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| author |   Thomas Gleixner <tglx@linutronix.de> | 2017-10-03 16:39:02 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-10-04 10:53:54 +0200 |
| commit | 34ddaa3e5c0096fef52485186c7eb6cf56ddc686 (patch) | |
| tree | 3d98dfe007218f46a0b9b287fb2fe58b4797a9d5 /include | |
| parent | watchdog/core, powerpc: Lock cpus across reconfiguration (diff) | |
| download | linux-dev-34ddaa3e5c0096fef52485186c7eb6cf56ddc686.tar.xz linux-dev-34ddaa3e5c0096fef52485186c7eb6cf56ddc686.zip | |
powerpc/watchdog: Make use of watchdog_nmi_probe()
The rework of the core hotplug code triggers the WARN_ON in start_wd_cpu()
on powerpc because it is called multiple times for the boot CPU.
The first call is via:
start_wd_on_cpu+0x80/0x2f0
watchdog_nmi_reconfigure+0x124/0x170
softlockup_reconfigure_threads+0x110/0x130
lockup_detector_init+0xbc/0xe0
kernel_init_freeable+0x18c/0x37c
kernel_init+0x2c/0x160
ret_from_kernel_thread+0x5c/0xbc
And then again via the CPU hotplug registration:
start_wd_on_cpu+0x80/0x2f0
cpuhp_invoke_callback+0x194/0x620
cpuhp_thread_fun+0x7c/0x1b0
smpboot_thread_fn+0x290/0x2a0
kthread+0x168/0x1b0
ret_from_kernel_thread+0x5c/0xbc
This can be avoided by setting up the cpu hotplug state with nocalls and
move the initialization to the watchdog_nmi_probe() function. That
initializes the hotplug callbacks without invoking the callback and the
following core initialization function then configures the watchdog for the
online CPUs (in this case CPU0) via softlockup_reconfigure_threads().
Reported-and-tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/nmi.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/nmi.h b/include/linux/nmi.h index 0c9ed49fb21a..27e249ed7c5c 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -111,6 +111,7 @@ static inline int hardlockup_detector_perf_init(void) { return 0; } void watchdog_nmi_stop(void); void watchdog_nmi_start(void); +int watchdog_nmi_probe(void); /** * touch_nmi_watchdog - restart NMI watchdog timeout. |