On 29.09.20 15:13, Stefan Bader wrote:
On 01.09.20 17:10, Greg Kroah-Hartman wrote:
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
commit c330fb1ddc0a922f044989492b7fcca77ee1db46 upstream.
handler data is meant for interrupt handlers and not for storing irq chip
specific information as some devices require handler data to store internal
per interrupt information, e.g. pinctrl/GPIO chained interrupt handlers.
This obviously creates a conflict of interests and crashes the machine
because the XEN pointer is overwritten by the driver pointer.
I cannot say whether this applies the same for the vanilla 4.4 stable kernels
but once this had been applied to our 4.4 based kernels, we observed Xen HVM
guests crashing on boot with:
[ 0.927538] ACPI: bus type PCI registered
[ 0.936008] acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5
[ 0.948739] PCI: Using configuration type 1 for base access
[ 0.960007] PCI: Using configuration type 1 for extended access
[ 0.984340] ACPI: Added _OSI(Module Device)
[ 0.988010] ACPI: Added _OSI(Processor Device)
[ 0.992007] ACPI: Added _OSI(3.0 _SCP Extensions)
[ 0.996013] ACPI: Added _OSI(Processor Aggregator Device)
[ 1.002103] BUG: unable to handle kernel paging request at ffffffffff5f3000
[ 1.004000] IP: [<ffffffff810592ff>] mp_irqdomain_activate+0x5f/0xa0
[ 1.004000] PGD 1e0f067 PUD 1e11067 PMD 1e12067 PTE 0
[ 1.004000] Oops: 0002 [#1] SMP
[ 1.004000] Modules linked in:
[ 1.004000] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 4.4.0-191-generic
#221-Ubuntu
[ 1.004000] Hardware name: Xen HVM domU, BIOS 4.6.5 04/18/2018
[ 1.004000] task: ffff880107db0000 ti: ffff880107dac000 task.ti: ffff880107dac000
[ 1.004000] RIP: 0010:[<ffffffff810592ff>] [<ffffffff810592ff>]
mp_irqdomain_activate+0x5f/0xa0
[ 1.004000] RSP: 0018:ffff880107dafc48 EFLAGS: 00010086
[ 1.004000] RAX: 0000000000000086 RBX: ffff8800eb852140 RCX: 0000000000000000
[ 1.004000] RDX: ffffffffff5f3000 RSI: 0000000000000001 RDI: 000000000020c000
[ 1.004000] RBP: ffff880107dafc50 R08: ffffffff81ebdfd0 R09: 00000000ffffffff
[ 1.004000] R10: 0000000000000011 R11: 0000000000000009 R12: ffff88010880d400
[ 1.004000] R13: 0000000000000001 R14: 0000000000000009 R15: ffff8800eb880080
[ 1.004000] FS: 0000000000000000(0000) GS:ffff880108ec0000(0000)
knlGS:0000000000000000
[ 1.004000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1.004000] CR2: ffffffffff5f3000 CR3: 0000000001e0a000 CR4: 00000000000006f0
[ 1.004000] Stack:
[ 1.004000] ffff88010880bc58 ffff880107dafc70 ffffffff810ea644 ffff88010880bc00
[ 1.004000] ffff88010880bc58 ffff880107dafca0 ffffffff810e6d88 ffffffff810e1009
[ 1.004000] ffff88010880bc00 ffff88010880bca0 ffff8800eb880080 ffff880107dafd38
[ 1.004000] Call Trace:
[ 1.004000] [<ffffffff810ea644>] irq_domain_activate_irq+0x44/0x50
[ 1.004000] [<ffffffff810e6d88>] irq_startup+0x38/0x90
[ 1.004000] [<ffffffff810e1009>] ? vprintk_default+0x29/0x40
[ 1.004000] [<ffffffff810e55e2>] __setup_irq+0x5a2/0x650
[ 1.004000] [<ffffffff811fc064>] ? kmem_cache_alloc_trace+0x1d4/0x1f0
[ 1.004000] [<ffffffff814a3870>] ? acpi_osi_handler+0xb0/0xb0
[ 1.004000] [<ffffffff810e582b>] request_threaded_irq+0xfb/0x1a0
[ 1.004000] [<ffffffff814a3870>] ? acpi_osi_handler+0xb0/0xb0
[ 1.004000] [<ffffffff814bf624>] ? acpi_ev_sci_dispatch+0x64/0x64
[ 1.004000] [<ffffffff814a3f0a>] acpi_os_install_interrupt_handler+0xaa/0x100
[ 1.004000] [<ffffffff81fb26e1>] ? acpi_sleep_proc_init+0x28/0x28
[ 1.004000] [<ffffffff814bf689>] acpi_ev_install_sci_handler+0x23/0x25
[ 1.004000] [<ffffffff814bcf03>] acpi_ev_install_xrupt_handlers+0x1c/0x6c
[ 1.004000] [<ffffffff81fb3e9d>] acpi_enable_subsystem+0x8f/0x93
[ 1.004000] [<ffffffff81fb276c>] acpi_init+0x8b/0x2c4
[ 1.004000] [<ffffffff8141ee1e>] ? kasprintf+0x4e/0x70
[ 1.004000] [<ffffffff81fb26e1>] ? acpi_sleep_proc_init+0x28/0x28
[ 1.004000] [<ffffffff810021f5>] do_one_initcall+0xb5/0x200
[ 1.004000] [<ffffffff810a6fda>] ? parse_args+0x29a/0x4a0
[ 1.004000] [<ffffffff81f69152>] kernel_init_freeable+0x177/0x218
[ 1.004000] [<ffffffff8185dcf0>] ? rest_init+0x80/0x80
[ 1.004000] [<ffffffff8185dcfe>] kernel_init+0xe/0xe0
[ 1.004000] [<ffffffff8186ae92>] ret_from_fork+0x42/0x80
[ 1.004000] [<ffffffff8185dcf0>] ? rest_init+0x80/0x80
[ 1.004000] Code: 8d 1c d2 8d ba 0b 02 00 00 44 8d 51 11 42 8b 14 dd 74 ec 10
82 c1 e7 0c 48 63 ff 81 e2 ff 0f 00 00 48 81 ea 00 10 80 00 48 29 fa <44> 89 12
89 72 10 42 8b 14 dd 74 ec 10 82 83 c1 10 81 e2 ff 0f
[ 1.004000] RIP [<ffffffff810592ff>] mp_irqdomain_activate+0x5f/0xa0
[ 1.004000] RSP <ffff880107dafc48>
[ 1.004000] CR2: ffffffffff5f3000
[ 1.004000] ---[ end trace 3201cae5b6bd7be1 ]---
[ 1.592027] Kernel panic - not syncing: Attempted to kill init!
exitcode=0x00000009
[ 1.592027]
This is from a local server but same stack-trace happens on AWS instances while
initializing ACPI SCI. mp_irqdomain_activate is accessing chip_data expecting
ioapic data there. Oddly enough more recent kernels seem to do the same but not
crashing as HVM guest (neither seen for our 4.15 nor the 5.4).
Hmm, could it be that calling irq_set_chip_data() for a legacy irq is
a rather bad idea?
Could you please try the attached patch (might need some backport, but
should be rather easy)?
Juergen
>From 35b71ae9cc69cdd151cc3a4d587f67eb8d86007d Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@xxxxxxxx>
Date: Tue, 29 Sep 2020 15:47:21 +0200
Subject: [PATCH] xen/events: don't use chip_data for legacy IRQs
Storing Xen specific data via chip_data is fine, as long as this isn't
done for a legacy IRQ.
Use a local array for this purpose in case of legacy IRQs.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
drivers/xen/events/events_base.c | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 90b8f56fbadb..6f02c18fa65c 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -92,6 +92,8 @@ static bool (*pirq_needs_eoi)(unsigned irq);
/* Xen will never allocate port zero for any purpose. */
#define VALID_EVTCHN(chn) ((chn) != 0)
+static struct irq_info *legacy_info_ptrs[NR_IRQS_LEGACY];
+
static struct irq_chip xen_dynamic_chip;
static struct irq_chip xen_percpu_chip;
static struct irq_chip xen_pirq_chip;
@@ -156,7 +158,18 @@ int get_evtchn_to_irq(evtchn_port_t evtchn)
/* Get info for IRQ */
struct irq_info *info_for_irq(unsigned irq)
{
- return irq_get_chip_data(irq);
+ if (irq < nr_legacy_irqs())
+ return legacy_info_ptrs[irq];
+ else
+ return irq_get_chip_data(irq);
+}
+
+static void set_info_for_irq(unsigned int irq, struct irq_info *info)
+{
+ if (irq < nr_legacy_irqs())
+ legacy_info_ptrs[irq] = info;
+ else
+ irq_set_chip_data(irq, info);
}
/* Constructors for packed IRQ information. */
@@ -377,7 +390,7 @@ static void xen_irq_init(unsigned irq)
info->type = IRQT_UNBOUND;
info->refcnt = -1;
- irq_set_chip_data(irq, info);
+ set_info_for_irq(irq, info);
list_add_tail(&info->list, &xen_irq_list_head);
}
@@ -426,14 +439,14 @@ static int __must_check xen_allocate_irq_gsi(unsigned gsi)
static void xen_free_irq(unsigned irq)
{
- struct irq_info *info = irq_get_chip_data(irq);
+ struct irq_info *info = info_for_irq(irq);
if (WARN_ON(!info))
return;
list_del(&info->list);
- irq_set_chip_data(irq, NULL);
+ set_info_for_irq(irq, NULL);
WARN_ON(info->refcnt > 0);
@@ -603,7 +616,7 @@ EXPORT_SYMBOL_GPL(xen_irq_from_gsi);
static void __unbind_from_irq(unsigned int irq)
{
evtchn_port_t evtchn = evtchn_from_irq(irq);
- struct irq_info *info = irq_get_chip_data(irq);
+ struct irq_info *info = info_for_irq(irq);
if (info->refcnt > 0) {
info->refcnt--;
@@ -1108,7 +1121,7 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi,
void unbind_from_irqhandler(unsigned int irq, void *dev_id)
{
- struct irq_info *info = irq_get_chip_data(irq);
+ struct irq_info *info = info_for_irq(irq);
if (WARN_ON(!info))
return;
@@ -1142,7 +1155,7 @@ int evtchn_make_refcounted(evtchn_port_t evtchn)
if (irq == -1)
return -ENOENT;
- info = irq_get_chip_data(irq);
+ info = info_for_irq(irq);
if (!info)
return -ENOENT;
@@ -1170,7 +1183,7 @@ int evtchn_get(evtchn_port_t evtchn)
if (irq == -1)
goto done;
- info = irq_get_chip_data(irq);
+ info = info_for_irq(irq);
if (!info)
goto done;
--
2.26.2
