[PATCH] irq-gic-v3: fix NULL dereference of disabled redist_base
From: Heyi Guo
Date: Mon Dec 16 2019 - 01:29:11 EST
If we use ACPI MADT GICC structure to pass single redistributor base,
and mark some GICC as disabled, we'll get below call trace during
boot:
[ 0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
[ 0.000000] GICv3: 256 SPIs implemented
[ 0.000000] GICv3: 0 Extended SPIs implemented
[ 0.000000] GICv3: Distributor has no Range Selector support
[ 0.000000] Unable to handle kernel paging request at virtual address 000000000000ffe8
[ 0.000000] Mem abort info:
[ 0.000000] ESR = 0x96000004
[ 0.000000] EC = 0x25: DABT (current EL), IL = 32 bits
[ 0.000000] SET = 0, FnV = 0
[ 0.000000] EA = 0, S1PTW = 0
[ 0.000000] Data abort info:
[ 0.000000] ISV = 0, ISS = 0x00000004
[ 0.000000] CM = 0, WnR = 0
[ 0.000000] [000000000000ffe8] user address but active_mm is swapper
[ 0.000000] Internal error: Oops: 96000004 [#1] SMP
[ 0.000000] Modules linked in:
[ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.5.0-rc1 #5
[ 0.000000] pstate: 20000085 (nzCv daIf -PAN -UAO)
[ 0.000000] pc : gic_iterate_rdists+0x58/0x130
[ 0.000000] lr : gic_iterate_rdists+0x80/0x130
[ 0.000000] sp : ffff8000113d3cb0
[ 0.000000] x29: ffff8000113d3cb0 x28: 0000000000000000
[ 0.000000] x27: 0000000000000000 x26: 0000000000000018
[ 0.000000] x25: 000000000000ffe8 x24: 000000000000003f
[ 0.000000] x23: ffff800010588040 x22: 00000000000005e8
[ 0.000000] x21: ffff8000113df7d0 x20: 0000030f00003f11
[ 0.000000] x19: 0000000000000000 x18: ffffffffffffffff
[ 0.000000] x17: 0000000014aeb8dc x16: 00000000c3ba0ccf
[ 0.000000] x15: ffff8000113d9908 x14: ffff8000913d3a37
[ 0.000000] x13: ffff8000113d3a45 x12: ffff800011402000
[ 0.000000] x11: ffff8000113d39d0 x10: ffff8000113db980
[ 0.000000] x9 : 00000000ffffffd0 x8 : ffff8000106dca98
[ 0.000000] x7 : 000000000000005b x6 : 0000000000000000
[ 0.000000] x5 : 0000000000000000 x4 : ffff8000128c0000
[ 0.000000] x3 : ffff8000128a0000 x2 : ffff0003fc3c7000
[ 0.000000] x1 : 0000000000000001 x0 : 000000000000ffe8
[ 0.000000] Call trace:
[ 0.000000] gic_iterate_rdists+0x58/0x130
[ 0.000000] gic_init_bases+0x200/0x4b4
[ 0.000000] gic_acpi_init+0x148/0x284
[ 0.000000] acpi_match_madt+0x4c/0x84
[ 0.000000] acpi_table_parse_entries_array+0x188/0x278
[ 0.000000] acpi_table_parse_entries+0x70/0x98
[ 0.000000] acpi_table_parse_madt+0x40/0x50
[ 0.000000] __acpi_probe_device_table+0x88/0xe4
[ 0.000000] irqchip_init+0x38/0x40
[ 0.000000] init_IRQ+0x168/0x19c
[ 0.000000] start_kernel+0x328/0x508
[ 0.000000] Code: f90017b6 9b3a7f16 f8766853 8b190260 (b9400000)
[ 0.000000] ---[ end trace ae5cf232d924bfc1 ]---
[ 0.000000] Kernel panic - not syncing: Fatal exception
[ 0.000000] Rebooting in 3 seconds..
In this case, nr_redist_regions counts all GICC structures but only
enabled ones have redistributor mapped. So add check to avoid NULL
deference of redist_base.
Signed-off-by: Heyi Guo <guoheyi@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jason Cooper <jason@xxxxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
---
drivers/irqchip/irq-gic-v3.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index d6218012097b..bd9d55cadef9 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -781,6 +781,13 @@ static int gic_iterate_rdists(int (*fn)(struct redist_region *, void __iomem *))
u64 typer;
u32 reg;
+ /*
+ * redist_base may be NULL if we use single_redist and some GICC
+ * structure is disabled.
+ */
+ if (!ptr)
+ continue;
+
reg = readl_relaxed(ptr + GICR_PIDR2) & GIC_PIDR2_ARCH_MASK;
if (reg != GIC_PIDR2_ARCH_GICv3 &&
reg != GIC_PIDR2_ARCH_GICv4) { /* We're in trouble... */
--
2.19.1