Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
coresight: cti: Fix hang in cti_disable_hw()
cti_enable_hw() and cti_disable_hw() are called from an atomic context so shouldn’t use runtime PM because it can result in a sleep when communicating with firmware.
Since commit 3c6656337852 (“Revert “firmware: arm_scmi: Add clock management to the SCMI power domain””), this causes a hang on Juno when running the Perf Coresight tests or running this command:
perf record -e cs_etm//u – ls
This was also missed until the revert commit because pm_runtime_put() was called with the wrong device until commit 692c9a499b28 (“coresight: cti: Correct the parameter for pm_runtime_put”)
With lock and scheduler debugging enabled the following is output:
coresight cti_sys0: cti_enable_hw – dev:cti_sys0 parent: 20020000.cti
BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:1151
in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 330, name: perf-exec
preempt_count: 2, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [
Fix the issue by removing the runtime PM calls completely. They are not needed here because it must have already been done when building the path for a trace.
[ Fix build warnings ]
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 5.14.0 (+1 more)
In the Linux kernel, the following vulnerability has been resolved:
coresight: cti: Fix hang in cti_disable_hw()
cti_enable_hw() and cti_disable_hw() are called from an atomic context so shouldn’t use runtime PM because it can result in a sleep when communicating with firmware.
Since commit 3c6656337852 (“Revert “firmware: arm_scmi: Add clock management to the SCMI power domain””), this causes a hang on Juno when running the Perf Coresight tests or running this command:
perf record -e cs_etm//u – ls
This was also missed until the revert commit because pm_runtime_put() was called with the wrong device until commit 692c9a499b28 (“coresight: cti: Correct the parameter for pm_runtime_put”)
With lock and scheduler debugging enabled the following is output:
coresight cti_sys0: cti_enable_hw – dev:cti_sys0 parent: 20020000.cti
BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:1151
in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 330, name: perf-exec
preempt_count: 2, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [
Fix the issue by removing the runtime PM calls completely. They are not needed here because it must have already been done when building the path for a trace.
[ Fix build warnings ]