Re: [PATCH] x86, perf: check that current->mm alive before gettinguser callchain

[Peter Zijlstra]

On Tue, 2011-08-30 at 12:32 +0400, Andrey Vagin wrote:
> An event may occurs when mm is already released.

> Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx>
> ---
>  arch/x86/kernel/cpu/perf_event.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
> index 4ee3abf..cfa62ec 100644
> --- a/arch/x86/kernel/cpu/perf_event.c
> +++ b/arch/x86/kernel/cpu/perf_event.c
> @@ -1900,6 +1900,9 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
>  
>  	perf_callchain_store(entry, regs->ip);
>  
> +	if (!current->mm)
> +		return;
> +
>  	if (perf_callchain_user32(regs, entry))
>  		return;
>  

Thanks!
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