Subject: Re: [patch V2 00/46] x86, PCI, XEN, genirq ...: Prepare for device MSI

From: Peter Zijlstra <[email-masked]>
Date: Fri, 25 Sep 2020 17:49:37 +0200

On Fri, Sep 25, 2020 at 11:29:13AM -0400, Qian Cai wrote:

> It looks like the crashes happen in the interrupt remapping code where they are
> only able to to generate partial call traces.

> [    8.466614][    T0] BUG: kernel NULL pointer dereference, address: 0000000000000000
> [    8.474295][    T0] #PF: supervisor instruction fetch in kernel mode
> [    8.480669][    T0] #PF: error_code(0x0010) - not-present page
> [    8.486518][    T0] PGD 0 P4D 0 
> [    8.489757][    T0] Oops: 0010 [#1] SMP KASAN PTI
> [    8.494476][    T0] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G          I       5.9.0-rc6-next-20200925 #2
> [    8.503987][    T0] Hardware name: HPE ProLiant DL560 Gen10/ProLiant DL560 Gen10, BIOS U34 11/13/2019
> [    8.513238][    T0] RIP: 0010:0x0
> [    8.516562][    T0] Code: Bad RIP v

Here it looks like this:

[    1.830276] BUG: kernel NULL pointer dereference, address: 0000000000000000
[    1.838043] #PF: supervisor instruction fetch in kernel mode
[    1.844357] #PF: error_code(0x0010) - not-present page
[    1.850090] PGD 0 P4D 0
[    1.852915] Oops: 0010 [#1] SMP
[    1.856419] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.9.0-rc6-00700-g0248dedd12d4 #419
[    1.865447] Hardware name: Intel Corporation S2600GZ/S2600GZ, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013
[    1.876902] RIP: 0010:0x0
[    1.879824] Code: Bad RIP value.
[    1.883423] RSP: 0000:ffffffff82803da0 EFLAGS: 00010282
[    1.889251] RAX: 0000000000000000 RBX: ffffffff8282b980 RCX: ffffffff82803e40
[    1.897241] RDX: 0000000000000001 RSI: ffffffff82803e40 RDI: ffffffff8282b980
[    1.905201] RBP: ffff88842f331000 R08: 00000000ffffffff R09: 0000000000000001
[    1.913162] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000048
[    1.921123] R13: ffffffff82803e40 R14: ffffffff8282b9c0 R15: 0000000000000000
[    1.929085] FS:  0000000000000000(0000) GS:ffff88842f400000(0000) knlGS:0000000000000000
[    1.938113] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.944524] CR2: ffffffffffffffd6 CR3: 0000000002811001 CR4: 00000000000606b0
[    1.952484] Call Trace:
[    1.955214]  msi_domain_alloc+0x36/0x130
[    1.959594]  __irq_domain_alloc_irqs+0x165/0x380
[    1.964748]  dmar_alloc_hwirq+0x9a/0x120
[    1.969127]  dmar_set_interrupt.part.0+0x1c/0x60
[    1.974281]  enable_drhd_fault_handling+0x2c/0x6c
[    1.979532]  apic_intr_mode_init+0xfa/0x100
[    1.984191]  x86_late_time_init+0x20/0x30
[    1.988662]  start_kernel+0x723/0x7e6
[    1.992748]  secondary_startup_64_no_verify+0xa6/0xab
[    1.998386] Modules linked in:
[    2.001794] CR2: 0000000000000000
[    2.005510] ---[ end trace 837dc60d7c66efa2 ]---