Hello, Paul
when running the rcutorture test with rcutorture.object_debug=1 in
PREEMPT_RT kernel.
BUG: sleeping function called from invalid context at
kernel/locking/spinlock_rt.c:48
[ 3.116503] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid:
1, name: swapper/0
[ 3.116503] preempt_count: 1, expected: 0
[ 3.116503] RCU nest depth: 1, expected: 1
[ 3.116503] 3 locks held by swapper/0/1:
[ 3.116503] #0: ffffffff8f862d80 (fullstop_mutex){+.+.}-{4:4}, at:
torture_init_begin+0x24/0xa0
[ 3.116503] #1: ffffffff8f7b1400 (rcu_read_lock){....}-{1:3}, at:
rcu_torture_init+0x20b9/0x2380
[ 3.116503] #2: ffffffff8f89fa20 (vmap_area_lock){+.+.}-{3:3}, at:
find_vmap_area+0x21/0x90
[ 3.116503] irq event stamp: 571506
[ 3.116503] hardirqs last enabled at (571505):
[<ffffffff8d422ff5>] __call_rcu_common+0x3a5/0xdc0
[ 3.116503] hardirqs last disabled at (571506):
[<ffffffff900487f7>] rcu_torture_init+0x22b7/0x2380
[ 3.116503] softirqs last enabled at (406916):
[<ffffffff8d2e91f2>] __local_bh_enable_ip+0x132/0x170
[ 3.116503] softirqs last disabled at (406910):
[<ffffffff8e658e79>] inet_register_protosw+0x9/0x190
[ 3.116503] Preemption disabled at:
[ 3.116503] [<ffffffff9004865a>] rcu_torture_init+0x211a/0x2380
[ 3.116503] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G W
6.5.0-rc4-rt2-yocto-preempt-rt+ #7
[ 3.116503] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[ 3.116503] Call Trace:
[ 3.116503] <TASK>
[ 3.116503] dump_stack_lvl+0x68/0xb0
[ 3.116503] dump_stack+0x14/0x20
[ 3.116503] __might_resched+0x221/0x2f0
[ 3.116503] rt_spin_lock+0x60/0x130
[ 3.116503] ? find_vmap_area+0x21/0x90
[ 3.116503] find_vmap_area+0x21/0x90
[ 3.116503] vmalloc_dump_obj+0x25/0xa0
[ 3.116503] mem_dump_obj+0x22/0x90
[ 3.116503] __call_rcu_common+0x920/0xdc0
[ 3.116503] ? __pfx_rcu_torture_err_cb+0x10/0x10
[ 3.116503] ? __pfx___call_rcu_common+0x10/0x10
[ 3.116503] ? rcu_torture_init+0x22b7/0x2380
[ 3.116503] ? debug_smp_processor_id+0x1b/0x30
[ 3.116503] ? rcu_is_watching+0x3e/0xc0
[ 3.116503] call_rcu_hurry+0x14/0x20
[ 3.116503] rcu_torture_init+0x2186/0x2380
[ 3.116503] ? __pfx_rcu_torture_init+0x10/0x10
[ 3.116503] ? __pfx_rt_mutex_slowunlock+0x10/0x10
[ 3.116503] ? __pfx_irq_debugfs_init+0x10/0x10
[ 3.116503] ? __pfx_rcu_torture_leak_cb+0x10/0x10
[ 3.116503] ? rt_spin_unlock+0x50/0xa0
[ 3.116503] ? add_device_randomness+0xb1/0xe0
[ 3.116503] ? __pfx_rcu_torture_leak_cb+0x10/0x10
[ 3.116503] ? __pfx_rcu_torture_init+0x10/0x10
[ 3.116503] do_one_initcall+0xd8/0x430
[ 3.116503] ? __pfx_do_one_initcall+0x10/0x10
[ 3.116503] ? __kasan_check_read+0x15/0x20
[ 3.116503] kernel_init_freeable+0x3a0/0x670
[ 3.116503] ? rt_spin_unlock+0x50/0xa0
[ 3.116503] ? __pfx_kernel_init+0x10/0x10
[ 3.116503] kernel_init+0x23/0x160
[ 3.116503] ? __pfx_kernel_init+0x10/0x10
[ 3.116503] ret_from_fork+0x40/0x60
[ 3.116503] ? __pfx_kernel_init+0x10/0x10
[ 3.116503] ret_from_fork_asm+0x1b/0x30
[ 3.116503] </TASK>
[ 3.116503] non-slab/vmalloc memory
as described by Lei Zhen:
v2 --> v3:
1. I made statistics about the source of 'rhp'. kmem_valid_obj() accounts for
more than 97.5%, and vmalloc accounts for less than 1%. So change call
mem_dump_obj() to call kmem_dump_obj() can meet debugging requirements and
avoid the potential deadlock risk of vmalloc_dump_obj().
- mem_dump_obj(rhp);
+ if (kmem_valid_obj(rhp))
+ kmem_dump_obj(rhp);
The discussion about vmap_area_lock deadlock in v2:
https://lkml.org/lkml/2022/11/11/493
so whether mem_dump_obj() should also be replaced by kmem_dump_obj() in
__call_rcu_common(), since the call_rcu() can be called in interrupt context,
this may issue recursive spin vmap_area_lock lock calls.
Any thoughts ?
Thanks
Zqiang
