diff options
| author | Mostafa Saleh <smostafa@google.com> | 2025-06-25 15:30:58 +0300 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2025-06-26 10:05:04 +0300 |
| commit | 9a2b9416fd1d18d97ce1b737a11fcbc521140e5d (patch) | |
| tree | 39c3a7d1408a9b560f08714adcf5dcabdc8ee7d7 | |
| parent | e728e705802fec20f65d974a5d5eb91217ac618d (diff) | |
| download | linux-9a2b9416fd1d18d97ce1b737a11fcbc521140e5d.tar.xz | |
KVM: arm64: Fix error path in init_hyp_mode()
In the unlikely case pKVM failed to allocate carveout, the error path
tries to access NULL ptr when it de-reference the SVE state from the
uninitialized nVHE per-cpu base.
[ 1.575420] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[ 1.576010] pc : teardown_hyp_mode+0xe4/0x180
[ 1.576920] lr : teardown_hyp_mode+0xd0/0x180
[ 1.577308] sp : ffff8000826fb9d0
[ 1.577600] x29: ffff8000826fb9d0 x28: 0000000000000000 x27: ffff80008209b000
[ 1.578383] x26: ffff800081dde000 x25: ffff8000820493c0 x24: ffff80008209eb00
[ 1.579180] x23: 0000000000000040 x22: 0000000000000001 x21: 0000000000000000
[ 1.579881] x20: 0000000000000002 x19: ffff800081d540b8 x18: 0000000000000000
[ 1.580544] x17: ffff800081205230 x16: 0000000000000152 x15: 00000000fffffff8
[ 1.581183] x14: 0000000000000008 x13: fff00000ff7f6880 x12: 000000000000003e
[ 1.581813] x11: 0000000000000002 x10: 00000000000000ff x9 : 0000000000000000
[ 1.582503] x8 : 0000000000000000 x7 : 7f7f7f7f7f7f7f7f x6 : 43485e525851ff30
[ 1.583140] x5 : fff00000ff6e9030 x4 : fff00000ff6e8f80 x3 : 0000000000000000
[ 1.583780] x2 : 0000000000000000 x1 : 0000000000000002 x0 : 0000000000000000
[ 1.584526] Call trace:
[ 1.584945] teardown_hyp_mode+0xe4/0x180 (P)
[ 1.585578] init_hyp_mode+0x920/0x994
[ 1.586005] kvm_arm_init+0xb4/0x25c
[ 1.586387] do_one_initcall+0xe0/0x258
[ 1.586819] do_initcall_level+0xa0/0xd4
[ 1.587224] do_initcalls+0x54/0x94
[ 1.587606] do_basic_setup+0x1c/0x28
[ 1.587998] kernel_init_freeable+0xc8/0x130
[ 1.588409] kernel_init+0x20/0x1a4
[ 1.588768] ret_from_fork+0x10/0x20
[ 1.589568] Code: f875db48 8b1c0109 f100011f 9a8903e8 (f9463100)
[ 1.590332] ---[ end trace 0000000000000000 ]---
As Quentin pointed, the order of free is also wrong, we need to free
SVE state first before freeing the per CPU ptrs.
I initially observed this on 6.12, but I could also repro in master.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
Fixes: 66d5b53e20a6 ("KVM: arm64: Allocate memory mapped at hyp for host sve state in pKVM")
Reviewed-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250625123058.875179-1-smostafa@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
| -rw-r--r-- | arch/arm64/kvm/arm.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 38a91bb5d4c7..6bdf79bc5d95 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -2346,7 +2346,9 @@ static void __init teardown_hyp_mode(void) free_hyp_pgds(); for_each_possible_cpu(cpu) { free_pages(per_cpu(kvm_arm_hyp_stack_base, cpu), NVHE_STACK_SHIFT - PAGE_SHIFT); - free_pages(kvm_nvhe_sym(kvm_arm_hyp_percpu_base)[cpu], nvhe_percpu_order()); + + if (!kvm_nvhe_sym(kvm_arm_hyp_percpu_base)[cpu]) + continue; if (free_sve) { struct cpu_sve_state *sve_state; @@ -2354,6 +2356,9 @@ static void __init teardown_hyp_mode(void) sve_state = per_cpu_ptr_nvhe_sym(kvm_host_data, cpu)->sve_state; free_pages((unsigned long) sve_state, pkvm_host_sve_state_order()); } + + free_pages(kvm_nvhe_sym(kvm_arm_hyp_percpu_base)[cpu], nvhe_percpu_order()); + } } |