Messages in this thread Patch in this message | | | From | "Naveen N. Rao" <> | Subject | [PATCH] Revert "kprobes: Warn if optprobe handler tries to change execution path" | Date | Tue, 17 Oct 2017 13:48:34 +0530 |
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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, 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> --- Discussion here: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1510995.html
kernel/kprobes.c | 5 +---- 1 file changed, 1 insertion(+), 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(); } -- 2.14.2
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