Re: Stalls when starting a VSOCK listening socket: soft lockups, RCU stalls, timeout

Jiri Slaby
2026-03-05T17:33:17Z

On 05. 03. 26, 17:16, Thomas Gleixner wrote:
>> Dump of any other's mm_cids needed?
>
> It would be helpful to see the content of all PCPU CIDs and
> tsk::mm_cid::* for all tasks which belong to that process.

Not sure which of the two processes. So both:

crash> rd __per_cpu_offset 4
ffffffff94c38160: ffff8cc799a6c000 ffff8cc799aec000 ................
ffffffff94c38170: ffff8cc799b6c000 ffff8cc799bec000 ................

====== PID 7680 (spinning in mm_get_cid()) ======
4 tasks with
mm = 0xffff8cc406824680
mm_cid.pcpu = 0x66222619df00,

crash> task -x -R mm_cid ffff8cc4038525c0 ffff8cc40ad40000
ffff8cc40683cb80 ffff8cc418424b80
PID: 7680 TASK: ffff8cc4038525c0 CPU: 1 COMMAND: "asm"
mm_cid = {
active = 0x1,
cid = 0x80000000
},

PID: 7681 TASK: ffff8cc40ad40000 CPU: 3 COMMAND: "asm"
mm_cid = {
active = 0x1,
cid = 0x40000000
},

PID: 7682 TASK: ffff8cc40683cb80 CPU: 0 COMMAND: "asm"
mm_cid = {
active = 0x1,
cid = 0x40000002
},

PID: 7684 TASK: ffff8cc418424b80 CPU: 2 COMMAND: "asm"
mm_cid = {
active = 0x1,
cid = 0x40000001
},

crash> struct mm_cid_pcpu -x 0xfffff2e9bfc09f00
struct mm_cid_pcpu {
cid = 0x40000002
}
crash> struct mm_cid_pcpu -x 0xfffff2e9bfc89f00
struct mm_cid_pcpu {
cid = 0x0
}
crash> struct mm_cid_pcpu -x 0xfffff2e9bfd09f00
struct mm_cid_pcpu {
cid = 0x40000001
}
crash> struct mm_cid_pcpu -x 0xfffff2e9bfd89f00
struct mm_cid_pcpu {
cid = 0x40000000
}

====== PID 7508 (sleeping, holding the rq lock) ======
6 tasks with
mm = 0xffff8cc407222340
mm_cid.pcpu = 0x66222619df40,

crash> task -x -R mm_cid ffff8cc43d090000 ffff8cc43d094b80
ffff8cc494a00000 ffff8cc494a04b80 ffff8cc4038b8000 ffff8cc4038bcb80
PID: 7504 TASK: ffff8cc43d090000 CPU: 0 COMMAND: "compile"
mm_cid = {
active = 0x1,
cid = 0x40000001
},

PID: 7505 TASK: ffff8cc43d094b80 CPU: 1 COMMAND: "compile"
mm_cid = {
active = 0x1,
cid = 0x40000003
},

PID: 7506 TASK: ffff8cc494a00000 CPU: 3 COMMAND: "compile"
mm_cid = {
active = 0x1,
cid = 0x40000000
},

PID: 7507 TASK: ffff8cc494a04b80 CPU: 2 COMMAND: "compile"
mm_cid = {
active = 0x1,
cid = 0x40000002
},

PID: 7508 TASK: ffff8cc4038b8000 CPU: 1 COMMAND: "compile"
mm_cid = {
active = 0x1,
cid = 0x40000003
},

PID: 7630 TASK: ffff8cc4038bcb80 CPU: 2 COMMAND: "compile"
mm_cid = {
active = 0x1,
cid = 0x40000002
},

crash> struct mm_cid_pcpu -x 0xfffff2e9bfc09f40
struct mm_cid_pcpu {
cid = 0x40000001
}
crash> struct mm_cid_pcpu -x 0xfffff2e9bfc89f40
struct mm_cid_pcpu {
cid = 0x40000003
}
crash> struct mm_cid_pcpu -x 0xfffff2e9bfd09f40
struct mm_cid_pcpu {
cid = 0x40000002
}
crash> struct mm_cid_pcpu -x 0xfffff2e9bfd89f40
struct mm_cid_pcpu {
cid = 0x40000000
}

Anything else :)?

--
js
suse labs