Re: BUG: sleeping function called from atomic due to "Balance initial LPI affinity across CPUs"

From: John Garry
Date: Wed May 20 2020 - 04:44:56 EST


On 19/05/2020 23:09, Qian Cai wrote:
Reverted the linux-next commit f068a62c548c ("irqchip/gic-v3-its:
Balance initial LPI affinity across CPUs") fixed these warnings during
boot,

Thanks for the notice. So we need the following set to see this:
CONFIG_CPUMASK_OFFSTACK=y
CONFIG_DEBUG_ATOMIC_SLEEP=y
CONFIG_DEBUG_PER_CPU_MAPS=y


its_select_cpu at drivers/irqchip/irq-gic-v3-its.c:1572

[ 332.819381][ T3359] BUG: sleeping function called from invalid
context at mm/slab.h:568
[ 332.827405][ T3359] in_atomic(): 1, irqs_disabled(): 128,
non_block: 0, pid: 3359, name: irqbalance
[ 332.836455][ T3359] INFO: lockdep is turned off.
[ 332.841076][ T3359] irq event stamp: 0
[ 332.844836][ T3359] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[ 332.851828][ T3359] hardirqs last disabled at (0):
[<ffff9000101ea65c>] copy_process+0x98c/0x1f34
[ 332.860710][ T3359] softirqs last enabled at (0):
[<ffff9000101ea690>] copy_process+0x9c0/0x1f34
[ 332.869586][ T3359] softirqs last disabled at (0): [<0000000000000000>] 0x0
[ 332.876560][ T3359] CPU: 155 PID: 3359 Comm: irqbalance Tainted: G
W L 5.7.0-rc6-next-20200519 #1
[ 332.886563][ T3359] Hardware name: HPE Apollo 70
/C01_APACHE_MB , BIOS L50_5.13_1.11 06/18/2019
[ 332.897000][ T3359] Call trace:
[ 332.900151][ T3359] dump_backtrace+0x0/0x22c
[ 332.904514][ T3359] show_stack+0x28/0x34
[ 332.908543][ T3359] dump_stack+0x104/0x194
[ 332.912738][ T3359] ___might_sleep+0x314/0x328
[ 332.917274][ T3359] __might_sleep+0x7c/0xe0
[ 332.921563][ T3359] slab_pre_alloc_hook+0x44/0x8c
[ 332.926360][ T3359] __kmalloc_node+0xb0/0x618
[ 332.930811][ T3359] alloc_cpumask_var_node+0x48/0x94

We could use GFP_ATOMIC flag at the callsite here, but maybe there is a better solution.

[ 332.935868][ T3359] alloc_cpumask_var+0x10/0x1c
[ 332.940496][ T3359] its_select_cpu+0x58/0x2e4
[ 332.944945][ T3359] its_set_affinity+0xe8/0x27c
[ 332.949576][ T3359] msi_domain_set_affinity+0x78/0x114
[ 332.954813][ T3359] irq_do_set_affinity+0x84/0x198
[ 332.959697][ T3359] irq_set_affinity_locked+0x80/0x1a8
[ 332.964927][ T3359] __irq_set_affinity+0x54/0x84
[ 332.969637][ T3359] write_irq_affinity+0x16c/0x198
[ 332.974520][ T3359] irq_affinity_proc_write+0x34/0x44
[ 332.979672][ T3359] pde_write+0x5c/0x78
[ 332.983602][ T3359] proc_reg_write+0x74/0xc0
[ 332.987974][ T3359] __vfs_write+0x84/0x1d8
[ 332.992163][ T3359] vfs_write+0x13c/0x1b8
[ 332.996265][ T3359] ksys_write+0xb0/0x120
[ 333.000385][ T3359] __arm64_sys_write+0x54/0x88
[ 333.005017][ T3359] do_el0_svc+0x128/0x1dc
[ 333.009213][ T3359] el0_sync_handler+0xd0/0x268
[ 333.013836][ T3359] el0_sync+0x164/0x180
[ 336.527739][ T3356] mlx5_core 0000:0b:00.1 enp11s0f1np1: Link down
.