3a40cfe8ba
We will meet below issue due to mutex_lock() is called in interrupt context. The mutex lock is used to protect the pattern trigger data, but before changing new pattern trigger data (pattern values or repeat value) by users, we always cancel the timer firstly to clear previous patterns' performance. That means there is no race in pattern_trig_timer_function(), so we can drop the mutex lock in pattern_trig_timer_function() to avoid this issue. Moreover we can move the timer cancelling into mutex protection, since there is no deadlock risk if we remove the mutex lock in pattern_trig_timer_function(). BUG: sleeping function called from invalid context at kernel/locking/mutex.c:254 in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper/1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.20.0-rc1-koelsch-00841-ga338c8181013c1a9 #171 Hardware name: Generic R-Car Gen2 (Flattened Device Tree) [<c020f19c>] (unwind_backtrace) from [<c020aecc>] (show_stack+0x10/0x14) [<c020aecc>] (show_stack) from [<c07affb8>] (dump_stack+0x7c/0x9c) [<c07affb8>] (dump_stack) from [<c02417d4>] (___might_sleep+0xf4/0x158) [<c02417d4>] (___might_sleep) from [<c07c92c4>] (mutex_lock+0x18/0x60) [<c07c92c4>] (mutex_lock) from [<c067b28c>] (pattern_trig_timer_function+0x1c/0x11c) [<c067b28c>] (pattern_trig_timer_function) from [<c027f6fc>] (call_timer_fn+0x1c/0x90) [<c027f6fc>] (call_timer_fn) from [<c027f944>] (expire_timers+0x94/0xa4) [<c027f944>] (expire_timers) from [<c027fc98>] (run_timer_softirq+0x108/0x15c) [<c027fc98>] (run_timer_softirq) from [<c02021cc>] (__do_softirq+0x1d4/0x258) [<c02021cc>] (__do_softirq) from [<c0224d24>] (irq_exit+0x64/0xc4) [<c0224d24>] (irq_exit) from [<c0268dd0>] (__handle_domain_irq+0x80/0xb4) [<c0268dd0>] (__handle_domain_irq) from [<c045e1b0>] (gic_handle_irq+0x58/0x90) [<c045e1b0>] (gic_handle_irq) from [<c02019f8>] (__irq_svc+0x58/0x74) Exception stack(0xeb483f60 to 0xeb483fa8) 3f60: 00000000 00000000 eb9afaa0 c0217e80 00000000 ffffe000 00000000 c0e06408 3f80: 00000002 c0e0647c c0c6a5f0 00000000 c0e04900 eb483fb0 c0207ea8 c0207e98 3fa0: 60020013 ffffffff [<c02019f8>] (__irq_svc) from [<c0207e98>] (arch_cpu_idle+0x1c/0x38) [<c0207e98>] (arch_cpu_idle) from [<c0247ca8>] (do_idle+0x138/0x268) [<c0247ca8>] (do_idle) from [<c0248050>] (cpu_startup_entry+0x18/0x1c) [<c0248050>] (cpu_startup_entry) from [<402022ec>] (0x402022ec) Fixes: 5fd752b6b3a2 ("leds: core: Introduce LED pattern trigger") Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Reported-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
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.