From 927c7a9e92c4f69097a6e9e086d11fc2f8a5b40b Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 1 Jul 2010 16:20:36 +0200 Subject: perf: Fix race in callchains Now that software events don't have interrupt disabled anymore in the event path, callchains can nest on any context. So seperating nmi and others contexts in two buffers has become racy. Fix this by providing one buffer per nesting level. Given the size of the callchain entries (2040 bytes * 4), we now need to allocate them dynamically. v2: Fixed put_callchain_entry call after recursion. Fix the type of the recursion, it must be an array. v3: Use a manual pr cpu allocation (temporary solution until NMIs can safely access vmalloc'ed memory). Do a better separation between callchain reference tracking and allocation. Make the "put" path lockless for non-release cases. v4: Protect the callchain buffers with rcu. v5: Do the cpu buffers allocations node affine. Signed-off-by: Frederic Weisbecker Tested-by: Will Deacon Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Paul Mackerras Cc: Stephane Eranian Cc: Paul Mundt Cc: David Miller Cc: Borislav Petkov --- include/linux/perf_event.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 4db61dded388..d7e8ea690864 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -983,7 +983,6 @@ extern void perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs); extern void perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs); -extern struct perf_callchain_entry *perf_callchain_buffer(void); static inline void -- cgit v1.2.3