On Tue, Jan 09, 2024 at 10:51:27AM -0500, Liam R. Howlett wrote:
> * Paul E. McKenney <paulmck@xxxxxxxxxx> [240109 09:04]:
> > Hello!
> >
> > I get the splat shown below when running rcutorture on next-20240108
> > (and some less-recent -next versions) on scenarios that run KASAN and
> > that also enable CONFIG_DEBUG_LOCK_ALLOC=y. I am running gcc 8.5.0.
> >
> > Bisection fingers this commit:
> >
> > a414d4286f34 ("kasan: handle concurrent kasan_record_aux_stack calls")
> >
> > This commit does not appear to be trying to change the annotation
> > required of KASAN users, so I suspect that the commit is at fault. I am
> > including Liam in case Maple Tree is the bad guy, and should call_rcu()
> > need adjustment, here I am. ;-)
> >
> > Thoughts?
>
>
> I think this is ma_free_rcu() registering mt_free_rcu() in
> lib/maple_tree.c.
>
> The commit you point to saves and restores the irq state in
> __kasan_record_aux_stack(), but the trace below shows it is called prior
> to irqs being initialized. This isn't what lockdep is yelling about, so
> what am I missing? Maybe it will be caught after this issue is
> resolved?
>
> I am also guessing maple tree shows up in the stack trace because it is
> the very first rcu user at boot (just like the rcutiny issue last time).
> I'm just keeping everyone honest/angry.
That is my guess as well, but I wouldn't want you to feel left out. ;-)
Thanx, Paul
> > ------------------------------------------------------------------------
> >
> > [ 0.174878] INFO: trying to register non-static key.
> > [ 0.174879] The code is fine but needs lockdep annotation, or maybe
> > [ 0.174880] you didn't initialize this object before use?
> > [ 0.174881] turning off the locking correctness validator.
> > [ 0.174884] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.7.0-rc4-00331-ga414d4286f34 #39616
> > [ 0.174888] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
> > [ 0.174891] Call Trace:
> > [ 0.174892] <TASK>
> > [ 0.174895] dump_stack_lvl+0x36/0x50
> > [ 0.174903] register_lock_class+0x1240/0x1880
> > [ 0.174910] ? kasan_save_stack+0x2e/0x40
> > [ 0.174916] ? kasan_save_stack+0x20/0x40
> > [ 0.174919] ? __kasan_record_aux_stack+0x91/0xe0
> > [ 0.174923] ? __call_rcu_common.constprop.84+0x99/0x740
> > [ 0.174927] ? mas_wr_node_store+0x8c6/0x1700
> > [ 0.174931] ? mas_wr_modify+0x274/0x2500
> > [ 0.174934] ? mas_wr_store_entry+0x3fa/0x1830
> > [ 0.174938] ? mas_store_gfp+0xaa/0x140
> > [ 0.174941] ? __pfx_register_lock_class+0x10/0x10
> > [ 0.174945] ? x86_64_start_reservations+0x18/0x30
> > [ 0.174952] ? x86_64_start_kernel+0x91/0xa0
> > [ 0.174956] ? secondary_startup_64_no_verify+0x178/0x17b
> > [ 0.174961] ? __pfx_lock_release+0x10/0x10
> > [ 0.174965] ? do_raw_spin_lock+0x125/0x290
> > [ 0.174968] ? __pfx_do_raw_spin_lock+0x10/0x10
> > [ 0.174971] __lock_acquire.isra.27+0x81/0x10d0
> > [ 0.174976] ? _raw_spin_unlock_irqrestore+0x22/0x50
> > [ 0.174982] ? debug_object_active_state+0x2e7/0x430
> > [ 0.174988] lock_acquire+0x11e/0x280
> > [ 0.174992] ? __kasan_record_aux_stack+0xa1/0xe0
> > [ 0.174996] _raw_spin_lock_irqsave+0x2f/0x50
> > [ 0.175000] ? __kasan_record_aux_stack+0xa1/0xe0
> > [ 0.175003] __kasan_record_aux_stack+0xa1/0xe0
> > [ 0.175006] ? __pfx_mt_free_rcu+0x10/0x10
> > [ 0.175009] __call_rcu_common.constprop.84+0x99/0x740
> > [ 0.175012] ? mas_alloc_nodes+0x3e7/0x750
> > [ 0.175015] ? mas_pop_node+0x192/0x290
> > [ 0.175018] mas_wr_node_store+0x8c6/0x1700
> > [ 0.175022] ? __free_zapped_classes+0x2af/0x2f0
> > [ 0.175026] ? lock_release+0x1e3/0x660
> > [ 0.175030] ? __pfx_mas_wr_node_store+0x10/0x10
> > [ 0.175033] ? __pfx_lock_release+0x10/0x10
> > [ 0.175038] ? lock_acquire+0x11e/0x280
> > [ 0.175042] ? stack_depot_save_flags+0x148/0x650
> > [ 0.175047] ? find_held_lock+0x33/0x1c0
> > [ 0.175051] ? lock_release+0x1e3/0x660
> > [ 0.175054] ? pcpu_alloc+0x81d/0xa30
> > [ 0.175059] ? stack_depot_save_flags+0x1da/0x650
> > [ 0.175062] ? __pfx_lock_release+0x10/0x10
> > [ 0.175066] ? register_lock_class+0xc9/0x1880
> > [ 0.175070] ? pcpu_alloc+0x60e/0xa30
> > [ 0.175074] mas_wr_modify+0x274/0x2500
> > [ 0.175078] ? __mutex_unlock_slowpath+0x176/0x660
> > [ 0.175083] mas_wr_store_entry+0x3fa/0x1830
> > [ 0.175088] mas_store_gfp+0xaa/0x140
> > [ 0.175092] ? __pfx_mas_store_gfp+0x10/0x10
> > [ 0.175097] ? lockdep_init_map_type+0x2c8/0x7a0
> > [ 0.175101] irq_insert_desc+0xaf/0x100
> > [ 0.175107] ? __pfx_irq_insert_desc+0x10/0x10
> > [ 0.175110] ? kobject_init+0x68/0x1e0
> > [ 0.175115] ? kmem_cache_create_usercopy+0xce/0x240
> > [ 0.175119] early_irq_init+0x10f/0x140
>
> IRQs are not enabled at this point.
>
> > [ 0.175125] start_kernel+0x177/0x3a0
> > [ 0.175129] x86_64_start_reservations+0x18/0x30
> > [ 0.175133] x86_64_start_kernel+0x91/0xa0
> > [ 0.175138] secondary_startup_64_no_verify+0x178/0x17b
> > [ 0.175143] </TASK>
> >
