[PATCH] perf/x86/intel/uncore: Avoid null dereferences (uncore_extra_pci_dev)

[PATCH] perf/x86/intel/uncore: Avoid null dereferences (uncore_extra_pci_dev)

[Steve Wahl]

If an uncore has no pci_init routine, or that routine fails,
uncore_pci_init is not called, and memory is not allocated for
uncore_extra_pci_dev.

So check to make sure uncore_extra_pci_dev is not NULL before use.

And fix the case that led us to discover the null derefs; don't fail
snbep_pci2phy_map_init if BIOS doesn't supply pcibus_to_node
information.

Fixes: 9a7832ce3d92 ("perf/x86/intel/uncore: With > 8 nodes, get pci bus die id from NUMA info")

Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
---
 arch/x86/events/intel/uncore_snbep.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index b79951d0707c..14c24356a2fa 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -1373,11 +1373,11 @@ static int snbep_pci2phy_map_init(int devid, int nodeid_loc, int idmap_loc, bool
 		/*
 		 * The nodeid and idmap registers only contain enough
 		 * information to handle 8 nodes.  On systems with more
-		 * than 8 nodes, we need to rely on NUMA information,
+		 * than 8 nodes, if available we rely on NUMA information,
 		 * filled in from BIOS supplied information, to determine
 		 * the topology.
 		 */
-		if (nr_node_ids <= 8) {
+		if ((nr_node_ids <= 8) || (pcibus_to_node(ubox_dev->bus) == -1)) {
 			/* get the Node ID of the local register */
 			err = pci_read_config_dword(ubox_dev, nodeid_loc, &config);
 			if (err)
@@ -2865,7 +2865,9 @@ void hswep_uncore_cpu_init(void)
 		hswep_uncore_cbox.num_boxes = boot_cpu_data.x86_max_cores;
 
 	/* Detect 6-8 core systems with only two SBOXes */
-	if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
+	if (!uncore_extra_pci_dev)
+		hswep_uncore_sbox.num_boxes = 2;
+	else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
 		u32 capid4;
 
 		pci_read_config_dword(uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3],
@@ -3243,6 +3245,8 @@ void bdx_uncore_cpu_init(void)
 	if (boot_cpu_data.x86_model == 86) {
 		uncore_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
 	/* Detect systems with no SBOXes */
+	} else if (!uncore_extra_pci_dev) {
+		bdx_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
 	} else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
 		struct pci_dev *pdev;
 		u32 capid4;
-- 
2.26.2

Re: [PATCH] perf/x86/intel/uncore: Avoid null dereferences (uncore_extra_pci_dev)

[Liang, Kan]

Hi Steve,

On 4/15/2021 4:37 PM, Steve Wahl wrote:
> If an uncore has no pci_init routine, or that routine fails,
> uncore_pci_init is not called, and memory is not allocated for
> uncore_extra_pci_dev.
> 
> So check to make sure uncore_extra_pci_dev is not NULL before use.
>

I think more after yesterday's discussion. There may be a better 
solution than this.

Actually, we don't have to probe all the PCU devices and stores them 
into the uncore_extra_pci_dev for the cpu_init().
We just need to pick up the first PCU device and check the existence of 
the SBOX once.

I will send out a patch shortly.

> And fix the case that led us to discover the null derefs; don't fail
> snbep_pci2phy_map_init if BIOS doesn't supply pcibus_to_node
> information.
> 
> Fixes: 9a7832ce3d92 ("perf/x86/intel/uncore: With > 8 nodes, get pci bus die id from NUMA info")

In theory, the pci_read_config_dword() may fails as well. It has 
possible that the issue can still be observed before the "> 8 nodes" patch.

I think the fixes should be 5306c31c5733 ("perf/x86/uncore/hsw-ep: 
Handle systems with only two SBOXes")

Thanks,
Kan

> Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
> ---
>   arch/x86/events/intel/uncore_snbep.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
> index b79951d0707c..14c24356a2fa 100644
> --- a/arch/x86/events/intel/uncore_snbep.c
> +++ b/arch/x86/events/intel/uncore_snbep.c
> @@ -1373,11 +1373,11 @@ static int snbep_pci2phy_map_init(int devid, int nodeid_loc, int idmap_loc, bool
>   		/*
>   		 * The nodeid and idmap registers only contain enough
>   		 * information to handle 8 nodes.  On systems with more
> -		 * than 8 nodes, we need to rely on NUMA information,
> +		 * than 8 nodes, if available we rely on NUMA information,
>   		 * filled in from BIOS supplied information, to determine
>   		 * the topology.
>   		 */
> -		if (nr_node_ids <= 8) {
> +		if ((nr_node_ids <= 8) || (pcibus_to_node(ubox_dev->bus) == -1)) {
>   			/* get the Node ID of the local register */
>   			err = pci_read_config_dword(ubox_dev, nodeid_loc, &config);
>   			if (err)
> @@ -2865,7 +2865,9 @@ void hswep_uncore_cpu_init(void)
>   		hswep_uncore_cbox.num_boxes = boot_cpu_data.x86_max_cores;
>   
>   	/* Detect 6-8 core systems with only two SBOXes */
> -	if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
> +	if (!uncore_extra_pci_dev)
> +		hswep_uncore_sbox.num_boxes = 2;
> +	else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
>   		u32 capid4;
>   
>   		pci_read_config_dword(uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3],
> @@ -3243,6 +3245,8 @@ void bdx_uncore_cpu_init(void)
>   	if (boot_cpu_data.x86_model == 86) {
>   		uncore_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
>   	/* Detect systems with no SBOXes */
> +	} else if (!uncore_extra_pci_dev) {
> +		bdx_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
>   	} else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
>   		struct pci_dev *pdev;
>   		u32 capid4;
> 

Re: [PATCH] perf/x86/intel/uncore: Avoid null dereferences (uncore_extra_pci_dev)

[Liang, Kan]

On 4/15/2021 5:19 PM, Liang, Kan wrote:
> Hi Steve,
> 
> On 4/15/2021 4:37 PM, Steve Wahl wrote:
>> If an uncore has no pci_init routine, or that routine fails,
>> uncore_pci_init is not called, and memory is not allocated for
>> uncore_extra_pci_dev.
>>
>> So check to make sure uncore_extra_pci_dev is not NULL before use.
>>
> 
> I think more after yesterday's discussion. There may be a better 
> solution than this.
> 
> Actually, we don't have to probe all the PCU devices and stores them 
> into the uncore_extra_pci_dev for the cpu_init().
> We just need to pick up the first PCU device and check the existence of 
> the SBOX once.
> 
> I will send out a patch shortly.

Here is the patch I mentioned.

https://lore.kernel.org/lkml/1618521764-100923-1-git-send-email-kan.liang@linux.intel.com

Thanks,
Kan

> 
>> And fix the case that led us to discover the null derefs; don't fail
>> snbep_pci2phy_map_init if BIOS doesn't supply pcibus_to_node
>> information.
>>
>> Fixes: 9a7832ce3d92 ("perf/x86/intel/uncore: With > 8 nodes, get pci 
>> bus die id from NUMA info")
> 
> In theory, the pci_read_config_dword() may fails as well. It has 
> possible that the issue can still be observed before the "> 8 nodes" patch.
> 
> I think the fixes should be 5306c31c5733 ("perf/x86/uncore/hsw-ep: 
> Handle systems with only two SBOXes")
> 
> Thanks,
> Kan
> 
>> Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
>> ---
>>   arch/x86/events/intel/uncore_snbep.c | 10 +++++++---
>>   1 file changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/events/intel/uncore_snbep.c 
>> b/arch/x86/events/intel/uncore_snbep.c
>> index b79951d0707c..14c24356a2fa 100644
>> --- a/arch/x86/events/intel/uncore_snbep.c
>> +++ b/arch/x86/events/intel/uncore_snbep.c
>> @@ -1373,11 +1373,11 @@ static int snbep_pci2phy_map_init(int devid, 
>> int nodeid_loc, int idmap_loc, bool
>>           /*
>>            * The nodeid and idmap registers only contain enough
>>            * information to handle 8 nodes.  On systems with more
>> -         * than 8 nodes, we need to rely on NUMA information,
>> +         * than 8 nodes, if available we rely on NUMA information,
>>            * filled in from BIOS supplied information, to determine
>>            * the topology.
>>            */
>> -        if (nr_node_ids <= 8) {
>> +        if ((nr_node_ids <= 8) || (pcibus_to_node(ubox_dev->bus) == 
>> -1)) {
>>               /* get the Node ID of the local register */
>>               err = pci_read_config_dword(ubox_dev, nodeid_loc, &config);
>>               if (err)
>> @@ -2865,7 +2865,9 @@ void hswep_uncore_cpu_init(void)
>>           hswep_uncore_cbox.num_boxes = boot_cpu_data.x86_max_cores;
>>       /* Detect 6-8 core systems with only two SBOXes */
>> -    if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
>> +    if (!uncore_extra_pci_dev)
>> +        hswep_uncore_sbox.num_boxes = 2;
>> +    else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
>>           u32 capid4;
>>           
>> pci_read_config_dword(uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3],
>> @@ -3243,6 +3245,8 @@ void bdx_uncore_cpu_init(void)
>>       if (boot_cpu_data.x86_model == 86) {
>>           uncore_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
>>       /* Detect systems with no SBOXes */
>> +    } else if (!uncore_extra_pci_dev) {
>> +        bdx_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
>>       } else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
>>           struct pci_dev *pdev;
>>           u32 capid4;
>>