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authorThomas Gleixner <tglx@linutronix.de>2017-10-03 17:39:02 +0300
committerThomas Gleixner <tglx@linutronix.de>2017-10-04 11:53:54 +0300
commit34ddaa3e5c0096fef52485186c7eb6cf56ddc686 (patch)
tree3d98dfe007218f46a0b9b287fb2fe58b4797a9d5 /include/linux/nmi.h
parente31d6883f21c1cdfe5bc64e28411f8a92b783fde (diff)
downloadlinux-34ddaa3e5c0096fef52485186c7eb6cf56ddc686.tar.xz
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/linux/nmi.h')
-rw-r--r--include/linux/nmi.h1
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.