Messages in this thread | | | Date | Thu, 8 Mar 2012 10:29:13 +0100 | From | Uwe Kleine-König <> | Subject | Re: [PATCH 2/3] led-triggers: use atomic kzalloc during led trigger registering |
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On Thu, Mar 08, 2012 at 05:11:02PM +0800, Bryan Wu wrote: > kzalloc might cause sleep and will generate some warning detected by lockdep, > when call led_trigger_register_simple on each cpu cores in SMP. This patch fix > this. The obvious (and IMHO better) alternative is to call led_trigger_register_simple from non-atomic context.
For registering this should be OK, shouldn't it?
Best regards Uwe
> > [ 1.999938] ------------[ cut here ]------------ > [ 2.004791] WARNING: at kernel/lockdep.c:2664 lockdep_trace_alloc+0xd8/0xf0() > [ 2.012298] Modules linked in: > [ 2.015563] [<c001b0cc>] (unwind_backtrace+0x0/0xf0) from [<c0052408>] (warn_slowpath_common+0x4c/0x64) > [ 2.025451] [<c0052408>] (warn_slowpath_common+0x4c/0x64) from [<c005243c>] (warn_slowpath_null+0x1c/0x24) > [ 2.035583] [<c005243c>] (warn_slowpath_null+0x1c/0x24) from [<c008be28>] (lockdep_trace_alloc+0xd8/0xf0) > [ 2.045684] [<c008be28>] (lockdep_trace_alloc+0xd8/0xf0) from [<c00feeb4>] (kmem_cache_alloc_trace+0x2c/0x148) > [ 2.056213] [<c00feeb4>] (kmem_cache_alloc_trace+0x2c/0x148) from [<c03770a0>] (led_trigger_register_simple+0x20/0x74) > [ 2.067474] [<c03770a0>] (led_trigger_register_simple+0x20/0x74) from [<c0627a30>] (ledtrig_cpu_register+0x4c/0x8c) > [ 2.078460] [<c0627a30>] (ledtrig_cpu_register+0x4c/0x8c) from [<c0094ca4>] (generic_smp_call_function_single_interrupt+0xcc/0x138) > [ 2.090911] [<c0094ca4>] (generic_smp_call_function_single_interrupt+0xcc/0x138) from [<c0008408>] (do_IPI+0xb0/0x128) > [ 2.102172] [<c0008408>] (do_IPI+0xb0/0x128) from [<c045921c>] (__irq_svc+0x3c/0x100) > [ 2.110412] Exception stack(0xc07adf70 to 0xc07adfb8) > [ 2.115722] df60: c07c80f8 0000fb45 00000000 c07c80f8 > [ 2.124328] df80: c07ac000 c0837be4 c0464b64 c07c9d8c 00000000 411fc092 00000000 00000000 > [ 2.132934] dfa0: c0649760 c07adfb8 c07c5c58 c0014d50 20000013 ffffffff > [ 2.139892] [<c045921c>] (__irq_svc+0x3c/0x100) from [<c0014d50>] (default_idle+0x30/0x38) > [ 2.148590] [<c0014d50>] (default_idle+0x30/0x38) from [<c0014f74>] (cpu_idle+0xb4/0xf4) > [ 2.157135] [<c0014f74>] (cpu_idle+0xb4/0xf4) from [<c0602778>] (start_kernel+0x2a8/0x2fc) > [ 2.165832] [<c0602778>] (start_kernel+0x2a8/0x2fc) from [<80008040>] (0x80008040) > [ 2.173797] ---[ end trace 97549d21d8dad3f5 ]--- > > Signed-off-by: Bryan Wu <bryan.wu@canonical.com> > --- > drivers/leds/led-triggers.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c > index 46b4c76..74d0ba7 100644 > --- a/drivers/leds/led-triggers.c > +++ b/drivers/leds/led-triggers.c > @@ -255,7 +255,7 @@ void led_trigger_register_simple(const char *name, struct led_trigger **tp) > struct led_trigger *trigger; > int err; > > - trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL); > + trigger = kzalloc(sizeof(struct led_trigger), GFP_ATOMIC); > > if (trigger) { > trigger->name = name; > -- > 1.7.9 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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