Messages in this thread Patch in this message | | | Date | Tue, 18 Mar 2014 17:01:59 +0200 | From | Grygorii Strashko <> | Subject | [linux-next][regression] [PATCH] percpu: add preemption checks to __this_cpu ops |
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Hi All,
The regression is observed in the current linux-next on ARM Keystone 2 SoC: - system is booted till console and in a second or two and then stall, no messages displayed (CONFIG_DEBUG_PREEMPT=y).
The cause of regression has been bisected to the commit:
commit 589a606f9539663f162e4a110d117527833b58a4 Author: Christoph Lameter <cl@linux.com> Date: Mon Mar 17 11:27:41 2014 +1100
percpu: add preemption checks to __this_cpu ops
We define a check function in order to avoid trouble with the include files. Then the higher level __this_cpu macros are modified to invoke the preemption check.
Signed-off-by: Christoph Lameter <cl@linux.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[=== 1 ===] If above patch is reverted - system can boot again.
[=== 2 ===] If I apply below change - system can boot again.
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c index a270dce..73a2004 100644 --- a/lib/smp_processor_id.c +++ b/lib/smp_processor_id.c @@ -58,9 +58,6 @@ EXPORT_SYMBOL(debug_smp_processor_id); notrace void __this_cpu_preempt_check(const char *op) { - char text[40]; - - snprintf(text, sizeof(text), "__this_cpu_%s()", op); - check_preemption_disabled(text); + check_preemption_disabled(op); } EXPORT_SYMBOL(__this_cpu_preempt_check);
linux-next top commits: 3bd688c Add linux-next specific files for 20140318 9a63a74 Merge branch 'akpm/master' ccdf335 mm: add strictlimit knob 589a606 percpu: add preemption checks to __this_cpu ops cdbd87c net: replace __this_cpu_inc in route.c with raw_cpu_inc 049fcfe modules: use raw_cpu_write for initialization of per cpu refcount. b46b094 mm: use raw_cpu ops for determining current NUMA node d934df8 percpu: add raw_cpu_ops c4a8790 arm: move arm_dma_limit to setup_dma_zone
Regards, -grygorii
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