On 15.05.2024 17:27, Andrew Cooper wrote:
> On 15/05/2024 4:25 pm, Juergen Gross wrote:
>> When adding a cpu to a scheduler, set all data items of struct
>> sched_resource inside the locked region, as otherwise a race might
>> happen (e.g. when trying to access the cpupool of the cpu):
>>
>> (XEN) ----[ Xen-4.19.0-1-d x86_64 debug=y Tainted: H ]----
>> (XEN) CPU: 45
>> (XEN) RIP: e008:[<ffff82d040244cbf>]
>> common/sched/credit.c#csched_load_balance+0x41/0x877
>> (XEN) RFLAGS: 0000000000010092 CONTEXT: hypervisor
>> (XEN) rax: ffff82d040981618 rbx: ffff82d040981618 rcx:
>> 0000000000000000
>> (XEN) rdx: 0000003ff68cd000 rsi: 000000000000002d rdi:
>> ffff83103723d450
>> (XEN) rbp: ffff83207caa7d48 rsp: ffff83207caa7b98 r8:
>> 0000000000000000
>> (XEN) r9: ffff831037253cf0 r10: ffff83103767c3f0 r11:
>> 0000000000000009
>> (XEN) r12: ffff831037237990 r13: ffff831037237990 r14:
>> ffff831037253720
>> (XEN) r15: 0000000000000000 cr0: 000000008005003b cr4:
>> 0000000000f526e0
>> (XEN) cr3: 000000005bc2f000 cr2: 0000000000000010
>> (XEN) fsb: 0000000000000000 gsb: 0000000000000000 gss:
>> 0000000000000000
>> (XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: 0000 cs: e008
>> (XEN) Xen code around <ffff82d040244cbf>
>> (common/sched/credit.c#csched_load_balance+0x41/0x877):
>> (XEN) 48 8b 0c 10 48 8b 49 08 <48> 8b 79 10 48 89 bd b8 fe ff ff 49
>> 8b 4e 28 48
>> <snip>
>> (XEN) Xen call trace:
>> (XEN) [<ffff82d040244cbf>] R
>> common/sched/credit.c#csched_load_balance+0x41/0x877
>> (XEN) [<ffff82d040245a18>] F
>> common/sched/credit.c#csched_schedule+0x36a/0x69f
>> (XEN) [<ffff82d040252644>] F common/sched/core.c#do_schedule+0xe8/0x433
>> (XEN) [<ffff82d0402572dd>] F common/sched/core.c#schedule+0x2e5/0x2f9
>> (XEN) [<ffff82d040232f35>] F common/softirq.c#__do_softirq+0x94/0xbe
>> (XEN) [<ffff82d040232fc8>] F do_softirq+0x13/0x15
>> (XEN) [<ffff82d0403075ef>] F arch/x86/domain.c#idle_loop+0x92/0xe6
>>
>> Reported-by: Andrew Cooper <andrew.coop...@citrix.com>
>> Fixes: a8c6c623192e ("sched: clarify use cases of schedule_cpu_switch()")
>> Signed-off-by: Juergen Gross <jgr...@suse.com>
>
> Acked-by: Andrew Cooper <andrew.coop...@citrix.com>
> Tested-by: Andrew Cooper <andrew.coop...@citrix.com>
>
> Thankyou for the quick turnaround. I'll fix the wrapping of the commit
> message on commit. Not sure what went wrong on my original outgoing email.
Didn't you rush this in a little too fast? No matter how obvious it might seem,
there was no sched/ maintainer ack so far ...
Jan
