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Hou Wenlong dc129275a7 KVM: eventfd: Fix false positive RCU usage warning
[ Upstream commit 6a0c61703e3a5d67845a4b275e1d9d7bc1b5aad7 ]

Fix the following false positive warning:
 =============================
 WARNING: suspicious RCU usage
 5.16.0-rc4+ #57 Not tainted
 -----------------------------
 arch/x86/kvm/../../../virt/kvm/eventfd.c:484 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 3 locks held by fc_vcpu 0/330:
  #0: ffff8884835fc0b0 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x88/0x6f0 [kvm]
  #1: ffffc90004c0bb68 (&kvm->srcu){....}-{0:0}, at: vcpu_enter_guest+0x600/0x1860 [kvm]
  #2: ffffc90004c0c1d0 (&kvm->irq_srcu){....}-{0:0}, at: kvm_notify_acked_irq+0x36/0x180 [kvm]

 stack backtrace:
 CPU: 26 PID: 330 Comm: fc_vcpu 0 Not tainted 5.16.0-rc4+
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x44/0x57
  kvm_notify_acked_gsi+0x6b/0x70 [kvm]
  kvm_notify_acked_irq+0x8d/0x180 [kvm]
  kvm_ioapic_update_eoi+0x92/0x240 [kvm]
  kvm_apic_set_eoi_accelerated+0x2a/0xe0 [kvm]
  handle_apic_eoi_induced+0x3d/0x60 [kvm_intel]
  vmx_handle_exit+0x19c/0x6a0 [kvm_intel]
  vcpu_enter_guest+0x66e/0x1860 [kvm]
  kvm_arch_vcpu_ioctl_run+0x438/0x7f0 [kvm]
  kvm_vcpu_ioctl+0x38a/0x6f0 [kvm]
  __x64_sys_ioctl+0x89/0xc0
  do_syscall_64+0x3a/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Since kvm_unregister_irq_ack_notifier() does synchronize_srcu(&kvm->irq_srcu),
kvm->irq_ack_notifier_list is protected by kvm->irq_srcu. In fact,
kvm->irq_srcu SRCU read lock is held in kvm_notify_acked_irq(), making it
a false positive warning. So use hlist_for_each_entry_srcu() instead of
hlist_for_each_entry_rcu().

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
Message-Id: <f98bac4f5052bad2c26df9ad50f7019e40434512.1643265976.git.houwenlong.hwl@antgroup.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-16 12:54:20 +01:00
arch powerpc/fixmap: Fix VM debug warning on unmap 2022-02-16 12:54:19 +01:00
block block: bio-integrity: Advance seed correctly for larger interval sizes 2022-02-08 18:30:35 +01:00
certs
crypto crypto: api - Move cryptomgr soft dependency into algapi 2022-02-11 09:09:03 +01:00
Documentation Revert "fbcon: Disable accelerated scrolling" 2022-02-08 18:30:40 +01:00
drivers net: stmmac: dwmac-sun8i: use return val of readl_poll_timeout() 2022-02-16 12:54:20 +01:00
fs NFSv4 handle port presence in fs_location server string 2022-02-16 12:54:18 +01:00
include PM: hibernate: Remove register_nosave_region_late() 2022-02-16 12:54:20 +01:00
init bpf: Add kconfig knob for disabling unpriv bpf by default 2022-01-05 12:40:34 +01:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:19:10 +01:00
kernel perf: Always wake the parent event 2022-02-16 12:54:20 +01:00
lib lib/test_meminit: destroy cache in kmem_cache_alloc_bulk() test 2022-01-27 10:54:36 +01:00
LICENSES
mm mm/kmemleak: avoid scanning potential huge holes 2022-02-08 18:30:35 +01:00
net net: sched: Clarify error message when qdisc kind is unknown 2022-02-16 12:54:19 +01:00
samples ftrace/samples: Add missing prototypes direct functions 2022-01-11 15:25:00 +01:00
scripts scripts: sphinx-pre-install: Fix ctex support on Debian 2022-01-27 10:54:36 +01:00
security ima: Do not print policy rule with inactive LSM labels 2022-02-16 12:54:16 +01:00
sound ASoC: max9759: fix underflow in speaker_gain_control_put() 2022-02-08 18:30:38 +01:00
tools selftests: nft_concat_range: add test for reload with no element add/del 2022-02-08 18:30:41 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:25:48 +01:00
virt KVM: eventfd: Fix false positive RCU usage warning 2022-02-16 12:54:20 +01:00
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MAINTAINERS MAINTAINERS: adjust GCC PLUGINS after gcc-plugin.sh removal 2021-12-14 11:32:46 +01:00
Makefile Linux 5.10.100 2022-02-11 09:09:03 +01:00
README

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