c7cf0304d4
commit 4d230d12710646788af581ba0155d83ab48b955c upstream. Clocking operations clk_get/set_rate, are non-atomic, they shouldn't be called in soc_pcm_trigger() which is atomic. Following issue was found due to execution of clk_get_rate() causes sleep in soc_pcm_trigger(), which shouldn't be blocked. We can reproduce this issue by following > enable CONFIG_DEBUG_ATOMIC_SLEEP=y > compile, and boot > mount -t debugfs none /sys/kernel/debug > while true; do cat /sys/kernel/debug/clk/clk_summary > /dev/null; done & > while true; do aplay xxx; done This patch adds support to .prepare callback, and moves non-atomic clocking operations to it. As .prepare is non-atomic, it is always called before trigger_start/trigger_stop. BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620 in_atomic(): 1, irqs_disabled(): 128, pid: 2242, name: aplay INFO: lockdep is turned off. irq event stamp: 5964 hardirqs last enabled at (5963): [<ffff200008e59e40>] mutex_lock_nested+0x6e8/0x6f0 hardirqs last disabled at (5964): [<ffff200008e623f0>] _raw_spin_lock_irqsave+0x24/0x68 softirqs last enabled at (5502): [<ffff200008081838>] __do_softirq+0x560/0x10c0 softirqs last disabled at (5495): [<ffff2000080c2e78>] irq_exit+0x160/0x25c Preemption disabled at:[ 62.904063] [<ffff200008be4d48>] snd_pcm_stream_lock+0xb4/0xc0 CPU: 2 PID: 2242 Comm: aplay Tainted: G B C 4.9.54+ #186 Hardware name: Renesas Salvator-X board based on r8a7795 (DT) Call trace: [<ffff20000808fe48>] dump_backtrace+0x0/0x37c [<ffff2000080901d8>] show_stack+0x14/0x1c [<ffff2000086f4458>] dump_stack+0xfc/0x154 [<ffff2000081134a0>] ___might_sleep+0x57c/0x58c [<ffff2000081136b8>] __might_sleep+0x208/0x21c [<ffff200008e5980c>] mutex_lock_nested+0xb4/0x6f0 [<ffff2000087cac74>] clk_prepare_lock+0xb0/0x184 [<ffff2000087cb094>] clk_core_get_rate+0x14/0x54 [<ffff2000087cb0f4>] clk_get_rate+0x20/0x34 [<ffff20000113aa00>] rsnd_adg_ssi_clk_try_start+0x158/0x4f8 [snd_soc_rcar] [<ffff20000113da00>] rsnd_ssi_init+0x668/0x7a0 [snd_soc_rcar] [<ffff200001133ff4>] rsnd_soc_dai_trigger+0x4bc/0xcf8 [snd_soc_rcar] [<ffff200008c1af24>] soc_pcm_trigger+0x2a4/0x2d4 Fixes: e7d850dd10f4 ("ASoC: rsnd: use mod base common method on SSI-parent") Signed-off-by: Jiada Wang <jiada_wang@mentor.com> Signed-off-by: Timo Wischer <twischer@de.adit-jv.com> [Kuninori: tidyup for upstream] Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Tested-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.