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authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>2017-10-17 13:48:34 +0530
committerIngo Molnar <mingo@kernel.org>2017-10-18 15:21:35 +0200
commit4f3a871443669c6b4d458a60ac8d8ca5eedc3f97 (patch)
tree44ee4a6308eca2341ed70dc9accc001bb75300f8 /kernel/kprobes.c
parent4b50239a769e78bbe362fc92c3f8bd5415a4a5f5 (diff)
downloadlwn-4f3a871443669c6b4d458a60ac8d8ca5eedc3f97.tar.gz
lwn-4f3a871443669c6b4d458a60ac8d8ca5eedc3f97.zip
Revert "kprobes: Warn if optprobe handler tries to change execution path"
This reverts commit: e863d539614641 ("kprobes: Warn if optprobe handler tries to change execution path") On PowerPC, we place a probe at kretprobe_trampoline to catch function returns and with CONFIG_OPTPROBES=y, this probe gets optimized. This works for us due to the way we handle the optprobe as described in commit: 762df10bad6954 ("powerpc/kprobes: Optimize kprobe in kretprobe_trampoline()") With the above commit, we end up with a warning. As such, revert this change. Reported-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20171017081834.3629-1-naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2d28377a0e32..15fba7fe57c8 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -387,10 +387,7 @@ void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
list_for_each_entry_rcu(kp, &p->list, list) {
if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
set_kprobe_instance(kp);
- if (kp->pre_handler(kp, regs)) {
- if (WARN_ON_ONCE(1))
- pr_err("Optprobe ignores instruction pointer changing.(%pF)\n", p->addr);
- }
+ kp->pre_handler(kp, regs);
}
reset_kprobe_instance();
}