Commit-ID: 534c89c22e26b183d838294f0937ee092c82ad3a Gitweb: https://git.kernel.org/tip/534c89c22e26b183d838294f0937ee092c82ad3a Author: Kangjie Lu <kjlu@xxxxxxx> AuthorDate: Thu, 14 Mar 2019 00:46:51 -0500 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Thu, 21 Mar 2019 12:24:39 +0100 x86/hyperv: Prevent potential NULL pointer dereference The page allocation in hv_cpu_init() can fail, but the code does not have a check for that. Add a check and return -ENOMEM when the allocation fails. [ tglx: Massaged changelog ] Signed-off-by: Kangjie Lu <kjlu@xxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Mukesh Ojha <mojha@xxxxxxxxxxxxxx> Acked-by: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> Cc: pakki001@xxxxxxx Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx> Cc: Sasha Levin <sashal@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: linux-hyperv@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20190314054651.1315-1-kjlu@xxxxxxx --- arch/x86/hyperv/hv_init.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 6461a16b4559..e4ba467a9fc6 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -103,9 +103,13 @@ static int hv_cpu_init(unsigned int cpu) u64 msr_vp_index; struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()]; void **input_arg; + struct page *pg; input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg); - *input_arg = page_address(alloc_page(GFP_KERNEL)); + pg = alloc_page(GFP_KERNEL); + if (unlikely(!pg)) + return -ENOMEM; + *input_arg = page_address(pg); hv_get_vp_index(msr_vp_index);
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