Messages in this thread | | | Date | Mon, 20 Oct 2014 17:38:53 -0400 | From | Peter Hurley <> | Subject | Re: [PATCH] tty: serial: msm: Fix lock init issue with earlycon |
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On 10/20/2014 02:27 PM, Stephen Boyd wrote: > On 10/17/2014 06:13 AM, Kumar Gala wrote: >> With CONFIG_DEBUG_SPINLOCK enabled we see: >> >> BUG: spinlock bad magic on CPU#0, swapper/0 >> lock: early_console_dev+0x8/0x160, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0 >> CPU: 0 PID: 0 Comm: swapper Not tainted 3.17.0-09733-gb446b33-dirty #18 > > [...] > >> diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c >> index 4b6c783..8ab27c9 100644 >> --- a/drivers/tty/serial/msm_serial.c >> +++ b/drivers/tty/serial/msm_serial.c >> @@ -973,6 +973,8 @@ msm_serial_early_console_setup(struct earlycon_device *device, const char *opt) >> if (!device->port.membase) >> return -ENODEV; >> + spin_lock_init(&device->port.lock); >> + >> device->con->write = msm_serial_early_write; >> return 0; >> } >> @@ -995,6 +997,8 @@ msm_serial_early_console_setup_dm(struct earlycon_device *device, >> if (!device->port.membase) >> return -ENODEV; >> + spin_lock_init(&device->port.lock); >> + >> device->con->write = msm_serial_early_write_dm; >> return 0; >> } > > Could this be done in the tty core instead?
Or even better: refactor __msm_console_write() so no spin_lock() is required for the earlycon write.
FWIW, __msm_console_write() is a deadlock-waiting-to_happen since it does not disable interrupts with spin_lock_irqsave().
Regards, Peter Hurley
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