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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 12:43:55 +08:00
linux-next/arch/powerpc/kvm
Paul Mackerras 8f902b005e KVM: PPC: Book3S HV: Fix spinlock/mutex ordering issue in kvmppc_set_lpcr()
Currently, kvmppc_set_lpcr() has a spinlock around the whole function,
and inside that does mutex_lock(&kvm->lock).  It is not permitted to
take a mutex while holding a spinlock, because the mutex_lock might
call schedule().  In addition, this causes lockdep to warn about a
lock ordering issue:

======================================================
[ INFO: possible circular locking dependency detected ]
3.18.0-kvm-04645-gdfea862-dirty #131 Not tainted
-------------------------------------------------------
qemu-system-ppc/8179 is trying to acquire lock:
 (&kvm->lock){+.+.+.}, at: [<d00000000ecc1f54>] .kvmppc_set_lpcr+0xf4/0x1c0 [kvm_hv]

but task is already holding lock:
 (&(&vcore->lock)->rlock){+.+...}, at: [<d00000000ecc1ea0>] .kvmppc_set_lpcr+0x40/0x1c0 [kvm_hv]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&(&vcore->lock)->rlock){+.+...}:
       [<c000000000b3c120>] .mutex_lock_nested+0x80/0x570
       [<d00000000ecc7a14>] .kvmppc_vcpu_run_hv+0xc4/0xe40 [kvm_hv]
       [<d00000000eb9f5cc>] .kvmppc_vcpu_run+0x2c/0x40 [kvm]
       [<d00000000eb9cb24>] .kvm_arch_vcpu_ioctl_run+0x54/0x160 [kvm]
       [<d00000000eb94478>] .kvm_vcpu_ioctl+0x4a8/0x7b0 [kvm]
       [<c00000000026cbb4>] .do_vfs_ioctl+0x444/0x770
       [<c00000000026cfa4>] .SyS_ioctl+0xc4/0xe0
       [<c000000000009264>] syscall_exit+0x0/0x98

-> #0 (&kvm->lock){+.+.+.}:
       [<c0000000000ff28c>] .lock_acquire+0xcc/0x1a0
       [<c000000000b3c120>] .mutex_lock_nested+0x80/0x570
       [<d00000000ecc1f54>] .kvmppc_set_lpcr+0xf4/0x1c0 [kvm_hv]
       [<d00000000ecc510c>] .kvmppc_set_one_reg_hv+0x4dc/0x990 [kvm_hv]
       [<d00000000eb9f234>] .kvmppc_set_one_reg+0x44/0x330 [kvm]
       [<d00000000eb9c9dc>] .kvm_vcpu_ioctl_set_one_reg+0x5c/0x150 [kvm]
       [<d00000000eb9ced4>] .kvm_arch_vcpu_ioctl+0x214/0x2c0 [kvm]
       [<d00000000eb940b0>] .kvm_vcpu_ioctl+0xe0/0x7b0 [kvm]
       [<c00000000026cbb4>] .do_vfs_ioctl+0x444/0x770
       [<c00000000026cfa4>] .SyS_ioctl+0xc4/0xe0
       [<c000000000009264>] syscall_exit+0x0/0x98

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&(&vcore->lock)->rlock);
                               lock(&kvm->lock);
                               lock(&(&vcore->lock)->rlock);
  lock(&kvm->lock);

 *** DEADLOCK ***

2 locks held by qemu-system-ppc/8179:
 #0:  (&vcpu->mutex){+.+.+.}, at: [<d00000000eb93f18>] .vcpu_load+0x28/0x90 [kvm]
 #1:  (&(&vcore->lock)->rlock){+.+...}, at: [<d00000000ecc1ea0>] .kvmppc_set_lpcr+0x40/0x1c0 [kvm_hv]

stack backtrace:
CPU: 4 PID: 8179 Comm: qemu-system-ppc Not tainted 3.18.0-kvm-04645-gdfea862-dirty #131
Call Trace:
[c000001a66c0f310] [c000000000b486ac] .dump_stack+0x88/0xb4 (unreliable)
[c000001a66c0f390] [c0000000000f8bec] .print_circular_bug+0x27c/0x3d0
[c000001a66c0f440] [c0000000000fe9e8] .__lock_acquire+0x2028/0x2190
[c000001a66c0f5d0] [c0000000000ff28c] .lock_acquire+0xcc/0x1a0
[c000001a66c0f6a0] [c000000000b3c120] .mutex_lock_nested+0x80/0x570
[c000001a66c0f7c0] [d00000000ecc1f54] .kvmppc_set_lpcr+0xf4/0x1c0 [kvm_hv]
[c000001a66c0f860] [d00000000ecc510c] .kvmppc_set_one_reg_hv+0x4dc/0x990 [kvm_hv]
[c000001a66c0f8d0] [d00000000eb9f234] .kvmppc_set_one_reg+0x44/0x330 [kvm]
[c000001a66c0f960] [d00000000eb9c9dc] .kvm_vcpu_ioctl_set_one_reg+0x5c/0x150 [kvm]
[c000001a66c0f9f0] [d00000000eb9ced4] .kvm_arch_vcpu_ioctl+0x214/0x2c0 [kvm]
[c000001a66c0faf0] [d00000000eb940b0] .kvm_vcpu_ioctl+0xe0/0x7b0 [kvm]
[c000001a66c0fcb0] [c00000000026cbb4] .do_vfs_ioctl+0x444/0x770
[c000001a66c0fd90] [c00000000026cfa4] .SyS_ioctl+0xc4/0xe0
[c000001a66c0fe30] [c000000000009264] syscall_exit+0x0/0x98

This fixes it by moving the mutex_lock()/mutex_unlock() pair outside
the spin-locked region.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-20 11:41:14 +01:00
..
book3s_32_mmu_host.c KVM: PPC: Book3S: Make magic page properly 4k mappable 2014-07-28 15:23:11 +02:00
book3s_32_mmu.c arch: powerpc: kvm: book3s_32_mmu.c: Remove unused function 2014-12-17 13:12:25 +01:00
book3s_32_sr.S KVM: PPC: book3s_pr: Simplify transitions between virtual and real mode 2011-09-25 19:52:29 +03:00
book3s_64_mmu_host.c KVM: PPC: Book3S: Make magic page properly 4k mappable 2014-07-28 15:23:11 +02:00
book3s_64_mmu_hv.c KVM: PPC: Book3S HV: Remove code for PPC970 processors 2014-12-17 13:44:03 +01:00
book3s_64_mmu.c KVM: PPC: Disable NX for old magic page using guests 2014-05-30 14:26:24 +02:00
book3s_64_slb.S KVM: PPC: Book3S PR: Rework SLB switching code 2014-05-30 14:26:30 +02:00
book3s_64_vio_hv.c KVM: PPC: Book3S: Introduce hypervisor call H_GET_TCE 2014-03-26 23:34:27 +11:00
book3s_64_vio.c ppc: kvm: use anon_inode_getfd() with O_CLOEXEC flag 2013-08-26 13:19:56 +03:00
book3s_emulate.c KVM: PPC: PR: Handle FSCR feature deselects 2014-07-31 10:23:46 +02:00
book3s_exports.c KVM: PPC: Make shared struct aka magic page guest endian 2014-05-30 14:26:21 +02:00
book3s_hv_builtin.c 3.19 changes for KVM: 2014-12-18 16:05:28 -08:00
book3s_hv_interrupts.S powerpc/kvm: Create proper names for the kvm_host_state PMU fields 2014-12-29 15:45:55 +11:00
book3s_hv_ras.c KVM: PPC: Book3S HV: Remove code for PPC970 processors 2014-12-17 13:44:03 +01:00
book3s_hv_rm_mmu.c mm: convert p[te|md]_numa users to p[te|md]_protnone_numa 2015-02-12 18:54:08 -08:00
book3s_hv_rm_xics.c ppc/kvm: Replace ACCESS_ONCE with READ_ONCE 2015-01-19 14:14:07 +01:00
book3s_hv_rmhandlers.S powerpc/kvm: Create proper names for the kvm_host_state PMU fields 2014-12-29 15:45:55 +11:00
book3s_hv.c KVM: PPC: Book3S HV: Fix spinlock/mutex ordering issue in kvmppc_set_lpcr() 2015-03-20 11:41:14 +01:00
book3s_interrupts.S KVM: PPC: Book3S PR: Fix ABIv2 on LE 2014-07-28 15:22:15 +02:00
book3s_mmu_hpte.c kvm: powerpc: book3s: pr: move PR related tracepoints to a separate header 2013-10-17 15:36:22 +02:00
book3s_paired_singles.c arch: powerpc: kvm: book3s_paired_singles.c: Remove unused function 2014-12-17 13:13:29 +01:00
book3s_pr_papr.c KVM: PPC: Book3S PR: Take SRCU read lock around RTAS kvm_read_guest() call 2014-07-28 15:23:16 +02:00
book3s_pr.c arch: powerpc: kvm: book3s_pr.c: Remove unused function 2014-12-17 13:13:16 +01:00
book3s_rmhandlers.S KVM: PPC: Book3S PR: Fix ABIv2 on LE 2014-07-28 15:22:15 +02:00
book3s_rtas.c KVM: PPC: RTAS: Do byte swaps explicitly 2014-07-07 23:17:20 +02:00
book3s_segment.S KVM: PPC: Book3S PR: Handle Facility interrupt and FSCR 2014-05-30 14:26:22 +02:00
book3s_xics.c ppc/kvm: Replace ACCESS_ONCE with READ_ONCE 2015-01-19 14:14:07 +01:00
book3s_xics.h KVM: PPC: Book3S HV: Fix inaccuracies in ICP emulation for H_IPI 2014-12-15 13:27:24 +01:00
book3s.c kvm: add halt_poll_ns module parameter 2015-02-06 13:08:37 +01:00
book3s.h kvm: Fix page ageing bugs 2014-09-24 14:07:58 +02:00
booke_emulate.c KVM: PPC: BOOKE: Emulate debug registers and exception 2014-09-22 10:11:33 +02:00
booke_interrupts.S KVM: PPC: Remove 440 support 2014-07-28 15:23:15 +02:00
booke.c kvm: add halt_poll_ns module parameter 2015-02-06 13:08:37 +01:00
booke.h KVM: PPC: Book3e: Add AltiVec support 2014-09-22 10:11:32 +02:00
bookehv_interrupts.S powerpc/kvm: common sw breakpoint instr across ppc 2014-09-22 10:11:36 +02:00
e500_emulate.c KVM: PPC: Book3e: Add AltiVec support 2014-09-22 10:11:32 +02:00
e500_mmu_host.c treewide: fix typo in printk and Kconfig 2014-11-20 14:56:11 +01:00
e500_mmu_host.h KVM: PPC: E500: Make clear_tlb_refs and clear_tlb1_bitmap static 2013-01-24 19:23:33 +01:00
e500_mmu.c KVM: PPC: e500: Fix bad address type in deliver_tlb_misss() 2014-01-27 16:00:54 +01:00
e500.c 3.19 changes for KVM: 2014-12-18 16:05:28 -08:00
e500.h KVM: PPC: e500mc: Add support for single threaded vcpus on e6500 core 2014-09-22 10:11:35 +02:00
e500mc.c powerpc: Replace __get_cpu_var uses 2014-11-03 12:12:32 +11:00
emulate_loadstore.c KVM: PPC: Pass enum to kvmppc_get_last_inst 2014-09-22 10:11:36 +02:00
emulate.c KVM: PPC: Pass enum to kvmppc_get_last_inst 2014-09-22 10:11:36 +02:00
fpu.S powerpc: Remove fpscr use from [kvm_]cvt_{fd,df} 2010-09-02 14:07:32 +10:00
irq.h KVM: PPC: Book3S: Add API for in-kernel XICS emulation 2013-05-02 15:28:36 +02:00
Kconfig rcu: Make SRCU optional by using CONFIG_SRCU 2015-01-06 11:04:29 -08:00
Makefile Here are the PPC and ARM changes for KVM, which I separated because 2014-08-07 11:35:30 -07:00
mpic.c KVM: irqchip: Provide and use accessors for irq routing table 2014-08-05 14:26:16 +02:00
powerpc.c KVM: remove unneeded return value of vcpu_postcreate 2015-01-23 13:24:52 +01:00
timing.c KVM: PPC: Remove DCR handling 2014-07-28 19:29:15 +02:00
timing.h KVM: PPC: Remove DCR handling 2014-07-28 19:29:15 +02:00
trace_book3s.h KVM: PPC: Book3S HV: Tracepoints for KVM HV guest interactions 2014-12-17 13:29:27 +01:00
trace_booke.h KVM: PPC: BookE: Improve irq inject tracepoint 2014-12-15 13:27:23 +01:00
trace_hv.h KVM: PPC: Book3S HV: Tracepoints for KVM HV guest interactions 2014-12-17 13:29:27 +01:00
trace_pr.h KVM: PPC: Book3S HV: Tracepoints for KVM HV guest interactions 2014-12-17 13:29:27 +01:00
trace.h kvm: powerpc: booke: Move booke related tracepoints to separate header 2013-10-17 15:37:16 +02:00