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6c8465a82a
When taking a CPU down for suspend and resume, a tracepoint may be called
when the CPU has been designated offline. As tracepoints require RCU for
protection, they must not be called if the current CPU is offline.
Unfortunately, trace_tlb_flush() is called in this scenario as was noted
by LOCKDEP:
...
Disabling non-boot CPUs ...
intel_pstate CPU 1 exiting
===============================
smpboot: CPU 1 didn't die...
[ INFO: suspicious RCU usage. ]
3.19.0-rc7-next-20150204.1-iniza-small #1 Not tainted
-------------------------------
include/trace/events/tlb.h:35 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
RCU used illegally from offline CPU!
rcu_scheduler_active = 1, debug_locks = 0
no locks held by swapper/1/0.
stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc7-next-20150204.1-iniza-small #1
Hardware name: SAMSUNG ELECTRONICS CO., LTD. 530U3BI/530U4BI/530U4BH/530U3BI/530U4BI/530U4BH, BIOS 13XK 03/28/2013
0000000000000001 ffff88011a44fe18 ffffffff817e370d 0000000000000011
ffff88011a448290 ffff88011a44fe48 ffffffff810d6847 ffff8800c66b9600
0000000000000001 ffff88011a44c000 ffffffff81cb3900 ffff88011a44fe78
Call Trace:
[<ffffffff817e370d>] dump_stack+0x4c/0x65
[<ffffffff810d6847>] lockdep_rcu_suspicious+0xe7/0x120
[<ffffffff810b71a5>] idle_task_exit+0x205/0x2c0
[<ffffffff81054c4e>] play_dead_common+0xe/0x50
[<ffffffff81054ca5>] native_play_dead+0x15/0x140
[<ffffffff8102963f>] arch_cpu_idle_dead+0xf/0x20
[<ffffffff810cd89e>] cpu_startup_entry+0x37e/0x580
[<ffffffff81053e20>] start_secondary+0x140/0x150
intel_pstate CPU 2 exiting
...
By converting the tlb_flush tracepoint to a TRACE_EVENT_CONDITION where the
condition is cpu_online(smp_processor_id()), we can avoid calling RCU protected
code when the CPU is offline.
Link: http://lkml.kernel.org/r/CA+icZUUGiGDoL5NU8RuxKzFjoLjEKRtUWx=JB8B9a0EQv-eGzQ@mail.gmail.com
Cc: stable@vger.kernel.org # 3.17+
Fixes: d17d8f9ded "x86/mm: Add tracepoints for TLB flushes"
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Hansen <dave@sr71.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
43 lines
974 B
C
43 lines
974 B
C
#undef TRACE_SYSTEM
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#define TRACE_SYSTEM tlb
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#if !defined(_TRACE_TLB_H) || defined(TRACE_HEADER_MULTI_READ)
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#define _TRACE_TLB_H
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#include <linux/mm_types.h>
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#include <linux/tracepoint.h>
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#define TLB_FLUSH_REASON \
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{ TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, \
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{ TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, \
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{ TLB_LOCAL_SHOOTDOWN, "local shootdown" }, \
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{ TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }
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TRACE_EVENT_CONDITION(tlb_flush,
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TP_PROTO(int reason, unsigned long pages),
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TP_ARGS(reason, pages),
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TP_CONDITION(cpu_online(smp_processor_id())),
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TP_STRUCT__entry(
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__field( int, reason)
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__field(unsigned long, pages)
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),
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TP_fast_assign(
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__entry->reason = reason;
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__entry->pages = pages;
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),
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TP_printk("pages:%ld reason:%s (%d)",
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__entry->pages,
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__print_symbolic(__entry->reason, TLB_FLUSH_REASON),
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__entry->reason)
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);
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#endif /* _TRACE_TLB_H */
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/* This part must be outside protection */
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#include <trace/define_trace.h>
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