tracing/syscalls: Fix perf syscall tracing when syscall_nr == -1
syscall_get_nr can return -1 in the case that the task is not executing
a system call.
This patch fixes perf_syscall_{enter,exit} to check that the syscall
number is valid before using it as an index into a bitmap.
Link: http://lkml.kernel.org/r/1345137254-7377-1-git-send-email-will.deacon@arm.com
Change-Id: I12f99dea41390b9631f98f925dc1d572aa4fc22d
Cc: Jason Baron <jbaron@redhat.com>
Cc: Wade Farnsworth <wade_farnsworth@mentor.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index c9ce09a..aed38fd 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -519,6 +519,8 @@
int size;
syscall_nr = syscall_get_nr(current, regs);
+ if (syscall_nr < 0)
+ return;
if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
return;
@@ -593,6 +595,8 @@
int size;
syscall_nr = syscall_get_nr(current, regs);
+ if (syscall_nr < 0)
+ return;
if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
return;