From: Sasha Levin <sashal@kernel•org>
To: linux-kernel@vger•kernel.org, stable@vger•kernel.org
Cc: Sasha Levin <sashal@kernel•org>,
ravi.bangoria@linux•ibm.com,
Fabiano Rosas <farosas@linux•ibm.com>,
Alexey Kardashevskiy <aik@ozlabs•ru>,
nathan@kernel•org, npiggin@gmail•com, bharata@linux•ibm.com,
linuxppc-dev@lists•ozlabs.org
Subject: [PATCH AUTOSEL 5.10 14/34] KVM: PPC: Book3S: Suppress failed alloc warning in H_COPY_TOFROM_GUEST
Date: Mon, 17 Jan 2022 12:03:04 -0500 [thread overview]
Message-ID: <20220117170326.1471712-14-sashal@kernel.org> (raw)
In-Reply-To: <20220117170326.1471712-1-sashal@kernel.org>
From: Alexey Kardashevskiy <aik@ozlabs•ru>
[ Upstream commit 792020907b11c6f9246c21977cab3bad985ae4b6 ]
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
Signed-off-by: Sasha Levin <sashal@kernel•org>
---
arch/powerpc/kvm/book3s_hv_nested.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index a5f1ae892ba68..d0b6c8c16c48a 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -510,7 +510,7 @@ 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;
--
2.34.1
next prev parent reply other threads:[~2022-01-17 17:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220117170326.1471712-1-sashal@kernel.org>
2022-01-17 17:02 ` [PATCH AUTOSEL 5.10 03/34] powerpc/6xx: add missing of_node_put Sasha Levin
2022-01-17 17:02 ` [PATCH AUTOSEL 5.10 04/34] powerpc/powernv: " Sasha Levin
2022-01-17 17:02 ` [PATCH AUTOSEL 5.10 05/34] powerpc/cell: " Sasha Levin
2022-01-17 17:02 ` [PATCH AUTOSEL 5.10 06/34] powerpc/btext: " Sasha Levin
2022-01-17 17:02 ` [PATCH AUTOSEL 5.10 07/34] powerpc/watchdog: Fix missed watchdog reset due to memory ordering race Sasha Levin
2022-01-17 17:02 ` [PATCH AUTOSEL 5.10 09/34] powerpc/smp: Move setup_profiling_timer() under CONFIG_PROFILING Sasha Levin
2022-01-17 17:03 ` [PATCH AUTOSEL 5.10 12/34] powerpc/powermac: Add missing lockdep_register_key() Sasha Levin
2022-01-17 17:03 ` [PATCH AUTOSEL 5.10 13/34] KVM: PPC: Book3S: Suppress warnings when allocating too big memory slots Sasha Levin
2022-01-17 17:03 ` Sasha Levin [this message]
2022-01-17 17:03 ` [PATCH AUTOSEL 5.10 21/34] powerpc/40x: Map 32Mbytes of memory at startup Sasha Levin
2022-01-17 17:03 ` [PATCH AUTOSEL 5.10 22/34] selftests/powerpc/spectre_v2: Return skip code when miss_percent is high Sasha Levin
2022-01-17 17:03 ` [PATCH AUTOSEL 5.10 23/34] powerpc: handle kdump appropriately with crash_kexec_post_notifiers option Sasha Levin
2022-01-17 17:03 ` [PATCH AUTOSEL 5.10 24/34] powerpc/fadump: Fix inaccurate CPU state info in vmcore generated with panic Sasha Levin
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