* Re: perf record -g hangs the system
2010-01-21 11:10 perf record -g hangs the system Luca Barbieri
@ 2010-01-21 11:18 ` Frederic Weisbecker
2010-01-21 12:19 ` Luca Barbieri
0 siblings, 1 reply; 3+ messages in thread
From: Frederic Weisbecker @ 2010-01-21 11:18 UTC (permalink / raw)
To: Luca Barbieri; +Cc: linux-kernel
On Thu, Jan 21, 2010 at 12:10:12PM +0100, Luca Barbieri wrote:
> I'm experiencing a system lockup running the following command:
> perf record -g true
>
> The system hangs and does not respond to any sysrq.
> No messages are printed to netconsole.
>
> This is with 2.6.33-rc4 on an x86-32 Core 2 dual core machine.
>
> Any tips on how to debug/fix this?
It should be fixed in latest linus's git tree with the
following patch:
commit c2c5d45d46c8c0fd34291dec958670ad4816796f
Author: Frederic Weisbecker <fweisbec@gmail.com>
Date: Thu Dec 31 03:52:25 2009 +0100
perf: Stop stack frame walking off kernel addresses boundaries
While processing kernel perf callchains, an bad entry can be
considered as a valid stack pointer but not as a kernel address.
In this case, we hang in an endless loop. This can happen in an
x86-32 kernel after processing the last entry in a kernel
stacktrace.
Just stop the stack frame walking after we encounter an invalid
kernel address.
This fixes a hard lockup in x86-32.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1262227945-27014-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index c56bc28..6d81755 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -123,13 +123,15 @@ print_context_stack_bp(struct thread_info *tinfo,
while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
unsigned long addr = *ret_addr;
- if (__kernel_text_address(addr)) {
- ops->address(data, addr, 1);
- frame = frame->next_frame;
- ret_addr = &frame->return_address;
- print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
- }
+ if (!__kernel_text_address(addr))
+ break;
+
+ ops->address(data, addr, 1);
+ frame = frame->next_frame;
+ ret_addr = &frame->return_address;
+ print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
}
+
return (unsigned long)frame;
}
EXPORT_SYMBOL_GPL(print_context_stack_bp);
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