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authorLinus Torvalds <torvalds@linux-foundation.org>2011-05-07 13:17:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-07 13:17:37 -0700
commit8b061610dac3a3b89770c85ad63b481a47b0c38e (patch)
tree3ab93ad7f8f3e8bd612cff4e59d55d5a36c0c1fa /kernel
parentc2bf807eb347325988b1c7f9139e934ed9b1d795 (diff)
parent174a7b1f9692acad7f0ca2b02f696894201a6d94 (diff)
Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf tools: Makefile: Use gcc to determine ARCH perf events, x86: Fix Intel Nehalem and Westmere last level cache event definitions hw_breakpoints, powerpc: Fix CONFIG_HAVE_HW_BREAKPOINT off-case in ptrace_set_debugreg() sh, hw_breakpoints: Fix racy access to ptrace breakpoints arm, hw_breakpoints: Fix racy access to ptrace breakpoints powerpc, hw_breakpoints: Fix racy access to ptrace breakpoints x86, hw_breakpoints: Fix racy access to ptrace breakpoints ptrace: Prepare to fix racy accesses on task breakpoints
Diffstat (limited to 'kernel')
-rw-r--r--kernel/exit.c2
-rw-r--r--kernel/ptrace.c17
2 files changed, 18 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index f5d2f63bae0..8dd87418154 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1016,7 +1016,7 @@ NORET_TYPE void do_exit(long code)
/*
* FIXME: do that only when needed, using sched_exit tracepoint
*/
- flush_ptrace_hw_breakpoint(tsk);
+ ptrace_put_breakpoints(tsk);
exit_notify(tsk, group_dead);
#ifdef CONFIG_NUMA
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 0fc1eed28d2..dc7ab65f3b3 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -22,6 +22,7 @@
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/regset.h>
+#include <linux/hw_breakpoint.h>
/*
@@ -879,3 +880,19 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
return ret;
}
#endif /* CONFIG_COMPAT */
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+int ptrace_get_breakpoints(struct task_struct *tsk)
+{
+ if (atomic_inc_not_zero(&tsk->ptrace_bp_refcnt))
+ return 0;
+
+ return -1;
+}
+
+void ptrace_put_breakpoints(struct task_struct *tsk)
+{
+ if (atomic_dec_and_test(&tsk->ptrace_bp_refcnt))
+ flush_ptrace_hw_breakpoint(tsk);
+}
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */