linux/arch/x86
David Woodhouse 8228c77d8b KVM: x86: switch pvclock_gtod_sync_lock to a raw spinlock
On the preemption path when updating a Xen guest's runstate times, this
lock is taken inside the scheduler rq->lock, which is a raw spinlock.
This was shown in a lockdep warning:

[   89.138354] =============================
[   89.138356] [ BUG: Invalid wait context ]
[   89.138358] 5.15.0-rc5+ #834 Tainted: G S        I E
[   89.138360] -----------------------------
[   89.138361] xen_shinfo_test/2575 is trying to lock:
[   89.138363] ffffa34a0364efd8 (&kvm->arch.pvclock_gtod_sync_lock){....}-{3:3}, at: get_kvmclock_ns+0x1f/0x130 [kvm]
[   89.138442] other info that might help us debug this:
[   89.138444] context-{5:5}
[   89.138445] 4 locks held by xen_shinfo_test/2575:
[   89.138447]  #0: ffff972bdc3b8108 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x77/0x6f0 [kvm]
[   89.138483]  #1: ffffa34a03662e90 (&kvm->srcu){....}-{0:0}, at: kvm_arch_vcpu_ioctl_run+0xdc/0x8b0 [kvm]
[   89.138526]  #2: ffff97331fdbac98 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0xff/0xbd0
[   89.138534]  #3: ffffa34a03662e90 (&kvm->srcu){....}-{0:0}, at: kvm_arch_vcpu_put+0x26/0x170 [kvm]
...
[   89.138695]  get_kvmclock_ns+0x1f/0x130 [kvm]
[   89.138734]  kvm_xen_update_runstate+0x14/0x90 [kvm]
[   89.138783]  kvm_xen_update_runstate_guest+0x15/0xd0 [kvm]
[   89.138830]  kvm_arch_vcpu_put+0xe6/0x170 [kvm]
[   89.138870]  kvm_sched_out+0x2f/0x40 [kvm]
[   89.138900]  __schedule+0x5de/0xbd0

Cc: stable@vger.kernel.org
Reported-by: syzbot+b282b65c2c68492df769@syzkaller.appspotmail.com
Fixes: 30b5c851af ("KVM: x86/xen: Add support for vCPU runstate information")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <1b02a06421c17993df337493a68ba923f3bd5c0f.camel@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-10-25 08:14:38 -04:00
..
boot Kbuild updates for v5.15 2021-09-03 15:33:47 -07:00
configs configs: remove the obsolete CONFIG_INPUT_POLLDEV 2021-09-08 11:50:28 -07:00
crypto crypto: aesni - xts_crypt() return if walk.nbytes is 0 2021-08-27 16:30:19 +08:00
entry compat: remove some compat entry points 2021-09-08 15:32:35 -07:00
events perf/x86/amd/ibs: Add bitfield definitions in new <asm/amd-ibs.h> header 2021-08-26 09:14:36 +02:00
hyperv hyperv-fixes for 5.15-rc2 2021-09-15 17:18:56 -07:00
ia32 binfmt: remove in-tree usage of MAP_DENYWRITE 2021-09-03 18:42:01 +02:00
include KVM: x86: switch pvclock_gtod_sync_lock to a raw spinlock 2021-10-25 08:14:38 -04:00
kernel x86/kvmclock: Move this_cpu_pvti into kvmclock.h 2021-09-30 04:08:01 -04:00
kvm KVM: x86: switch pvclock_gtod_sync_lock to a raw spinlock 2021-10-25 08:14:38 -04:00
lib x86: Add support for 0x22/0x23 port I/O configuration space 2021-08-10 23:31:43 +02:00
math-emu x86/math-emu: Rename frstor() 2021-06-23 18:16:33 +02:00
mm A set of x86 fixes: 2021-09-19 13:29:36 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-07-31 09:14:46 -07:00
pci pci-v5.15-changes 2021-09-07 19:13:42 -07:00
platform EFI changes: two driver API cleanups, and a log message tweak. 2021-06-28 11:34:16 -07:00
power x86/power: Fix kernel-doc warnings in cpu.c 2021-08-12 10:15:40 +02:00
purgatory kernel.h: split out panic and oops helpers 2021-07-01 11:06:04 -07:00
ras
realmode memblock: make memblock_find_in_range method private 2021-09-03 09:58:17 -07:00
tools - Remove cc-option checks which are old and already supported by the 2021-08-30 13:27:16 -07:00
um um: fix stub location calculation 2021-08-26 22:28:03 +02:00
video
xen xen: fix usage of pmd_populate in mremap for pv guests 2021-09-15 08:42:04 +02:00
.gitignore
Kbuild
Kconfig A set of x86 fixes: 2021-09-19 13:29:36 -07:00
Kconfig.assembler
Kconfig.cpu
Kconfig.debug tracing: Refactor TRACE_IRQFLAGS_SUPPORT in Kconfig 2021-08-16 11:37:21 -04:00
Makefile Kbuild updates for v5.15 2021-09-03 15:33:47 -07:00
Makefile_32.cpu x86/build: Do not add -falign flags unconditionally for clang 2021-09-19 10:35:53 +09:00
Makefile.um um: allow not setting extra rpaths in the linux binary 2021-06-17 21:54:15 +02:00