Messages in this thread | | | Subject | Re: [PATCH] irqchip/gic-v4.1: Use GFP_ATOMIC flag in allocate_vpe_l1_table() | From | Zenghui Yu <> | Date | Mon, 27 Jul 2020 11:50:36 +0800 |
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Hi Marc,
On 2020/6/30 21:37, Zenghui Yu wrote: > Booting the latest kernel with DEBUG_ATOMIC_SLEEP=y on a GICv4.1 enabled > box, I get the following kernel splat: > > [ 0.053766] BUG: sleeping function called from invalid context at mm/slab.h:567 > [ 0.053767] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 0, name: swapper/1 > [ 0.053769] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.8.0-rc3+ #23 > [ 0.053770] Call trace: > [ 0.053774] dump_backtrace+0x0/0x218 > [ 0.053775] show_stack+0x2c/0x38 > [ 0.053777] dump_stack+0xc4/0x10c > [ 0.053779] ___might_sleep+0xfc/0x140 > [ 0.053780] __might_sleep+0x58/0x90 > [ 0.053782] slab_pre_alloc_hook+0x7c/0x90 > [ 0.053783] kmem_cache_alloc_trace+0x60/0x2f0 > [ 0.053785] its_cpu_init+0x6f4/0xe40 > [ 0.053786] gic_starting_cpu+0x24/0x38 > [ 0.053788] cpuhp_invoke_callback+0xa0/0x710 > [ 0.053789] notify_cpu_starting+0xcc/0xd8 > [ 0.053790] secondary_start_kernel+0x148/0x200 > > # ./scripts/faddr2line vmlinux its_cpu_init+0x6f4/0xe40 > its_cpu_init+0x6f4/0xe40: > allocate_vpe_l1_table at drivers/irqchip/irq-gic-v3-its.c:2818 > (inlined by) its_cpu_init_lpis at drivers/irqchip/irq-gic-v3-its.c:3138 > (inlined by) its_cpu_init at drivers/irqchip/irq-gic-v3-its.c:5166 > > It turned out that we're allocating memory using GFP_KERNEL (may sleep) > within the CPU hotplug notifier, which is indeed an atomic context. Bad > thing may happen if we're playing on a system with more than a single > CommonLPIAff group. Avoid it by turning this into an atomic allocation. > > Fixes: 5e5168461c22 ("irqchip/gic-v4.1: VPE table (aka GICR_VPROPBASER) allocation") > Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> > --- > drivers/irqchip/irq-gic-v3-its.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > index 6a5a87fc4601..b66eeca442c4 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -2814,7 +2814,7 @@ static int allocate_vpe_l1_table(void) > if (val & GICR_VPROPBASER_4_1_VALID) > goto out; > > - gic_data_rdist()->vpe_table_mask = kzalloc(sizeof(cpumask_t), GFP_KERNEL); > + gic_data_rdist()->vpe_table_mask = kzalloc(sizeof(cpumask_t), GFP_ATOMIC); > if (!gic_data_rdist()->vpe_table_mask) > return -ENOMEM; > > @@ -2881,7 +2881,7 @@ static int allocate_vpe_l1_table(void) > > pr_debug("np = %d, npg = %lld, psz = %d, epp = %d, esz = %d\n", > np, npg, psz, epp, esz); > - page = alloc_pages(GFP_KERNEL | __GFP_ZERO, get_order(np * PAGE_SIZE)); > + page = alloc_pages(GFP_ATOMIC | __GFP_ZERO, get_order(np * PAGE_SIZE)); > if (!page) > return -ENOMEM; >
Do you mind taking this patch into v5.9? Or please let me know if you still have any concerns on it?
Thanks, Zenghui
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