[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.17] xen/sched: set all sched_resource data inside locked region for new cpu
commit a14a7b92af452ac61990b9cb514266935bff7a0b Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Tue May 21 12:01:06 2024 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Tue May 21 12:01:06 2024 +0200 xen/sched: set all sched_resource data inside locked region for new cpu 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 (XEN) (XEN) Pagetable walk from 0000000000000010: (XEN) L4[0x000] = 000000103ff61063 ffffffffffffffff (XEN) L3[0x000] = 000000103ff60063 ffffffffffffffff (XEN) L2[0x000] = 0000001033dff063 ffffffffffffffff (XEN) L1[0x000] = 0000000000000000 ffffffffffffffff (XEN) (XEN) **************************************** (XEN) Panic on CPU 45: (XEN) FATAL PAGE FAULT (XEN) [error_code=0000] (XEN) Faulting linear address: 0000000000000010 (XEN) **************************************** Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Fixes: a8c6c623192e ("sched: clarify use cases of schedule_cpu_switch()") Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Tested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> master commit: d104a07524ffc92ae7a70dfe192c291de2a563cc master date: 2024-05-15 19:59:52 +0100 --- xen/common/sched/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c index 29bbab5ac6..a9ff98f67a 100644 --- a/xen/common/sched/core.c +++ b/xen/common/sched/core.c @@ -3179,6 +3179,8 @@ int schedule_cpu_add(unsigned int cpu, struct cpupool *c) sr->scheduler = new_ops; sr->sched_priv = ppriv; + sr->granularity = cpupool_get_granularity(c); + sr->cpupool = c; /* * Reroute the lock to the per pCPU lock as /last/ thing. In fact, @@ -3191,8 +3193,6 @@ int schedule_cpu_add(unsigned int cpu, struct cpupool *c) /* _Not_ pcpu_schedule_unlock(): schedule_lock has changed! */ spin_unlock_irqrestore(old_lock, flags); - sr->granularity = cpupool_get_granularity(c); - sr->cpupool = c; /* The cpu is added to a pool, trigger it to go pick up some work */ cpu_raise_softirq(cpu, SCHEDULE_SOFTIRQ); -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.17
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