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I've got a problem that Dom0 hangs without any output from kernel once I enable CONFIG_KPROBE_EVENTS and/or CONFIG_UPROBE_EVENTS in dom0 kernel.

Everything works fine when kprobe/uprobe events are disabled.

My setup:

Board: H3ULCB Kinfisher board

Xen: revision dba774896f7dd74773c14d537643b7d7477fefcd (stable-4.15) https://github.com/xen-project/xen.git;

Kernel: revision 09162bc32c880a791c6c0668ce0745cf7958f576 (v5.10-rc4)

https://github.com/torvalds/linux.git;

kernel config: see attached;

dtb: see attached;

If kprobe/uprobe events are enabled - I see no output after xen switched input to Dom0, if disabled - system boots up successfully.

Both configs work fine when I boot without xen.

Dom0 information from Xen console shows that only one CPU works, and PC stays in "__arch_counter_get_cntvct" function on read_sysreg call.

I did further investigation and found that kernel 5.4 doesn't have such kind of issues.

After bisecting kernel,between 5.10 and 5.4, I found that output disappeared on commit:

76085aff29f585139a37a10ea0a7daa63f70872c

Another issue, which was revealed after I got kernel output was kernel oops with message that CPU is in inconsistent state.

[ 0.415612] EFI services will not be available.

[ 0.420267] smp: Bringing up secondary CPUs ...

[ 0.425185] Detected PIPT I-cache on CPU1

[ 0.425267] Xen: initializing cpu1

[ 0.425292] CPU1: Booted secondary processor 0x0000000001 [0x411fd073]

[ 0.425815] Detected PIPT I-cache on CPU2

[ 0.425879] Xen: initializing cpu2

[ 0.425899] CPU2: Booted secondary processor 0x0000000002 [0x411fd073]

[ 0.426362] Detected PIPT I-cache on CPU3

[ 0.426425] Xen: initializing cpu3

[ 0.426444] CPU3: Booted secondary processor 0x0000000003 [0x411fd073]

[ 0.426537] smp: Brought up 1 node, 4 CPUs

[ 0.472807] SMP: Total of 4 processors activated.

[ 0.477551] CPU features: detected: 32-bit EL0 Support

[ 0.482745] CPU features: detected: CRC32 instructions

[ 0.499470] ------------[ cut here ]------------

[ 0.504034] CPU: CPUs started in inconsistent modes

[ 0.504106] Internal error: aarch64 BRK: f2000800 [#1] PREEMPT SMP

[ 0.515149] Modules linked in:

[ 0.518256] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3-yocto-standard+ #32

[ 0.525942] Hardware name: Renesas H3ULCB Kingfisher board based on r8a7795 ES3.0+ with 8GiB (4 x 2 GiB), running XEN hypervisor (DT)

[ 0.537953] pstate: 60000005 (nZCv daif -PAN -UAO)

[ 0.542801] pc : smp_cpus_done+0x6c/0x98

[ 0.546766] lr : smp_cpus_done+0x6c/0x98

[ 0.550738] sp : ffff8000120dbe10

[ 0.554108] x29: ffff8000120dbe10 x28: 0000000000000000

[ 0.559465] x27: 0000000000000000 x26: 0000000000000000

[ 0.564826] x25: 0000000000000000 x24: 0000000000000000

[ 0.570178] x23: 0000000000000000 x22: ffff800012030000

[ 0.575540] x21: ffff800011806100 x20: ffff8000118a04c4

[ 0.580892] x19: ffff800011d92000 x18: 0000000000000010

[ 0.586249] x17: 00000000b8ee278a x16: 0000000000000012

[ 0.591605] x15: ffff00006f4b0470 x14: ffffffffffffffff

[ 0.596962] x13: 00000000000001c9 x12: 0000000000000001

[ 0.602319] x11: ffff8000120dbe10 x10: ffff8000120dbe10

[ 0.607676] x9 : ffff8000120dbe10 x8 : 0000000000000000

[ 0.613033] x7 : 6574726174732073 x6 : ffff80001203c8f7

[ 0.618390] x5 : 0000000000000000 x4 : 0000000000000000

[ 0.623747] x3 : 00000000ffffffff x2 : ffff80005e4d2000

[ 0.629103] x1 : 0000000000000000 x0 : 0000000000000000

[ 0.634460] Call trace:

[ 0.636969] smp_cpus_done+0x6c/0x98

[ 0.640599] smp_init+0x7c/0x8c

[ 0.643795] kernel_init_freeable+0xfc/0x25c

[ 0.648118] kernel_init+0x14/0x108

[ 0.651660] ret_from_fork+0x10/0x18

[ 0.655294] Code: 540000c0 f0ffebc0 91032000 97a50120 (d4210000)

This problem appears on commit:

f365ab31efacb70bed1e821f7435626e0b2528a6

Both this commits seems to have to direct relation to the problem.

Has anybody met this issue before? Any suggestions will be appreciated.

Please let me know if you need additional information

Best regards,

Oleksii

Dom0 hangs after enable KROBE_EVENTS and/or UPROBE_EVENTS in kernel config