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authorDavid S. Miller <davem@davemloft.net>2010-04-11 02:44:30 -0700
committerDavid S. Miller <davem@davemloft.net>2010-04-11 02:44:30 -0700
commit4a1032faac94ebbf647460ae3e06fc21146eb280 (patch)
tree7f31b97beb0406faa1523e619289ad0ab07c9787 /kernel/trace/trace_event_perf.c
parentae4e8d63b5619d4d95f1d2bfa2b836caa6e62d06 (diff)
parent0eddb519b9127c73d53db4bf3ec1d45b13f844d1 (diff)
Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
Diffstat (limited to 'kernel/trace/trace_event_perf.c')
-rw-r--r--kernel/trace/trace_event_perf.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 81f691eb3a3..0565bb42566 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -17,7 +17,12 @@ EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs);
static char *perf_trace_buf;
static char *perf_trace_buf_nmi;
-typedef typeof(char [PERF_MAX_TRACE_SIZE]) perf_trace_t ;
+/*
+ * Force it to be aligned to unsigned long to avoid misaligned accesses
+ * suprises
+ */
+typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)])
+ perf_trace_t;
/* Count the events in use (per event id, not per instance) */
static int total_ref_count;
@@ -130,6 +135,8 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
char *trace_buf, *raw_data;
int pc, cpu;
+ BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
+
pc = preempt_count();
/* Protect the per cpu buffer, begin the rcu read side */
@@ -152,7 +159,7 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
raw_data = per_cpu_ptr(trace_buf, cpu);
/* zero the dead bytes from align to not leak stack to user */
- *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+ memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
entry = (struct trace_entry *)raw_data;
tracing_generic_entry_update(entry, *irq_flags, pc);