75 lines
3.5 KiB
Diff
75 lines
3.5 KiB
Diff
# Commit d104a07524ffc92ae7a70dfe192c291de2a563cc
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# Date 2024-05-15 19:59:52 +0100
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# Author Juergen Gross <jgross@suse.com>
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# Committer Andrew Cooper <andrew.cooper3@citrix.com>
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xen/sched: set all sched_resource data inside locked region for new cpu
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When adding a cpu to a scheduler, set all data items of struct
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sched_resource inside the locked region, as otherwise a race might
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happen (e.g. when trying to access the cpupool of the cpu):
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(XEN) ----[ Xen-4.19.0-1-d x86_64 debug=y Tainted: H ]----
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(XEN) CPU: 45
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(XEN) RIP: e008:[<ffff82d040244cbf>] common/sched/credit.c#csched_load_balance+0x41/0x877
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(XEN) RFLAGS: 0000000000010092 CONTEXT: hypervisor
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(XEN) rax: ffff82d040981618 rbx: ffff82d040981618 rcx: 0000000000000000
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(XEN) rdx: 0000003ff68cd000 rsi: 000000000000002d rdi: ffff83103723d450
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(XEN) rbp: ffff83207caa7d48 rsp: ffff83207caa7b98 r8: 0000000000000000
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(XEN) r9: ffff831037253cf0 r10: ffff83103767c3f0 r11: 0000000000000009
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(XEN) r12: ffff831037237990 r13: ffff831037237990 r14: ffff831037253720
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(XEN) r15: 0000000000000000 cr0: 000000008005003b cr4: 0000000000f526e0
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(XEN) cr3: 000000005bc2f000 cr2: 0000000000000010
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(XEN) fsb: 0000000000000000 gsb: 0000000000000000 gss: 0000000000000000
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(XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: 0000 cs: e008
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(XEN) Xen code around <ffff82d040244cbf> (common/sched/credit.c#csched_load_balance+0x41/0x877):
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(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
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<snip>
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(XEN) Xen call trace:
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(XEN) [<ffff82d040244cbf>] R common/sched/credit.c#csched_load_balance+0x41/0x877
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(XEN) [<ffff82d040245a18>] F common/sched/credit.c#csched_schedule+0x36a/0x69f
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(XEN) [<ffff82d040252644>] F common/sched/core.c#do_schedule+0xe8/0x433
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(XEN) [<ffff82d0402572dd>] F common/sched/core.c#schedule+0x2e5/0x2f9
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(XEN) [<ffff82d040232f35>] F common/softirq.c#__do_softirq+0x94/0xbe
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(XEN) [<ffff82d040232fc8>] F do_softirq+0x13/0x15
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(XEN) [<ffff82d0403075ef>] F arch/x86/domain.c#idle_loop+0x92/0xe6
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(XEN)
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(XEN) Pagetable walk from 0000000000000010:
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(XEN) L4[0x000] = 000000103ff61063 ffffffffffffffff
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(XEN) L3[0x000] = 000000103ff60063 ffffffffffffffff
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(XEN) L2[0x000] = 0000001033dff063 ffffffffffffffff
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(XEN) L1[0x000] = 0000000000000000 ffffffffffffffff
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(XEN)
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(XEN) ****************************************
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(XEN) Panic on CPU 45:
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(XEN) FATAL PAGE FAULT
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(XEN) [error_code=0000]
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(XEN) Faulting linear address: 0000000000000010
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(XEN) ****************************************
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Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
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Fixes: a8c6c623192e ("sched: clarify use cases of schedule_cpu_switch()")
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Signed-off-by: Juergen Gross <jgross@suse.com>
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Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
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Tested-by: Andrew Cooper <andrew.cooper3@citrix.com>
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--- a/xen/common/sched/core.c
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+++ b/xen/common/sched/core.c
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@@ -3179,6 +3179,8 @@ int schedule_cpu_add(unsigned int cpu, s
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sr->scheduler = new_ops;
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sr->sched_priv = ppriv;
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+ sr->granularity = cpupool_get_granularity(c);
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+ sr->cpupool = c;
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/*
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* Reroute the lock to the per pCPU lock as /last/ thing. In fact,
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@@ -3191,8 +3193,6 @@ int schedule_cpu_add(unsigned int cpu, s
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/* _Not_ pcpu_schedule_unlock(): schedule_lock has changed! */
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spin_unlock_irqrestore(old_lock, flags);
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- sr->granularity = cpupool_get_granularity(c);
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- sr->cpupool = c;
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/* The cpu is added to a pool, trigger it to go pick up some work */
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cpu_raise_softirq(cpu, SCHEDULE_SOFTIRQ);
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