linux-kernel - Re: [PATCH] perf/x86/intel: Fix KASAN global-out-of-bounds warning

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Message-ID: <400d2ef8-07bd-4620-ace8-6eaa05cd200b@intel.com>
Date: Thu, 23 Oct 2025 10:45:40 -0700
From: "Chen, Zide" <zide.chen@...el.com>
To: Dapeng Mi <dapeng1.mi@...ux.intel.com>,
 Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
 Arnaldo Carvalho de Melo <acme@...nel.org>,
 Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>,
 Adrian Hunter <adrian.hunter@...el.com>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Kan Liang <kan.liang@...ux.intel.com>, Andi Kleen <ak@...ux.intel.com>,
 Eranian Stephane <eranian@...gle.com>
Cc: linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
 Dapeng Mi <dapeng1.mi@...el.com>, Xudong Hao <xudong.hao@...el.com>,
 stable@...r.kernel.org
Subject: Re: [PATCH] perf/x86/intel: Fix KASAN global-out-of-bounds warning



On 9/3/2025 6:24 PM, Dapeng Mi wrote:
> When running "perf mem record" command on CWF, the below KASAN
> global-out-of-bounds warning is seen.
> 
>   196.273657] ==================================================================
> [  196.273662] BUG: KASAN: global-out-of-bounds in cmt_latency_data+0x176/0x1b0
> [  196.273669] Read of size 4 at addr ffffffffb721d000 by task dtlb/9850
> 
> [  196.273676] CPU: 126 UID: 0 PID: 9850 Comm: dtlb Kdump: loaded Not tainted 6.17.0-rc3-2025-08-29-intel-next-34160-g316938187eb0 #1 PREEMPT(none)
> [  196.273680] Hardware name: Intel Corporation AvenueCity/AvenueCity, BIOS BHSDCRB1.IPC.3544.P83.2507110208 07/11/2025
> [  196.273682] Call Trace:
> [  196.273683]  <NMI>
> [  196.273684]  dump_stack_lvl+0x55/0x70
> [  196.273689]  print_address_description.constprop.0+0x2c/0x3d0
> [  196.273694]  ? cmt_latency_data+0x176/0x1b0
> [  196.273696]  print_report+0xb4/0x270
> [  196.273699]  ? kasan_addr_to_slab+0xd/0xa0
> [  196.273702]  kasan_report+0xb8/0xf0
> [  196.273705]  ? cmt_latency_data+0x176/0x1b0
> [  196.273707]  cmt_latency_data+0x176/0x1b0
> [  196.273710]  setup_arch_pebs_sample_data+0xf49/0x2560
> [  196.273713]  intel_pmu_drain_arch_pebs+0x577/0xb00
> [  196.273716]  ? __pfx_intel_pmu_drain_arch_pebs+0x10/0x10
> [  196.273719]  ? perf_output_begin+0x3e4/0xa10
> [  196.273724]  ? intel_pmu_drain_bts_buffer+0xc2/0x6a0
> [  196.273727]  ? __pfx_intel_pmu_drain_bts_buffer+0x10/0x10
> [  196.273730]  handle_pmi_common+0x6c4/0xc80
> [  196.273734]  ? __pfx_handle_pmi_common+0x10/0x10
> [  196.273738]  ? intel_bts_interrupt+0xd3/0x4d0
> [  196.273740]  ? __pfx_intel_bts_interrupt+0x10/0x10
> [  196.273742]  ? intel_pmu_lbr_enable_all+0x25/0x150
> [  196.273745]  intel_pmu_handle_irq+0x388/0x700
> [  196.273748]  perf_event_nmi_handler+0xff/0x150
> [  196.273751]  nmi_handle.part.0+0xa8/0x2d0
> [  196.273755]  ? perf_output_begin+0x3e9/0xa10
> [  196.273757]  default_do_nmi+0x79/0x1a0
> [  196.273760]  fred_exc_nmi+0x40/0x90
> [  196.273762]  asm_fred_entrypoint_kernel+0x45/0x60
> [  196.273765] RIP: 0010:perf_output_begin+0x3e9/0xa10
> [  196.273768] Code: 54 24 1c 85 d2 0f 85 19 03 00 00 48 8b 44 24 18 48 c1 e8 03 42 0f b6 04 28 84 c0 74 08 3c 03 0f 8e 25 05 00 00 41 8b 44 24 18 <c1> e0 0c 48 98 48 83 e8 01 80 7c 24 2a 00 0f 85 f9 02 00 00 4c 29
> [  196.273770] RSP: 0018:ffffc9001cf575e8 EFLAGS: 00000246
> [  196.273774] RAX: 0000000000000080 RBX: ffff88c1a0f95028 RCX: 0000000000000004
> [  196.273775] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88c08c8f9408
> 
> [  196.273777] RBP: 0000000000000028 R08: 0000000000000000 R09: ffffed18341f2a05
> [  196.273778] R10: ffff88c1a0f9502f R11: ffff88c1a0dbe1b8 R12: ffff88c1a0f95000
> [  196.273779] R13: dffffc0000000000 R14: 0000000000000000 R15: ffffc9001cf577e0
> [  196.273782]  </NMI>
> 
> The issue is caused by below code in __grt_latency_data(). The code
> tries to access x86_hybrid_pmu structure which doesn't exist on
> non-hybrid platform like CWF.
> 
>         WARN_ON_ONCE(hybrid_pmu(event->pmu)->pmu_type == hybrid_big)
> 
> So add is_hybrid() check before calling this WARN_ON_ONCE to fix the
> global-out-of-bounds access issue.
> 
> Reported-by: Xudong Hao <xudong.hao@...el.com>
> Cc: stable@...r.kernel.org
> Fixes: 090262439f66 ("perf/x86/intel: Rename model-specific pebs_latency_data functions")
> Signed-off-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>
> ---
>  arch/x86/events/intel/ds.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> index c0b7ac1c7594..d1ac1f1ceee9 100644
> --- a/arch/x86/events/intel/ds.c
> +++ b/arch/x86/events/intel/ds.c
> @@ -317,7 +317,7 @@ static u64 __grt_latency_data(struct perf_event *event, u64 status,
>  {
>  	u64 val;
>  
> -	WARN_ON_ONCE(hybrid_pmu(event->pmu)->pmu_type == hybrid_big);
> +	WARN_ON_ONCE(is_hybrid() && hybrid_pmu(event->pmu)->pmu_type == hybrid_big);

BTW, this line has more than 80 characters.

Reviewed-by: Zide Chen <zide.chen@...el.com>


>  
>  	dse &= PERF_PEBS_DATA_SOURCE_GRT_MASK;
>  	val = hybrid_var(event->pmu, pebs_data_source)[dse];
> 
> base-commit: 16ed389227651330879e17bd83d43bd234006722