2023-09-27 20:07:35

by Joseph, Jithu

Subject: [PATCH 1/1] platform/x86/intel/ifs: release cpus_read_lock()

Couple of error paths in do_core_test() was returning directly without
doing a necessary cpus_read_unlock().

Following lockdep warning was observed when exercising these scenarios
with PROVE_RAW_LOCK_NESTING enabled:

[ 139.304775] ================================================
[ 139.311185] WARNING: lock held when returning to user space!
[ 139.317593] 6.6.0-rc2ifs01+ #11 Tainted: G S W I
[ 139.324499] ------------------------------------------------
[ 139.330908] bash/11476 is leaving the kernel with locks still held!
[ 139.338000] 1 lock held by bash/11476:
[ 139.342262] #0: ffffffffaa26c930 (cpu_hotplug_lock){++++}-{0:0}, at:
do_core_test+0x35/0x1c0 [intel_ifs]

Fix the flow so that all scenarios release the lock prior to returning
from the function.

Fixes: 5210fb4e1880 ("platform/x86/intel/ifs: Sysfs interface for Array BIST")
Cc: [email protected]
Signed-off-by: Jithu Joseph <[email protected]>
---
drivers/platform/x86/intel/ifs/runtest.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/intel/ifs/runtest.c b/drivers/platform/x86/intel/ifs/runtest.c
index 1061eb7ec399..43c864add778 100644
--- a/drivers/platform/x86/intel/ifs/runtest.c
+++ b/drivers/platform/x86/intel/ifs/runtest.c
@@ -331,14 +331,15 @@ int do_core_test(int cpu, struct device *dev)
switch (test->test_num) {
case IFS_TYPE_SAF:
if (!ifsd->loaded)
- return -EPERM;
- ifs_test_core(cpu, dev);
+ ret = -EPERM;
+ else
+ ifs_test_core(cpu, dev);
break;
case IFS_TYPE_ARRAY_BIST:
ifs_array_test_core(cpu, dev);
break;
default:
- return -EINVAL;
+ ret = -EINVAL;
}
out:
cpus_read_unlock();

base-commit: 6465e260f48790807eef06b583b38ca9789b6072
--
2.25.1

2023-10-04 09:57:18

by Hans de Goede

Subject: Re: [PATCH 1/1] platform/x86/intel/ifs: release cpus_read_lock()

Hi,

On 9/27/23 20:48, Jithu Joseph wrote:
> Couple of error paths in do_core_test() was returning directly without
> doing a necessary cpus_read_unlock().
>
> Following lockdep warning was observed when exercising these scenarios
> with PROVE_RAW_LOCK_NESTING enabled:
>
> [ 139.304775] ================================================
> [ 139.311185] WARNING: lock held when returning to user space!
> [ 139.317593] 6.6.0-rc2ifs01+ #11 Tainted: G S W I
> [ 139.324499] ------------------------------------------------
> [ 139.330908] bash/11476 is leaving the kernel with locks still held!
> [ 139.338000] 1 lock held by bash/11476:
> [ 139.342262] #0: ffffffffaa26c930 (cpu_hotplug_lock){++++}-{0:0}, at:
> do_core_test+0x35/0x1c0 [intel_ifs]
>
> Fix the flow so that all scenarios release the lock prior to returning
> from the function.
>
> Fixes: 5210fb4e1880 ("platform/x86/intel/ifs: Sysfs interface for Array BIST")
> Cc: [email protected]
> Signed-off-by: Jithu Joseph <[email protected]>

Thank you for your patch/series, I've applied this patch
(series) to the pdx86 fixes branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=fixes

Note it will show up in the pdx86 fixes branch once I've pushed
my local branch there, which might take a while.

I will include this patch in my next fixes pull-req to Linus
for the current kernel development cycle.

Regards,

Hans





> ---
> drivers/platform/x86/intel/ifs/runtest.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/platform/x86/intel/ifs/runtest.c b/drivers/platform/x86/intel/ifs/runtest.c
> index 1061eb7ec399..43c864add778 100644
> --- a/drivers/platform/x86/intel/ifs/runtest.c
> +++ b/drivers/platform/x86/intel/ifs/runtest.c
> @@ -331,14 +331,15 @@ int do_core_test(int cpu, struct device *dev)
> switch (test->test_num) {
> case IFS_TYPE_SAF:
> if (!ifsd->loaded)
> - return -EPERM;
> - ifs_test_core(cpu, dev);
> + ret = -EPERM;
> + else
> + ifs_test_core(cpu, dev);
> break;
> case IFS_TYPE_ARRAY_BIST:
> ifs_array_test_core(cpu, dev);
> break;
> default:
> - return -EINVAL;
> + ret = -EINVAL;
> }
> out:
> cpus_read_unlock();
>
> base-commit: 6465e260f48790807eef06b583b38ca9789b6072