diff options
| author | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2016-01-15 11:34:21 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-03-03 15:07:15 -0800 |
| commit | c0cbcf2cb59c076f4ff6422153534dd2762c3d44 (patch) | |
| tree | f09556b39fb0ed309ab895b523c6060ba0d54f8e /drivers/clocksource | |
| parent | b8175b171fde996b5306fd113bd865506166df19 (diff) | |
clockevents/tcb_clksrc: Prevent disabling an already disabled clock
commit f02b4b72d12cbae7020a959e2ed0410a464b4cc4 upstream.
clockevents_exchange_device is calling clockevents_shutdown() on the new
clockenvents device but it may have never been enabled in the first place.
This results in the tcb clock being disabled without being enabled first:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:680 clk_disable+0x28/0x34()
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 4.4.0+ #6
Hardware name: Atmel AT91SAM9
[<c000f2b8>] (unwind_backtrace) from [<c000d01c>] (show_stack+0x10/0x14)
[<c000d01c>] (show_stack) from [<c00172f0>] (warn_slowpath_common+0x78/0xa0)
[<c00172f0>] (warn_slowpath_common) from [<c00173a8>] (warn_slowpath_null+0x18/0x20)
[<c00173a8>] (warn_slowpath_null) from [<c0361528>] (clk_disable+0x28/0x34)
[<c0361528>] (clk_disable) from [<c034d560>] (tc_shutdown+0x38/0x4c)
[<c034d560>] (tc_shutdown) from [<c0059ad4>] (clockevents_switch_state+0x38/0x6c)
[<c0059ad4>] (clockevents_switch_state) from [<c0059b18>] (clockevents_shutdown+0x10/0x24)
[<c0059b18>] (clockevents_shutdown) from [<c005a458>] (tick_check_new_device+0x84/0xac)
[<c005a458>] (tick_check_new_device) from [<c0059660>] (clockevents_register_device+0x7c/0x108)
[<c0059660>] (clockevents_register_device) from [<c06b5a68>] (tcb_clksrc_init+0x390/0x3e8)
[<c06b5a68>] (tcb_clksrc_init) from [<c00097cc>] (do_one_initcall+0x114/0x1d4)
[<c00097cc>] (do_one_initcall) from [<c069bd54>] (kernel_init_freeable+0xfc/0x1b8)
[<c069bd54>] (kernel_init_freeable) from [<c04c3818>] (kernel_init+0x8/0xe0)
[<c04c3818>] (kernel_init) from [<c000a410>] (ret_from_fork+0x14/0x24)
---[ end trace 0000000000000001 ]---
Check what state we were in before trying to disable the clock.
Fixes: cf4541c101ea ("clockevents/drivers/tcb_clksrc: Migrate to new 'set-state' interface")
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: http://lkml.kernel.org/r/1452854061-30370-1-git-send-email-alexandre.belloni@free-electrons.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/tcb_clksrc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c index 6ee91401918e..4da2af9694a2 100644 --- a/drivers/clocksource/tcb_clksrc.c +++ b/drivers/clocksource/tcb_clksrc.c @@ -98,7 +98,8 @@ static int tc_shutdown(struct clock_event_device *d) __raw_writel(0xff, regs + ATMEL_TC_REG(2, IDR)); __raw_writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR)); - clk_disable(tcd->clk); + if (!clockevent_state_detached(d)) + clk_disable(tcd->clk); return 0; } |