From: Thomas Gleixner <tglx@linutronix.de> stable inclusion from stable-5.10.47 commit 4df9ed0edb9f6f60afcf1fd70640cebc7eceb3c7 bugzilla: 172973 https://gitee.com/openeuler/kernel/issues/I4DAKB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 7f049fbdd57f6ea71dc741d903c19c73b2f70950 ] XRSTORS requires a valid xstate buffer to work correctly. XSAVES does not guarantee to write a fully valid buffer according to the SDM: "XSAVES does not write to any parts of the XSAVE header other than the XSTATE_BV and XCOMP_BV fields." XRSTORS triggers a #GP: "If bytes 63:16 of the XSAVE header are not all zero." It's dubious at best how this can work at all when the buffer is not zeroed before use. Allocate the buffers with __GFP_ZERO to prevent XRSTORS failure. Fixes: ce711ea3cab9 ("perf/x86/intel/lbr: Support XSAVES/XRSTORS for LBR context switch") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/87wnr0wo2z.ffs@nanos.tec.linutronix.de Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- arch/x86/events/intel/lbr.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c index 6c1231837382..29ec4fe48507 100644 --- a/arch/x86/events/intel/lbr.c +++ b/arch/x86/events/intel/lbr.c @@ -730,7 +730,8 @@ void reserve_lbr_buffers(void) if (!kmem_cache || cpuc->lbr_xsave) continue; - cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache, GFP_KERNEL, + cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache, + GFP_KERNEL | __GFP_ZERO, cpu_to_node(cpu)); } } -- 2.20.1