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Message-ID: <6c4a3b2b-d207-466e-bd58-05566f36e1a4@linux.intel.com>
Date: Tue, 30 Sep 2025 14:19:25 +0800
From: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>
To: Oliver Sang <oliver.sang@...el.com>
Cc: oe-lkp@...ts.linux.dev, lkp@...el.com,
Kan Liang <kan.liang@...ux.intel.com>, linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org, 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>,
Andi Kleen <ak@...ux.intel.com>, Eranian Stephane <eranian@...gle.com>,
Dapeng Mi <dapeng1.mi@...el.com>
Subject: Re: [Patch v7 02/12] perf/x86/intel: Fix NULL event access and
potential PEBS record loss
On 9/30/2025 1:19 PM, Oliver Sang wrote:
> hi, Dapeng,
>
> On Sun, Sep 28, 2025 at 02:00:28PM +0800, Mi, Dapeng wrote:
>> Hi Oliver,
>>
>> Could you please help to validate the attached patch? The patch should fix
>> this warning. (Please apply this patch on top of the whole patch series).
>> Thanks.
> the patch doesn't fix the warning [1]. one dmesg is attached FYI.
>
> BTW, I applied this patch on top of the patch set, and the patch set itself
> is applied upon f49e1be1954248. as below.
> if any problem, please let us know. thanks
>
> * f7171f90cc3a45 perf/x86/intel: Fix NULL event access waring from test robot
> * 81248d31dd384c perf/x86/intel: Add counter group support for arch-PEBS
> * c4dd1608098ec0 perf/x86/intel: Setup PEBS data configuration and enable legacy groups
> * de78881cd5ac79 perf/x86/intel: Update dyn_constranit base on PEBS event precise level
> * f560ef321b0632 perf/x86/intel: Allocate arch-PEBS buffer and initialize PEBS_BASE MSR
> * 5411e99084e21d perf/x86/intel: Process arch-PEBS records or record fragments
> * d721d0d90c7b30 perf/x86/intel/ds: Factor out PEBS group processing code to functions
> * 0cd78a2875e1ab perf/x86/intel/ds: Factor out PEBS record processing code to functions
> * cc5755ee9b8bb2 perf/x86/intel: Initialize architectural PEBS
> * 995af2a15982ff perf/x86/intel: Correct large PEBS flag check
> * fa9540afb72301 perf/x86/intel: Replace x86_pmu.drain_pebs calling with static call
> * a7138973beb1d1 perf/x86/intel: Fix NULL event access and potential PEBS record loss
> * 0c9567b36ae6f8 perf/x86: Remove redundant is_x86_event() prototype
> * f49e1be1954248 perf/x86: Print PMU counters bitmap in x86_pmu_show_pmu_cap()
>
> commit f7171f90cc3a45627643d4eadd204e2b8f45e540
> Author: Dapeng Mi <dapeng1.mi@...ux.intel.com>
> Date: Sun Sep 28 13:50:47 2025 +0800
>
> perf/x86/intel: Fix NULL event access waring from test robot
>
> This patch fixes the warning about
> https://lore.kernel.org/all/202509081646.d101cfb7-lkp@intel.com/.
>
> Signed-off-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>
>
> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> index 65908880f4244..ef32714cb1822 100644
> --- a/arch/x86/events/intel/ds.c
> +++ b/arch/x86/events/intel/ds.c
> @@ -2821,8 +2821,11 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
> * If collision happened, the record will be dropped.
> */
> if (pebs_status != (1ULL << bit)) {
> - for_each_set_bit(i, (unsigned long *)&pebs_status, size)
> + for_each_set_bit(i, (unsigned long *)&pebs_status, size) {
> error[i]++;
> + if (error[i] && !events[i])
> + events[i] = cpuc->events[i];
> + }
> continue;
> }
Oops, it looks previous fix was incomplete. :(
Oliver, could you please verify the new attached patch (Please apply this
patch on top of the whole patch series)? Thanks a lot for your effort.
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 65908880f424..3dedf7a0acf6 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2781,9 +2781,11 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs
*iregs, struct perf_sample_d
/* PEBS v3 has more accurate status bits */
if (x86_pmu.intel_cap.pebs_format >= 3) {
- for_each_set_bit(bit, (unsigned long *)&pebs_status, size)
+ for_each_set_bit(bit, (unsigned long *)&pebs_status, size) {
counts[bit]++;
-
+ if (counts[bit] && !events[bit])
+ events[bit] = cpuc->events[bit];
+ }
continue;
}
@@ -2821,8 +2823,11 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs
*iregs, struct perf_sample_d
* If collision happened, the record will be dropped.
*/
if (pebs_status != (1ULL << bit)) {
- for_each_set_bit(i, (unsigned long *)&pebs_status, size)
+ for_each_set_bit(i, (unsigned long *)&pebs_status, size) {
error[i]++;
+ if (error[i] && !events[i])
+ events[i] = cpuc->events[i];
+ }
continue;
}
>
>
>
>
> [1]
> [ 101.198733][ C0] ------------[ cut here ]------------
> [ 101.198737][ C0] WARNING: CPU: 0 PID: 2770 at arch/x86/events/intel/ds.c:2849 intel_pmu_drain_pebs_nhm+0x589/0x630
> [ 101.198758][ C0] Modules linked in: xt_conntrack nft_chain_nat xt_MASQUERADE nf_nat nf_conntrack_netlink nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
> xt_addrtype nft_compat nf_tables nfnetlink br_netfilter bridge stp llc dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio qrtr sg binfmt_misc loop fus
> e dm_mod overlay btrfs blake2b_generic xor raid6_pq intel_rapl_msr intel_rapl_common intel_uncore_frequency intel_uncore_frequency_common skx_edac skx_eda
> c_common nfit libnvdimm x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel irdma ice kvm sd_mod ast irqbypass snd_pcm gnss ghash_clmulni_intel drm_c
> lient_lib snd_timer drm_shmem_helper rapl ib_uverbs snd ipmi_ssif ahci drm_kms_helper intel_cstate soundcore libahci mei_me acpi_power_meter i2c_i801 ioat
> dma intel_uncore drm ib_core pcspkr libata ipmi_si acpi_ipmi mei joydev i2c_smbus intel_pch_thermal lpc_ich dca wmi ipmi_devintf ipmi_msghandler acpi_pad
> [ 101.198862][ C0] CPU: 0 UID: 0 PID: 2770 Comm: perf Tainted: G S 6.17.0-rc1-00063-gf7171f90cc3a #1 VOLUNTARY
> [ 101.198871][ C0] Tainted: [S]=CPU_OUT_OF_SPEC
> [ 101.198873][ C0] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
> [ 101.198877][ C0] RIP: 0010:intel_pmu_drain_pebs_nhm+0x589/0x630
> [ 101.198885][ C0] Code: 48 e8 1b bd fe ff 85 c0 0f 84 a9 00 00 00 41 f6 84 24 a4 01 00 00 80 0f 84 9a 00 00 00 4c 89 ef e8 bc 29 34 00 e9 a9 fc ff ff
> <0f> 0b e9 a2 fc ff ff 0f 0b e9 9b fc ff ff 48 8b 04 cb 48 89 84 cc
> [ 101.198890][ C0] RSP: 0018:fffffe000000d8c0 EFLAGS: 00010046
> [ 101.198895][ C0] RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000001
> [ 101.198898][ C0] RDX: 0000000000000001 RSI: 0000000000000004 RDI: fffffe000000d900
> [ 101.198901][ C0] RBP: fffffe000002c0c8 R08: 0000000000000001 R09: 0000000000000000
> [ 101.198904][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
> [ 101.198905][ C0] R13: 0000000000000000 R14: fffffe000000dc80 R15: 0000000000000001
> [ 101.198908][ C0] FS: 00007f96c7747840(0000) GS:ffff88bffb7e0000(0000) knlGS:0000000000000000
> [ 101.198913][ C0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 101.198916][ C0] CR2: 00000000004ac270 CR3: 000000021df93005 CR4: 00000000007727f0
> [ 101.198920][ C0] PKRU: 55555554
> [ 101.198922][ C0] Call Trace:
> [ 101.198927][ C0] <NMI>
> [ 101.198942][ C0] handle_pmi_common+0x2e1/0x4b0
> [ 101.198965][ C0] intel_pmu_handle_irq+0x109/0x2b0
> [ 101.198967][ C0] perf_event_nmi_handler+0x2a/0x70
> [ 101.198974][ C0] nmi_handle+0x53/0x130
> [ 101.198979][ C0] default_do_nmi+0x11d/0x170
> [ 101.198988][ C0] exc_nmi+0x106/0x1b0
> [ 101.198990][ C0] end_repeat_nmi+0xf/0x53
> [ 101.198995][ C0] RIP: 0010:clear_bhb_loop+0x5e/0x80
> [ 101.198997][ C0] Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc
> <b8> 05 00 00 00 eb 01 90 83 e8 01 75 f8 83 e9 01 75 bb c3 cc cc cc
> [ 101.198998][ C0] RSP: 0018:ffffc90025163f30 EFLAGS: 00000002
> [ 101.199000][ C0] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000004
> [ 101.199001][ C0] RDX: 0000000000000000 RSI: 0000000000000010 RDI: ffffc90025163f58
> [ 101.199002][ C0] RBP: ffffc90025163f48 R08: 0000000000000000 R09: 0000000000000000
> [ 101.199004][ C0] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> [ 101.199004][ C0] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> [ 101.199007][ C0] ? clear_bhb_loop+0x5e/0x80
> [ 101.199010][ C0] ? clear_bhb_loop+0x5e/0x80
> [ 101.199011][ C0] </NMI>
> [ 101.199012][ C0] <TASK>
> [ 101.199012][ C0] ? clear_bhb_loop+0x30/0x80
> [ 101.199014][ C0] ? clear_bhb_loop+0x30/0x80
> [ 101.199016][ C0] ? clear_bhb_loop+0xe/0x80
> [ 101.199017][ C0] ? entry_SYSCALL_64_after_hwframe+0x71/0x7e
> [ 101.199020][ C0] </TASK>
> [ 101.199020][ C0] ---[ end trace 0000000000000000 ]---
>
>
>> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
>> index 65908880f424..ef32714cb182 100644
>> --- a/arch/x86/events/intel/ds.c
>> +++ b/arch/x86/events/intel/ds.c
>> @@ -2821,8 +2821,11 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs
>> *iregs, struct perf_sample_d
>> * If collision happened, the record will be dropped.
>> */
>> if (pebs_status != (1ULL << bit)) {
>> - for_each_set_bit(i, (unsigned long *)&pebs_status,
>> size)
>> + for_each_set_bit(i, (unsigned long *)&pebs_status,
>> size) {
>> error[i]++;
>> + if (error[i] && !events[i])
>> + events[i] = cpuc->events[i];
>> + }
>> continue;
>> }
>>
>>
>> On 9/8/2025 5:05 PM, Mi, Dapeng wrote:
>>> On 9/8/2025 4:43 PM, kernel test robot wrote:
>>>> Hello,
>>>>
>>>> kernel test robot noticed "WARNING:at_arch/x86/events/intel/ds.c:#intel_pmu_drain_pebs_nhm" on:
>>>>
>>>> commit: a7138973beb1d124386472663cf50a571a2059ce ("[Patch v7 02/12] perf/x86/intel: Fix NULL event access and potential PEBS record loss")
>>>> url: https://github.com/intel-lab-lkp/linux/commits/Dapeng-Mi/perf-x86-Remove-redundant-is_x86_event-prototype/20250828-094117
>>>> patch link: https://lore.kernel.org/all/20250828013435.1528459-3-dapeng1.mi@linux.intel.com/
>>>> patch subject: [Patch v7 02/12] perf/x86/intel: Fix NULL event access and potential PEBS record loss
>>>>
>>>> in testcase: phoronix-test-suite
>>>> version:
>>>> with following parameters:
>>>>
>>>> test: stress-ng-1.11.0
>>>> option_a: Socket Activity
>>>> cpufreq_governor: performance
>>>>
>>>>
>>>>
>>>> config: x86_64-rhel-9.4
>>>> compiler: gcc-12
>>>> test machine: 96 threads 2 sockets Intel(R) Xeon(R) Gold 6252 CPU @ 2.10GHz (Cascade Lake) with 512G memory
>>>>
>>>> (please refer to attached dmesg/kmsg for entire log/backtrace)
>>>>
>>>>
>>>>
>>>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
>>>> the same patch/commit), kindly add following tags
>>>> | Reported-by: kernel test robot <oliver.sang@...el.com>
>>>> | Closes: https://lore.kernel.org/oe-lkp/202509081646.d101cfb7-lkp@intel.com
>>>>
>>>>
>>>>
>>>> The kernel config and materials to reproduce are available at:
>>>> https://download.01.org/0day-ci/archive/20250908/202509081646.d101cfb7-lkp@intel.com
>>>>
>>>>
>>>> the dmesg in above link is not very clear, so we also attached one dmesg FYI,
>>>> from which:
>>>>
>>>> [ 41.225784][ C82] ------------[ cut here ]------------
>>>> [ 41.225786][ C82] WARNING: CPU: 82 PID: 3704 at arch/x86/events/intel/ds.c:2592 intel_pmu_drain_pebs_nhm+0x56b/0x630
>>>> [ 41.225791][ C82] Modules linked in: xt_conntrack nft_chain_nat xt_MASQUERADE nf_nat nf_conntrack_netlink nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
>>>> xt_addrtype nft_compat nf_tables nfnetlink br_netfilter bridge stp llc dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio qrtr sg binfmt_misc loop fus
>>>> e dm_mod overlay btrfs blake2b_generic xor raid6_pq intel_rapl_msr intel_rapl_common intel_uncore_frequency intel_uncore_frequency_common skx_edac skx_eda
>>>> c_common nfit libnvdimm x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irdma sd_mod ast irqbypass ice ipmi_ssif drm_client_lib snd_pcm ghash
>>>> _clmulni_intel drm_shmem_helper snd_timer gnss rapl drm_kms_helper intel_cstate snd ahci ib_uverbs libahci mei_me soundcore acpi_power_meter i2c_i801 ioat
>>>> dma drm ib_core pcspkr intel_uncore ipmi_si acpi_ipmi libata mei joydev i2c_smbus intel_pch_thermal lpc_ich dca wmi ipmi_devintf ipmi_msghandler acpi_pad
>>>> [ 41.225831][ C82] CPU: 82 UID: 0 PID: 3704 Comm: sleep Tainted: G S 6.17.0-rc1-00052-ga7138973beb1 #1 VOLUNTARY
>>>> [ 41.225834][ C82] Tainted: [S]=CPU_OUT_OF_SPEC
>>>> [ 41.225835][ C82] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
>>>> [ 41.225836][ C82] RIP: 0010:intel_pmu_drain_pebs_nhm+0x56b/0x630
>>>> [ 41.225839][ C82] Code: 48 e8 b9 cd fe ff 85 c0 0f 84 a9 00 00 00 41 f6 84 24 a4 01 00 00 80 0f 84 9a 00 00 00 4c 89 ef e8 1a 2a 34 00 e9 c7 fc ff ff
>>>> <0f> 0b e9 c0 fc ff ff 0f 0b e9 b9 fc ff ff 48 8b 04 cb 48 89 84 cc
>>>> [ 41.225841][ C82] RSP: 0018:fffffe00012f38c0 EFLAGS: 00010046
>>>> [ 41.225843][ C82] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
>>>> [ 41.225844][ C82] RDX: 0000000000000001 RSI: 0000000000000004 RDI: fffffe00012f3900
>>>> [ 41.225845][ C82] RBP: fffffe00013120c8 R08: 0000000000000000 R09: 0000000000000000
>>>> [ 20.931889][ T1340] Error: Driver 'pcspkr' is already registered, aborting...
>>>> [ 41.225846][ C82] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
>>>> [ 41.225847][ C82] R13: 0000000000000000 R14: fffffe00012f3c80 R15: 0000000000000000
>>>> [ 41.225848][ C82] FS: 0000000000000000(0000) GS:ffff88f027c62000(0000) knlGS:0000000000000000
>>>> [ 21.006859][ T1512] sd 6:0:0:0: Attached scsi generic sg0 type 0
>>>> [ 21.013583][ T1512] sd 7:0:0:0: Attached scsi generic sg1 type 0
>>>> [ 41.225849][ C82] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>> [ 41.225851][ C82] CR2: 00007ffe5571fe7c CR3: 00000040c5ae1003 CR4: 00000000007726f0
>>>> [ 41.225852][ C82] PKRU: 55555554
>>>> [ 41.225853][ C82] Call Trace:
>>>> [ 41.225855][ C82] <NMI>
>>>> [ 41.225861][ C82] handle_pmi_common+0x29b/0x430
>>>> [ 41.225865][ C82] intel_pmu_handle_irq+0x109/0x2b0
>>>> [ 41.225867][ C82] perf_event_nmi_handler+0x2a/0x70
>>>> [ 41.225870][ C82] nmi_handle+0x53/0x130
>>>> [ 41.225873][ C82] default_do_nmi+0x11d/0x170
>>>> [ 41.225876][ C82] exc_nmi+0x106/0x1b0
>>>> [ 41.225878][ C82] end_repeat_nmi+0xf/0x53
>>>> [ 41.225880][ C82] RIP: 0010:find_next_fd+0x2a/0xb0
>>>> [ 41.225883][ C82] Code: 0f 1f 44 00 00 41 54 89 f2 48 c7 c0 ff ff ff ff 49 89 fc 55 c1 ea 06 53 89 f3 48 8b 77 18 89 d9 48 d3 e0 48 f7 d0 48 0b 04 d6
>>>> <48> 83 f8 ff 74 0d 48 f7 d0 f3 48 0f bc c0 83 f8 3f 76 3a 41 8b 2c
>>>> [ 41.225885][ C82] RSP: 0018:ffffc90025283b90 EFLAGS: 00000206
>>>> [ 41.225886][ C82] RAX: 0000000000000017 RBX: 0000000000000003 RCX: 0000000000000003
>>>> [ 41.225887][ C82] RDX: 0000000000000000 RSI: ffff88f06d277150 RDI: ffff88f06d2770e8
>>>> [ 41.225888][ C82] RBP: 0000000000000400 R08: 8080808080808080 R09: 979c8d9e9a8cdfff
>>>> [ 41.225889][ C82] R10: fefefefefefefeff R11: 0000000000000000 R12: ffff88f06d2770e8
>>>> [ 41.225890][ C82] R13: 0000000000088000 R14: ffff88f06d2770c0 R15: ffff88f06d2770e8
>>>> [ 41.225893][ C82] ? find_next_fd+0x2a/0xb0
>>>> [ 41.225896][ C82] ? find_next_fd+0x2a/0xb0
>>>> [ 41.225899][ C82] </NMI>
>>>> [ 41.225899][ C82] <TASK>
>>>> [ 41.225900][ C82] alloc_fd+0x55/0x130
>>>> [ 41.225902][ C82] do_sys_openat2+0x5a/0xf0
>>>> [ 41.225905][ C82] __x64_sys_openat+0x6d/0xb0
>>>> [ 41.225907][ C82] do_syscall_64+0x7f/0x2b0
>>>> [ 41.225909][ C82] ? vfs_statx+0x68/0x170
>>>> [ 41.225911][ C82] ? strncpy_from_user+0x26/0xf0
>>>> [ 41.225914][ C82] ? vfs_fstatat+0x75/0xb0
>>>> [ 41.225917][ C82] ? __do_sys_newfstatat+0x25/0x70
>>>> [ 41.225919][ C82] ? path_openat+0xb6/0x2b0
>>>> [ 41.225921][ C82] ? do_syscall_64+0x7f/0x2b0
>>>> [ 41.225922][ C82] ? do_filp_open+0xc3/0x170
>>>> [ 41.225924][ C82] ? do_syscall_64+0x7f/0x2b0
>>>> [ 41.225925][ C82] ? __cond_resched+0x1e/0x70
>>>> [ 41.225928][ C82] ? check_heap_object+0x34/0x1b0
>>>> [ 41.225931][ C82] ? __check_object_size+0x5c/0x130
>>>> [ 41.225933][ C82] ? do_sys_openat2+0x8a/0xf0
>>>> [ 41.225936][ C82] ? __x64_sys_openat+0x6d/0xb0
>>>> [ 41.225938][ C82] ? clear_bhb_loop+0x30/0x80
>>>> [ 41.225940][ C82] ? clear_bhb_loop+0x30/0x80
>>>> [ 41.225942][ C82] entry_SYSCALL_64_after_hwframe+0x76/0x7e
>>>> [ 41.225944][ C82] RIP: 0033:0x7eff04bb9a2d
>>>> [ 41.225946][ C82] Code: 48 89 54 24 e0 41 83 e2 40 75 32 89 f0 25 00 00 41 00 3d 00 00 41 00 74 24 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05
>>>> <48> 3d 00 f0 ff ff 77 33 c3 66 2e 0f 1f 84 00 00 00 00 00 48 8d 44
>>>> [ 41.225947][ C82] RSP: 002b:00007ffe5571f7e8 EFLAGS: 00000287 ORIG_RAX: 0000000000000101
>>>> [ 41.225949][ C82] RAX: ffffffffffffffda RBX: 0000558b3236dbe6 RCX: 00007eff04bb9a2d
>>>> [ 41.225950][ C82] RDX: 0000000000080000 RSI: 00007eff04bc20b1 RDI: 00000000ffffff9c
>>>> [ 41.225951][ C82] RBP: 00007eff04bcd1f8 R08: 0000000000000000 R09: 0000558b3236dbe6
>>>> [ 41.225952][ C82] R10: 0000000000000000 R11: 0000000000000287 R12: ffffffffffffffff
>>>> [ 41.225953][ C82] R13: 0000000000000001 R14: 00007eff04bcc020 R15: 00007eff04bcd6b8
>>>> [ 41.225954][ C82] </TASK>
>>>> [ 41.225955][ C82] ---[ end trace 0000000000000000 ]---
>>>>
>>>>
>>> It looks the warning is triggered in the "error[i] != 0" case and lead to
>>> the local events[] array is not initialized. Would fix it in next version.
>>>
>>>
>>>
>>>
>> From 0afc076a7836433b455c8aff15d4a3ad9631ebc2 Mon Sep 17 00:00:00 2001
>> From: Dapeng Mi <dapeng1.mi@...ux.intel.com>
>> Date: Sun, 28 Sep 2025 13:50:47 +0800
>> Subject: [PATCH] perf/x86/intel: Fix NULL event access waring from test robot
>>
>> This patch fixes the warning about
>> https://lore.kernel.org/all/202509081646.d101cfb7-lkp@intel.com/.
>>
>> Signed-off-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>
>> ---
>> arch/x86/events/intel/ds.c | 5 ++++-
>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
>> index 65908880f424..ef32714cb182 100644
>> --- a/arch/x86/events/intel/ds.c
>> +++ b/arch/x86/events/intel/ds.c
>> @@ -2821,8 +2821,11 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_d
>> * If collision happened, the record will be dropped.
>> */
>> if (pebs_status != (1ULL << bit)) {
>> - for_each_set_bit(i, (unsigned long *)&pebs_status, size)
>> + for_each_set_bit(i, (unsigned long *)&pebs_status, size) {
>> error[i]++;
>> + if (error[i] && !events[i])
>> + events[i] = cpuc->events[i];
>> + }
>> continue;
>> }
>>
>> --
>> 2.34.1
>>
View attachment "0001-Fixup-perf-x86-intel-Fix-NULL-event-access-waring-fr.patch" of type "text/plain" (1578 bytes)
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