tracepoint: Fix race between tracing and removing tracepoint
commit c8b186a8 upstream. When executing a tracepoint, the tracepoint's func is dereferenced twice - in __DO_TRACE() (where the returned pointer is checked) and later on in __traceiter_##_name where the returned pointer is dereferenced without checking which leads to races against tracepoint_removal_sync() and crashes. This adds a check before referencing the pointer in tracepoint_ptr_deref. Link: https://lkml.kernel.org/r/20210202072326.120557-1-aik@ozlabs.ru Cc: stable@vger.kernel.org Fixes: d25e37d8 ("tracepoint: Optimize using static_call()") Acked-by:Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:
Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parent
9e4a668f
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