While booting i386 with Linux next 20200908 tag kernel this warning noticed.
metadata:
git branch: master
git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
git commit: dff9f829e5b0181d4ed9d35aa62d695292399b54
git describe: next-20200908
kernel-config:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/853/config
warning log:
-----------------
[ 11.451223] Write protecting kernel text and read-only data: 20800k
[ 11.457522] Run /sbin/init as init process
[ 11.463807] random: fast init done
[ 11.471527]
[ 11.473118] =============================
[ 11.477129] WARNING: suspicious RCU usage
[ 11.481135] 5.9.0-rc4-next-20200908 #1 Not tainted
[ 11.485926] -----------------------------
[ 11.489931] /usr/src/kernel/include/trace/events/tlb.h:57
suspicious rcu_dereference_check() usage!
[ 11.498970]
[ 11.498970] other info that might help us debug this:
[ 11.498970]
[ 11.506961]
[ 11.506961] rcu_scheduler_active = 2, debug_locks = 1
[ 11.513476] RCU used illegally from extended quiescent state!
[ 11.519215] no locks held by swapper/0/0.
[ 11.523217]
[ 11.523217] stack backtrace:
[ 11.527569] CPU: 0 PID: 0 Comm: swapper/0 Not tainted
5.9.0-rc4-next-20200908 #1
[ 11.534955] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.2 05/23/2018
[ 11.542345] Call Trace:
[ 11.544792] dump_stack+0x6d/0x8b
[ 11.548112] lockdep_rcu_suspicious+0xb2/0xd0
[ 11.552473] switch_mm_irqs_off+0x508/0x510
[ 11.556658] switch_mm+0x19/0x50
[ 11.559890] leave_mm+0x2d/0x40
[ 11.563034] acpi_idle_enter_bm+0x1c/0x120
[ 11.567127] acpi_idle_enter+0x13b/0x230
[ 11.571049] ? rcu_eqs_enter.constprop.87+0x9e/0x180
[ 11.576008] ? acpi_idle_enter_s2idle+0x50/0x50
[ 11.580542] cpuidle_enter_state+0x87/0x560
[ 11.584732] cpuidle_enter+0x27/0x40
[ 11.588316] do_idle+0x20b/0x2a0
[ 11.591551] cpu_startup_entry+0x25/0x30
[ 11.595474] rest_init+0x166/0x230
[ 11.598881] arch_call_rest_init+0xd/0x19
[ 11.602893] start_kernel+0x481/0x4a0
[ 11.606562] i386_start_kernel+0x48/0x4a
[ 11.610485] startup_32_smp+0x164/0x168
[ 11.614338]
[ 11.614339] =============================
[ 11.614339] WARNING: suspicious RCU usage
[ 11.614340] 5.9.0-rc4-next-20200908 #1 Not tainted
[ 11.614340] -----------------------------
[ 11.614341] /usr/src/kernel/include/trace/events/lock.h:37
suspicious rcu_dereference_check() usage!
[ 11.614341]
[ 11.614341] other info that might help us debug this:
[ 11.614342]
[ 11.614342]
[ 11.614342] rcu_scheduler_active = 2, debug_locks = 1
[ 11.614343] RCU used illegally from extended quiescent state!
[ 11.614343] no locks held by swapper/0/0.
[ 11.614343]
[ 11.614344] stack backtrace:
[ 11.614344] CPU: 0 PID: 0 Comm: swapper/0 Not tainted
5.9.0-rc4-next-20200908 #1
[ 11.614345] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.2 05/23/2018
[ 11.614345] Call Trace:
[ 11.614345] dump_stack+0x6d/0x8b
[ 11.614346] lockdep_rcu_suspicious+0xb2/0xd0
[ 11.614346] lock_acquire+0x2d8/0x340
[ 11.614346] _raw_spin_lock+0x27/0x40
[ 11.614347] ? vprintk_emit+0x57/0x2c0
[ 11.614347] vprintk_emit+0x57/0x2c0
[ 11.614347] vprintk_default+0x17/0x20
[ 11.614348] vprintk_func+0x4f/0xd0
[ 11.614348] printk+0x13/0x15
[ 11.614348] lockdep_rcu_suspicious+0x21/0xd0
[ 11.614349] switch_mm_irqs_off+0x508/0x510
[ 11.614349] switch_mm+0x19/0x50
[ 11.614349] leave_mm+0x2d/0x40
[ 11.614350] acpi_idle_enter_bm+0x1c/0x120
[ 11.614350] acpi_idle_enter+0x13b/0x230
[ 11.614351] ? rcu_eqs_enter.constprop.87+0x9e/0x180
[ 11.614351] ? acpi_idle_enter_s2idle+0x50/0x50
[ 11.614351] cpuidle_enter_state+0x87/0x560
[ 11.614352] cpuidle_enter+0x27/0x40
[ 11.614352] do_idle+0x20b/0x2a0
[ 11.614352] cpu_startup_entry+0x25/0x30
[ 11.614353] rest_init+0x166/0x230
[ 11.614353] arch_call_rest_init+0xd/0x19
[ 11.614353] start_kernel+0x481/0x4a0
[ 11.614354] i386_start_kernel+0x48/0x4a
[ 11.614354] startup_32_smp+0x164/0x168
[ 11.614354]
[ 11.614355] =============================
[ 11.614355] WARNING: suspicious RCU usage
[ 11.614356] 5.9.0-rc4-next-20200908 #1 Not tainted
[ 11.614356] -----------------------------
[ 11.614356] /usr/src/kernel/include/trace/events/lock.h:63
suspicious rcu_dereference_check() usage!
[ 11.614357]
[ 11.614357] other info that might help us debug this:
[ 11.614357]
[ 11.614358]
[ 11.614358] rcu_scheduler_active = 2, debug_locks = 1
[ 11.614358] RCU used illegally from extended quiescent state!
[ 11.614359] 1 lock held by swapper/0/0:
[ 11.614359] #0: c82fd670 (logbuf_lock){-...}-{2:2}, at:
vprintk_emit+0x57/0x2c0
[ 11.614361]
[ 11.614361] stack backtrace:
[ 11.614362] CPU: 0 PID: 0 Comm: swapper/0 Not tainted
5.9.0-rc4-next-20200908 #1
[ 11.614362] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.2 05/23/2018
[ 11.614362] Call Trace:
[ 11.614363] dump_stack+0x6d/0x8b
[ 11.614363] lockdep_rcu_suspicious+0xb2/0xd0
[ 11.614364] lock_release+0x23c/0x260
[ 11.614364] ? vprintk_emit+0x79/0x2c0
[ 11.614364] _raw_spin_unlock+0x16/0x30
[ 11.614365] vprintk_emit+0x79/0x2c0
[ 11.614365] vprintk_default+0x17/0x20
[ 11.614365] vprintk_func+0x4f/0xd0
[ 11.614366] printk+0x13/0x15
[ 11.614366] lockdep_rcu_suspicious+0x21/0xd0
[ 11.614366] switch_mm_irqs_off+0x508/0x510
[ 11.614367] switch_mm+0x19/0x50
[ 11.614367] leave_mm+0x2d/0x40
[ 11.614367] acpi_idle_enter_bm+0x1c/0x120
[ 11.614368] acpi_idle_enter+0x13b/0x230
[ 11.614368] ? rcu_eqs_enter.constprop.87+0x9e/0x180
[ 11.614368] ? acpi_idle_enter_s2idle+0x50/0x50
[ 11.614369] cpuidle_enter_state+0x87/0x560
[ 11.614369] cpuidle_enter+0x27/0x40
[ 11.614369] do_idle+0x20b/0x2a0
[ 11.614370] cpu_startup_entry+0x25/0x30
[ 11.614370] rest_init+0x166/0x230
[ 11.614370] arch_call_rest_init+0xd/0x19
[ 11.614371] start_kernel+0x481/0x4a0
[ 11.614371] i386_start_kernel+0x48/0x4a
[ 11.614371] startup_32_smp+0x164/0x168
Full test log,
https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20200908/testrun/3171106/suite/linux-log-parser/test/check-kernel-warning-1743529/log
--
Linaro LKFT
https://lkft.linaro.org