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able to reproduce this splat on latest mainline with the attached > defconfig on QEMU, which I invoked as follows: > > $ qemu-system-mips64 -cpu I6400 -smp 2 -kernel vmlinux -nographic > > ============================= > WARNING: suspicious RCU usage > 7.0.0-rc7-dirty #13 Not tainted > ----------------------------- > kernel/locking/lockdep.c:3801 RCU-list traversed in non-reader section!! > > other info that might help us debug this: > > > RCU used illegally from offline CPU! > rcu_scheduler_active = 1, debug_locks = 1 > no locks held by swapper/1/0. > > stack backtrace: > CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 7.0.0-rc7-dirty #13 VOLUNTARY > Hardware name: mti,malta > Stack : a8000000021fb938 0000000000000000 0000000000000018 a8000000021fb888 > a8000000021fb888 a8000000021fb9b8 0000000000000000 0000000000000000 > 00f87412b0603bdf 0000000000000001 0000000000000000 0000000000000000 > ffffffff80f9e5b0 0000000000000000 ffffffff80abb824 000000000000001b > ffffffffffffffff 0000000000000000 0000000000000000 ffffffff80d2ea28 > ffffffff80e10000 ffffffff80ccf9e0 0000000000000001 0000000000000000 > 0000000000000003 0000000000000000 a8000000021fb680 0000000030400080 > 0000000000000000 a8000000021f8000 a8000000021fb880 ffffffff80f00000 > ffffffff801190dc 0000000000000000 0000000000000000 0000000000000000 > 0000000000000000 0000000000000000 ffffffff801190f4 00f87412b0603bdf > ... > Call Trace: > [] show_stack+0x5c/0x150 > [] dump_stack_lvl+0xa4/0xe8 > [] lockdep_rcu_suspicious+0x180/0x228 > [] __lock_acquire+0x15b0/0x2b00 > [] lock_acquire+0x144/0x490 > [] _raw_spin_lock_irqsave+0x54/0x88 > [] ___slab_alloc+0x190/0x950 > [] __kmalloc_noprof+0x344/0x520 > [] __alloc_empty_sheaf+0x48/0x78 > [] __pcs_replace_empty_main+0x4ec/0x680 > [] __kmalloc_noprof+0x45c/0x520 > [] r4k_tlb_uniquify+0x58/0x2c8 > [] r4k_tlb_configure+0xb4/0xd0 > [] tlb_init+0xc/0x80 > [] per_cpu_trap_init+0xfc/0x168 > [] start_secondary+0x28/0x118 > [] mips_cps_core_boot+0x74/0x88 > > However, on that platform even before that you will see various Lockdep RCU > splats complaining about taking the console lock from an offline CPU > originating from c-r4k.c; one more reason to call rcutree_report_cpu_starting() > earlier. Any chance we could conclude on this topic? Kind regards, Stefan