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| author | Alexey Kardashevskiy <aik@ozlabs.ru> | 2021-09-01 18:45:50 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-12-02 22:56:08 +1100 |
| commit | 792020907b11c6f9246c21977cab3bad985ae4b6 (patch) | |
| tree | 50b95a494699b5e9842d2f3b854b4db9c1999b0e /arch | |
| parent | 511d25d6b789fffcb20a3eb71899cf974a31bd9d (diff) | |
| download | linux-stable-792020907b11c6f9246c21977cab3bad985ae4b6.tar.gz linux-stable-792020907b11c6f9246c21977cab3bad985ae4b6.tar.bz2 linux-stable-792020907b11c6f9246c21977cab3bad985ae4b6.zip | |
KVM: PPC: Book3S: Suppress failed alloc warning in H_COPY_TOFROM_GUEST
H_COPY_TOFROM_GUEST is an hcall for an upper level VM to access its nested
VMs memory. The userspace can trigger WARN_ON_ONCE(!(gfp & __GFP_NOWARN))
in __alloc_pages() by constructing a tiny VM which only does
H_COPY_TOFROM_GUEST with a too big GPR9 (number of bytes to copy).
This silences the warning by adding __GFP_NOWARN.
Spotted by syzkaller.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210901084550.1658699-1-aik@ozlabs.ru
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_nested.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c index e57c08b968c0..a2e34efb8d31 100644 --- a/arch/powerpc/kvm/book3s_hv_nested.c +++ b/arch/powerpc/kvm/book3s_hv_nested.c @@ -580,7 +580,7 @@ long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu) if (eaddr & (0xFFFUL << 52)) return H_PARAMETER; - buf = kzalloc(n, GFP_KERNEL); + buf = kzalloc(n, GFP_KERNEL | __GFP_NOWARN); if (!buf) return H_NO_MEM; |