| Message ID | 20240515152539.18714-1-jgross@suse.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | xen/sched: set all sched_resource data inside locked region for new cpu | expand |
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.cooper3@citrix.com> > Fixes: a8c6c623192e ("sched: clarify use cases of schedule_cpu_switch()") > Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> Tested-by: Andrew Cooper <andrew.cooper3@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. ~Andrew
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.cooper3@citrix.com> >> Fixes: a8c6c623192e ("sched: clarify use cases of schedule_cpu_switch()") >> Signed-off-by: Juergen Gross <jgross@suse.com> > > Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> > Tested-by: Andrew Cooper <andrew.cooper3@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
diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c index 0cb33831d2..babac7aad6 100644 --- a/xen/common/sched/core.c +++ b/xen/common/sched/core.c @@ -3176,6 +3176,8 @@ 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, @@ -3188,8 +3190,6 @@ 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);
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.cooper3@citrix.com> Fixes: a8c6c623192e ("sched: clarify use cases of schedule_cpu_switch()") Signed-off-by: Juergen Gross <jgross@suse.com> --- xen/common/sched/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)