* [PATCH] powerpc/papr_scm: don't requests stats with '0' sized stats buffer
@ 2022-05-24 11:23 ` Vaibhav Jain
0 siblings, 0 replies; 6+ messages in thread
From: Vaibhav Jain @ 2022-05-24 11:23 UTC (permalink / raw)
To: nvdimm, linuxppc-dev
Cc: Vaibhav Jain, Dan Williams, Aneesh Kumar K . V, Michael Ellerman,
Shivaprasad G Bhat, Sachin Sant
Sachin reported [1] that on a POWER-10 lpar he is seeing a kernel panic being
reported with vPMEM when papr_scm probe is being called. The panic is of the
form below and is observed only with following option disabled(profile) for the
said LPAR 'Enable Performance Information Collection' in the HMC:
Kernel attempted to write user page (1c) - exploit attempt? (uid: 0)
BUG: Kernel NULL pointer dereference on write at 0x0000001c
Faulting instruction address: 0xc008000001b90844
Oops: Kernel access of bad area, sig: 11 [#1]
<snip>
NIP [c008000001b90844] drc_pmem_query_stats+0x5c/0x270 [papr_scm]
LR [c008000001b92794] papr_scm_probe+0x2ac/0x6ec [papr_scm]
Call Trace:
0xc00000000941bca0 (unreliable)
papr_scm_probe+0x2ac/0x6ec [papr_scm]
platform_probe+0x98/0x150
really_probe+0xfc/0x510
__driver_probe_device+0x17c/0x230
<snip>
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Fatal exception
On investigation looks like this panic was caused due to a 'stat_buffer' of
size==0 being provided to drc_pmem_query_stats() to fetch all performance
stats-ids of an NVDIMM. However drc_pmem_query_stats() shouldn't have been called
since the vPMEM NVDIMM doesn't support and performance stat-id's. This was caused
due to missing check for 'p->stat_buffer_len' at the beginning of
papr_scm_pmu_check_events() which indicates that the NVDIMM doesn't support
performance-stats.
Fix this by introducing the check for 'p->stat_buffer_len' at the beginning of
papr_scm_pmu_check_events().
[1] https://lore.kernel.org/all/6B3A522A-6A5F-4CC9-B268-0C63AA6E07D3@linux.ibm.com
Fixes: 0e0946e22f3665d2732 ("powerpc/papr_scm: Fix leaking nvdimm_events_map elements")
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
arch/powerpc/platforms/pseries/papr_scm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 181b855b3050..82cae08976bc 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -465,6 +465,9 @@ static int papr_scm_pmu_check_events(struct papr_scm_priv *p, struct nvdimm_pmu
u32 available_events;
int index, rc = 0;
+ if (!p->stat_buffer_len)
+ return -ENOENT;
+
available_events = (p->stat_buffer_len - sizeof(struct papr_scm_perf_stats))
/ sizeof(struct papr_scm_perf_stat);
if (available_events == 0)
--
2.35.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] powerpc/papr_scm: don't requests stats with '0' sized stats buffer
@ 2022-05-24 11:23 ` Vaibhav Jain
0 siblings, 0 replies; 6+ messages in thread
From: Vaibhav Jain @ 2022-05-24 11:23 UTC (permalink / raw)
To: nvdimm, linuxppc-dev
Cc: Shivaprasad G Bhat, Sachin Sant, Aneesh Kumar K . V,
Vaibhav Jain, Dan Williams
Sachin reported [1] that on a POWER-10 lpar he is seeing a kernel panic being
reported with vPMEM when papr_scm probe is being called. The panic is of the
form below and is observed only with following option disabled(profile) for the
said LPAR 'Enable Performance Information Collection' in the HMC:
Kernel attempted to write user page (1c) - exploit attempt? (uid: 0)
BUG: Kernel NULL pointer dereference on write at 0x0000001c
Faulting instruction address: 0xc008000001b90844
Oops: Kernel access of bad area, sig: 11 [#1]
<snip>
NIP [c008000001b90844] drc_pmem_query_stats+0x5c/0x270 [papr_scm]
LR [c008000001b92794] papr_scm_probe+0x2ac/0x6ec [papr_scm]
Call Trace:
0xc00000000941bca0 (unreliable)
papr_scm_probe+0x2ac/0x6ec [papr_scm]
platform_probe+0x98/0x150
really_probe+0xfc/0x510
__driver_probe_device+0x17c/0x230
<snip>
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Fatal exception
On investigation looks like this panic was caused due to a 'stat_buffer' of
size==0 being provided to drc_pmem_query_stats() to fetch all performance
stats-ids of an NVDIMM. However drc_pmem_query_stats() shouldn't have been called
since the vPMEM NVDIMM doesn't support and performance stat-id's. This was caused
due to missing check for 'p->stat_buffer_len' at the beginning of
papr_scm_pmu_check_events() which indicates that the NVDIMM doesn't support
performance-stats.
Fix this by introducing the check for 'p->stat_buffer_len' at the beginning of
papr_scm_pmu_check_events().
[1] https://lore.kernel.org/all/6B3A522A-6A5F-4CC9-B268-0C63AA6E07D3@linux.ibm.com
Fixes: 0e0946e22f3665d2732 ("powerpc/papr_scm: Fix leaking nvdimm_events_map elements")
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
arch/powerpc/platforms/pseries/papr_scm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 181b855b3050..82cae08976bc 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -465,6 +465,9 @@ static int papr_scm_pmu_check_events(struct papr_scm_priv *p, struct nvdimm_pmu
u32 available_events;
int index, rc = 0;
+ if (!p->stat_buffer_len)
+ return -ENOENT;
+
available_events = (p->stat_buffer_len - sizeof(struct papr_scm_perf_stats))
/ sizeof(struct papr_scm_perf_stat);
if (available_events == 0)
--
2.35.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc/papr_scm: don't requests stats with '0' sized stats buffer
2022-05-24 11:23 ` Vaibhav Jain
@ 2022-05-24 13:51 ` Sachin Sant
-1 siblings, 0 replies; 6+ messages in thread
From: Sachin Sant @ 2022-05-24 13:51 UTC (permalink / raw)
To: Vaibhav Jain
Cc: nvdimm, linuxppc-dev, Dan Williams, Aneesh Kumar K . V,
Michael Ellerman, Shivaprasad G Bhat
> On 24-May-2022, at 4:53 PM, Vaibhav Jain <vaibhav@linux.ibm.com> wrote:
>
> Sachin reported [1] that on a POWER-10 lpar he is seeing a kernel panic being
> reported with vPMEM when papr_scm probe is being called. The panic is of the
> form below and is observed only with following option disabled(profile) for the
> said LPAR 'Enable Performance Information Collection' in the HMC:
>
> Kernel attempted to write user page (1c) - exploit attempt? (uid: 0)
> BUG: Kernel NULL pointer dereference on write at 0x0000001c
> Faulting instruction address: 0xc008000001b90844
> Oops: Kernel access of bad area, sig: 11 [#1]
> <snip>
> NIP [c008000001b90844] drc_pmem_query_stats+0x5c/0x270 [papr_scm]
> LR [c008000001b92794] papr_scm_probe+0x2ac/0x6ec [papr_scm]
> Call Trace:
> 0xc00000000941bca0 (unreliable)
> papr_scm_probe+0x2ac/0x6ec [papr_scm]
> platform_probe+0x98/0x150
> really_probe+0xfc/0x510
> __driver_probe_device+0x17c/0x230
> <snip>
> ---[ end trace 0000000000000000 ]---
> Kernel panic - not syncing: Fatal exception
>
> On investigation looks like this panic was caused due to a 'stat_buffer' of
> size==0 being provided to drc_pmem_query_stats() to fetch all performance
> stats-ids of an NVDIMM. However drc_pmem_query_stats() shouldn't have been called
> since the vPMEM NVDIMM doesn't support and performance stat-id's. This was caused
> due to missing check for 'p->stat_buffer_len' at the beginning of
> papr_scm_pmu_check_events() which indicates that the NVDIMM doesn't support
> performance-stats.
>
> Fix this by introducing the check for 'p->stat_buffer_len' at the beginning of
> papr_scm_pmu_check_events().
>
> [1] https://lore.kernel.org/all/6B3A522A-6A5F-4CC9-B268-0C63AA6E07D3@linux.ibm.com
>
> Fixes: 0e0946e22f3665d2732 ("powerpc/papr_scm: Fix leaking nvdimm_events_map elements")
> Reported-by: Sachin Sant <sachinp@linux.ibm.com>
> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
> ---
Thanks Vaibhav for the patch. With the patch the reported problem is fixed.
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
-Sachin
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc/papr_scm: don't requests stats with '0' sized stats buffer
@ 2022-05-24 13:51 ` Sachin Sant
0 siblings, 0 replies; 6+ messages in thread
From: Sachin Sant @ 2022-05-24 13:51 UTC (permalink / raw)
To: Vaibhav Jain
Cc: nvdimm, Shivaprasad G Bhat, Aneesh Kumar K . V, Dan Williams,
linuxppc-dev
> On 24-May-2022, at 4:53 PM, Vaibhav Jain <vaibhav@linux.ibm.com> wrote:
>
> Sachin reported [1] that on a POWER-10 lpar he is seeing a kernel panic being
> reported with vPMEM when papr_scm probe is being called. The panic is of the
> form below and is observed only with following option disabled(profile) for the
> said LPAR 'Enable Performance Information Collection' in the HMC:
>
> Kernel attempted to write user page (1c) - exploit attempt? (uid: 0)
> BUG: Kernel NULL pointer dereference on write at 0x0000001c
> Faulting instruction address: 0xc008000001b90844
> Oops: Kernel access of bad area, sig: 11 [#1]
> <snip>
> NIP [c008000001b90844] drc_pmem_query_stats+0x5c/0x270 [papr_scm]
> LR [c008000001b92794] papr_scm_probe+0x2ac/0x6ec [papr_scm]
> Call Trace:
> 0xc00000000941bca0 (unreliable)
> papr_scm_probe+0x2ac/0x6ec [papr_scm]
> platform_probe+0x98/0x150
> really_probe+0xfc/0x510
> __driver_probe_device+0x17c/0x230
> <snip>
> ---[ end trace 0000000000000000 ]---
> Kernel panic - not syncing: Fatal exception
>
> On investigation looks like this panic was caused due to a 'stat_buffer' of
> size==0 being provided to drc_pmem_query_stats() to fetch all performance
> stats-ids of an NVDIMM. However drc_pmem_query_stats() shouldn't have been called
> since the vPMEM NVDIMM doesn't support and performance stat-id's. This was caused
> due to missing check for 'p->stat_buffer_len' at the beginning of
> papr_scm_pmu_check_events() which indicates that the NVDIMM doesn't support
> performance-stats.
>
> Fix this by introducing the check for 'p->stat_buffer_len' at the beginning of
> papr_scm_pmu_check_events().
>
> [1] https://lore.kernel.org/all/6B3A522A-6A5F-4CC9-B268-0C63AA6E07D3@linux.ibm.com
>
> Fixes: 0e0946e22f3665d2732 ("powerpc/papr_scm: Fix leaking nvdimm_events_map elements")
> Reported-by: Sachin Sant <sachinp@linux.ibm.com>
> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
> ---
Thanks Vaibhav for the patch. With the patch the reported problem is fixed.
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
-Sachin
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc/papr_scm: don't requests stats with '0' sized stats buffer
2022-05-24 11:23 ` Vaibhav Jain
@ 2022-06-09 14:44 ` Michael Ellerman
-1 siblings, 0 replies; 6+ messages in thread
From: Michael Ellerman @ 2022-06-09 14:44 UTC (permalink / raw)
To: linuxppc-dev, Vaibhav Jain, nvdimm
Cc: Michael Ellerman, Dan Williams, Aneesh Kumar K . V, Sachin Sant,
Shivaprasad G Bhat
On Tue, 24 May 2022 16:53:53 +0530, Vaibhav Jain wrote:
> Sachin reported [1] that on a POWER-10 lpar he is seeing a kernel panic being
> reported with vPMEM when papr_scm probe is being called. The panic is of the
> form below and is observed only with following option disabled(profile) for the
> said LPAR 'Enable Performance Information Collection' in the HMC:
>
> Kernel attempted to write user page (1c) - exploit attempt? (uid: 0)
> BUG: Kernel NULL pointer dereference on write at 0x0000001c
> Faulting instruction address: 0xc008000001b90844
> Oops: Kernel access of bad area, sig: 11 [#1]
> <snip>
> NIP [c008000001b90844] drc_pmem_query_stats+0x5c/0x270 [papr_scm]
> LR [c008000001b92794] papr_scm_probe+0x2ac/0x6ec [papr_scm]
> Call Trace:
> 0xc00000000941bca0 (unreliable)
> papr_scm_probe+0x2ac/0x6ec [papr_scm]
> platform_probe+0x98/0x150
> really_probe+0xfc/0x510
> __driver_probe_device+0x17c/0x230
> <snip>
> ---[ end trace 0000000000000000 ]---
> Kernel panic - not syncing: Fatal exception
>
> [...]
Applied to powerpc/fixes.
[1/1] powerpc/papr_scm: don't requests stats with '0' sized stats buffer
https://git.kernel.org/powerpc/c/07bf9431b1590d1cd7a8d62075d0b50b073f0495
cheers
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] powerpc/papr_scm: don't requests stats with '0' sized stats buffer
@ 2022-06-09 14:44 ` Michael Ellerman
0 siblings, 0 replies; 6+ messages in thread
From: Michael Ellerman @ 2022-06-09 14:44 UTC (permalink / raw)
To: linuxppc-dev, Vaibhav Jain, nvdimm
Cc: Dan Williams, Shivaprasad G Bhat, Sachin Sant, Aneesh Kumar K . V
On Tue, 24 May 2022 16:53:53 +0530, Vaibhav Jain wrote:
> Sachin reported [1] that on a POWER-10 lpar he is seeing a kernel panic being
> reported with vPMEM when papr_scm probe is being called. The panic is of the
> form below and is observed only with following option disabled(profile) for the
> said LPAR 'Enable Performance Information Collection' in the HMC:
>
> Kernel attempted to write user page (1c) - exploit attempt? (uid: 0)
> BUG: Kernel NULL pointer dereference on write at 0x0000001c
> Faulting instruction address: 0xc008000001b90844
> Oops: Kernel access of bad area, sig: 11 [#1]
> <snip>
> NIP [c008000001b90844] drc_pmem_query_stats+0x5c/0x270 [papr_scm]
> LR [c008000001b92794] papr_scm_probe+0x2ac/0x6ec [papr_scm]
> Call Trace:
> 0xc00000000941bca0 (unreliable)
> papr_scm_probe+0x2ac/0x6ec [papr_scm]
> platform_probe+0x98/0x150
> really_probe+0xfc/0x510
> __driver_probe_device+0x17c/0x230
> <snip>
> ---[ end trace 0000000000000000 ]---
> Kernel panic - not syncing: Fatal exception
>
> [...]
Applied to powerpc/fixes.
[1/1] powerpc/papr_scm: don't requests stats with '0' sized stats buffer
https://git.kernel.org/powerpc/c/07bf9431b1590d1cd7a8d62075d0b50b073f0495
cheers
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-06-09 14:48 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2022-05-24 11:23 [PATCH] powerpc/papr_scm: don't requests stats with '0' sized stats buffer Vaibhav Jain
2022-05-24 11:23 ` Vaibhav Jain
2022-05-24 13:51 ` Sachin Sant
2022-05-24 13:51 ` Sachin Sant
2022-06-09 14:44 ` Michael Ellerman
2022-06-09 14:44 ` Michael Ellerman
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