+0x4f/0x100 [ 106.968344] __do_softirq+0xe7/0x32e [ 106.970246] asm_call_on_stack+0x12/0x20 [ 106.972192] [ 106.977831] do_softirq_own_stack+0x39/0x50 [ 106.979993] do_softirq+0x2b/0x30 [ 106.982020] __local_bh_enable_ip+0x4b/0x50 [ 106.984023] ieee80211_mgmt_tx+0x466/0x590 [mac80211] [ 106.986185] ? skb_partial_csum_set+0x60/0x80 [ 106.988239] cfg80211_mlme_mgmt_tx+0x108/0x310 [cfg80211] [ 107.005903] nl80211_tx_mgmt+0x292/0x3b0 [cfg80211] [ 107.008082] genl_rcv_msg+0x1a4/0x2fc [ 107.009886] ? genl_start+0x140/0x140 [ 107.011725] netlink_rcv_skb+0x49/0x110 [ 107.016692] genl_rcv+0x24/0x40 [ 107.018603] netlink_unicast+0x191/0x230 [ 107.020501] netlink_sendmsg+0x243/0x480 [ 107.022365] sock_sendmsg+0x5e/0x60 [ 107.032305] ____sys_sendmsg+0x1f3/0x260 [ 107.034175] ? copy_msghdr_from_user+0x5c/0x90 [ 107.039443] ___sys_sendmsg+0x81/0xc0 [ 107.041151] ? __generic_file_write_iter+0xf9/0x1d0 [ 107.042989] ? generic_file_write_iter+0x106/0x173 [ 107.044793] ? __cgroup_bpf_run_filter_setsockopt+0xb9/0x320 [ 107.046678] __sys_sendmsg+0x59/0xa0 [ 107.048170] do_syscall_64+0x4c/0x90 [ 107.049696] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 107.065381] RIP: 0033:0x7ffbb8b6d914 [ 107.068221] Code: Bad RIP value. [ 107.069764] RSP: 002b:00007ffcae5590c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 107.071892] RAX: ffffffffffffffda RBX: 000055dba32b81b0 RCX: 00007ffbb8b6d914 [ 107.073939] RDX: 0000000000000000 RSI: 00007ffcae559100 RDI: 0000000000000007 [ 107.079830] RBP: 000055dba32c3b20 R08: 0000000000000004 R09: 00007ffbb8c2f3a0 [ 107.081785] R10: 00007ffcae5591dc R11: 0000000000000246 R12: 000055dba32b80c0 [ 107.086149] R13: 00007ffcae559100 R14: 00007ffcae559238 R15: 00007ffcae5591dc [ 107.088023] ---[ end trace abbdb1b7b4425524 ]--- To reproduce: # build kernel cd linux cp config-5.8.0-rc6-00002-ga76eadba0db10 .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, lkp