[alsa-devel] [PATCH 2/5] ASoC: rsnd: make sure it uses lock when it calls rsnd_dai_call

[Geert Uytterhoeven]

	Hi Morimoto-san,

On Fri, 10 Apr 2015, Kuninori Morimoto wrote:
> From: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
> 
> rsnd_dai_call() should be called under rsnd_lock

Always? Why?

> @@ -949,8 +956,11 @@ static const struct snd_soc_component_driver rsnd_soc_component = {
>  static int rsnd_rdai_continuance_probe(struct rsnd_priv *priv,
>  				       struct rsnd_dai_stream *io)
>  {
> +	unsigned long flags;
>  	int ret;
>  
> +	rsnd_lock(priv, flags);
> +
>  	ret = rsnd_dai_call(probe, io, priv);
>  	if (ret == -EAGAIN) {
>  		/*

This causes the following warning on r8a7791/koelsch:

WARNING: CPU: 1 PID: 1 at kernel/locking/lockdep.c:2755 lockdep_trace_alloc+0xd4/0x118()
DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
Modules linked in:

CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.1.0-rc2-koelsch-00564-g1817f2746e13e08e #1081
Hardware name: Generic R8A7791 (Flattened Device Tree)
Backtrace: 
[<c00135e0>] (dump_backtrace) from [<c0013800>] (show_stack+0x18/0x1c)
 r6:c0546ece r5:00000009 r4:00000000 r3:00204140
[<c00137e8>] (show_stack) from [<c04483ec>] (dump_stack+0x78/0x94)
[<c0448374>] (dump_stack) from [<c002d368>] (warn_slowpath_common+0x90/0xbc)
 r4:eec59c90 r3:00000001
[<c002d2d8>] (warn_slowpath_common) from [<c002d3cc>] (warn_slowpath_fmt+0x38/0x40)
 r8:eed90010 r7:000001a1 r6:000080d0 r5:000080d0 r4:60000193
[<c002d398>] (warn_slowpath_fmt) from [<c0069e94>] (lockdep_trace_alloc+0xd4/0x118)
 r3:c054c535 r2:c0547435
[<c0069dc0>] (lockdep_trace_alloc) from [<c00e3acc>] (__kmalloc_track_caller+0x34/0x11c)
 r5:eec000c0 r4:00000000
[<c00e3a98>] (__kmalloc_track_caller) from [<c02678b4>] (devres_alloc+0x20/0x48)
 r7:000001a1 r6:ee7e2138 r5:c007a3d8 r4:00000000
[<c0267894>] (devres_alloc) from [<c007a378>] (devm_request_threaded_irq+0x34/0x94)
 r5:ee7ea8d0 r4:00000000
[<c007a344>] (devm_request_threaded_irq) from [<c036ad4c>] (rsnd_src_probe_gen2+0x68/0x7c)
 r9:eef61120 r8:a0000113 r7:ee7ea8d8 r6:eef6113c r5:ee7ea8d0 r4:ee7e2138
[<c036ace4>] (rsnd_src_probe_gen2) from [<c0367e1c>] (rsnd_rdai_continuance_probe+0x80/0x29c)
 r5:eef61130 r4:c036ace4
[<c0367d9c>] (rsnd_rdai_continuance_probe) from [<c0368a80>] (rsnd_probe+0x114/0x304)
 r10:eef61110 r9:00000000 r8:ee7ea8d8 r7:eed90000 r6:eed90010 r5:ee7ea8d0
 r4:c048e960
[<c036896c>] (rsnd_probe) from [<c02667f4>] (platform_drv_probe+0x50/0xa0)
 r10:00000000 r9:c062f000 r8:c0624dec r7:00000000 r6:c0624dec r5:eed90010
 r4:fffffffe
[<c02667a4>] (platform_drv_probe) from [<c0264fac>] (driver_probe_device+0xfc/0x264)
 r6:00000000 r5:c0e1e9fc r4:eed90010 r3:c02667a4
[<c0264eb0>] (driver_probe_device) from [<c02651d8>] (__driver_attach+0x78/0x9c)
 r8:c0606460 r7:c0619e98 r6:c0624dec r5:eed90044 r4:eed90010 r3:00000000
[<c0265160>] (__driver_attach) from [<c02635c8>] (bus_for_each_dev+0x74/0x98)
 r6:c0265160 r5:c0624dec r4:00000000 r3:00000001
[<c0263554>] (bus_for_each_dev) from [<c0264a98>] (driver_attach+0x20/0x28)
 r6:ee7ea9c0 r5:00000000 r4:c0624dec
[<c0264a78>] (driver_attach) from [<c0264728>] (bus_add_driver+0xe8/0x1d0)
[<c0264640>] (bus_add_driver) from [<c0265868>] (driver_register+0xa4/0xe8)
 r7:c0606460 r6:00000000 r5:c05e6abc r4:c0624dec
[<c02657c4>] (driver_register) from [<c0266728>] (__platform_driver_register+0x50/0x64)
 r5:c05e6abc r4:ee7eec40
[<c02666d8>] (__platform_driver_register) from [<c05e6ad4>] (rsnd_driver_init+0x18/0x20)
[<c05e6abc>] (rsnd_driver_init) from [<c000a7d8>] (do_one_initcall+0x108/0x1bc)
[<c000a6d0>] (do_one_initcall) from [<c05c7dc8>] (kernel_init_freeable+0x11c/0x1e4)
 r9:c062f000 r8:c062f000 r7:c05fb160 r6:c05f3a40 r5:00000084 r4:00000006
[<c05c7cac>] (kernel_init_freeable) from [<c0445120>] (kernel_init+0x10/0xec)
 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:c0445110 r4:00000000
[<c0445110>] (kernel_init) from [<c000fef0>] (ret_from_fork+0x14/0x24)
 r4:00000000 r3:00000000

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds