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author | Michael Ellerman <mpe@ellerman.id.au> | 2023-01-30 04:44:01 +0300 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-01-31 03:24:17 +0300 |
commit | ad53db4acb415976761d7302f5b02e97f2bd097e (patch) | |
tree | 94651b421855c91ca7fca2e1c620aa8d1405544d /arch/powerpc/kexec | |
parent | c28548012ee2bac55772ef7685138bd1124b80c3 (diff) | |
download | linux-ad53db4acb415976761d7302f5b02e97f2bd097e.tar.xz |
powerpc/imc-pmu: Revert nest_init_lock to being a mutex
The recent commit 76d588dddc45 ("powerpc/imc-pmu: Fix use of mutex in
IRQs disabled section") fixed warnings (and possible deadlocks) in the
IMC PMU driver by converting the locking to use spinlocks.
It also converted the init-time nest_init_lock to a spinlock, even
though it's not used at runtime in IRQ disabled sections or while
holding other spinlocks.
This leads to warnings such as:
BUG: sleeping function called from invalid context at include/linux/percpu-rwsem.h:49
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
preempt_count: 1, expected: 0
CPU: 7 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc2-14719-gf12cd06109f4-dirty #1
Hardware name: Mambo,Simulated-System POWER9 0x4e1203 opal:v6.6.6 PowerNV
Call Trace:
dump_stack_lvl+0x74/0xa8 (unreliable)
__might_resched+0x178/0x1a0
__cpuhp_setup_state+0x64/0x1e0
init_imc_pmu+0xe48/0x1250
opal_imc_counters_probe+0x30c/0x6a0
platform_probe+0x78/0x110
really_probe+0x104/0x420
__driver_probe_device+0xb0/0x170
driver_probe_device+0x58/0x180
__driver_attach+0xd8/0x250
bus_for_each_dev+0xb4/0x140
driver_attach+0x34/0x50
bus_add_driver+0x1e8/0x2d0
driver_register+0xb4/0x1c0
__platform_driver_register+0x38/0x50
opal_imc_driver_init+0x2c/0x40
do_one_initcall+0x80/0x360
kernel_init_freeable+0x310/0x3b8
kernel_init+0x30/0x1a0
ret_from_kernel_thread+0x5c/0x64
Fix it by converting nest_init_lock back to a mutex, so that we can call
sleeping functions while holding it. There is no interaction between
nest_init_lock and the runtime spinlocks used by the actual PMU routines.
Fixes: 76d588dddc45 ("powerpc/imc-pmu: Fix use of mutex in IRQs disabled section")
Tested-by: Kajol Jain<kjain@linux.ibm.com>
Reviewed-by: Kajol Jain<kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230130014401.540543-1-mpe@ellerman.id.au
Diffstat (limited to 'arch/powerpc/kexec')
0 files changed, 0 insertions, 0 deletions