Messages in this thread Patch in this message | | | From | Meng Li <> | Subject | [PATCH] mfd: altera-sysmgr: enable raw spinlock feature for preempt-rt kernel | Date | Tue, 16 Nov 2021 18:54:24 +0800 |
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When booting up preempt rt kernel on stratix10 platform, there is below calltrace: BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:969 in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 1, name: swapper/0 Preemption disabled at: [<ffff8000100b25b0>] __setup_irq+0xe0/0x730 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.78-rt54-yocto-preempt-rt #1 Hardware name: SoCFPGA Stratix 10 SoCDK (DT) Call trace: ...... ___might_sleep+0x144/0x180 rt_spin_lock+0x34/0x9c regmap_lock_spinlock+0x24/0x40 regmap_write+0x48/0x84 a10_eccmgr_irq_unmask+0x34/0x40 ...... altr_edac_a10_probe+0x16c/0x2b0 platform_drv_probe+0x60/0xb4 ...... ret_from_fork+0x10/0x38
Because regmap_write is invoked under preemption disabled status, and might trigger sleep. Recently, the commit 67021f25d952("regmap: teach regmap to use raw spinlocks if requested in the config ") add an option for regmap to use raw spinlock. So, enable raw spinlock in preempt-rt kernel to avoid the might sleep issue. Note: The commit 67021f25d952 is only in kernel v5.15, not included in earlier versions. So, if intend to fix this issue in earlier preempt-rt kernel, it is need to backport the 2 patches together, otherwise there will be building issue.
Signed-off-by: Meng Li <Meng.Li@windriver.com> ---
v2: - improve the patch title. - improve the commit log. Clear which commit is depended by this patch.
--- drivers/mfd/altera-sysmgr.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/mfd/altera-sysmgr.c b/drivers/mfd/altera-sysmgr.c index 5d3715a28b28..27271cec5d53 100644 --- a/drivers/mfd/altera-sysmgr.c +++ b/drivers/mfd/altera-sysmgr.c @@ -83,6 +83,9 @@ static struct regmap_config altr_sysmgr_regmap_cfg = { .fast_io = true, .use_single_read = true, .use_single_write = true, +#ifdef CONFIG_PREEMPT_RT + .use_raw_spinlock = true, +#endif }; /** -- 2.17.1
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