LKML Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH -tip] kprobes/x86: Use preempt_enable() in optimized_callback()
@ 2018-10-20  9:47 Masami Hiramatsu
  2018-10-21 20:42 ` Peter Zijlstra
  2018-10-22  1:33 ` [tip:perf/core] " tip-bot for Masami Hiramatsu
  0 siblings, 2 replies; 3+ messages in thread
From: Masami Hiramatsu @ 2018-10-20  9:47 UTC (permalink / raw)
  To: Ingo Molnar
  Cc: Andy Lutomirski, Alexei Starovoitov, Oleg Nesterov,
	Peter Zijlstra, H . Peter Anvin, Thomas Gleixner, X86 ML,
	Borislav Petkov, dwmw, Masami Hiramatsu, linux-kernel

Since commit a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from
ftrace-based/optimized kprobes”) removes local_irq_save/restore()
from optimized_callback(), the handler does not protected against
reschedule interrupt. If it is able to be preempted (rescheduled)
by such interrupt, we don't need to use _no_resched macro.
Let's use preempt_enable() instead.

Fixes: a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes”)
Link: https://lkml.kernel.org/r/37CB98C2-AF9B-475B-8B2D-7B414DC491F3@vmware.com
Reported-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 arch/x86/kernel/kprobes/opt.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index eaf02f2e7300..40b16b270656 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -179,7 +179,7 @@ optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
 		opt_pre_handler(&op->kp, regs);
 		__this_cpu_write(current_kprobe, NULL);
 	}
-	preempt_enable_no_resched();
+	preempt_enable();
 }
 NOKPROBE_SYMBOL(optimized_callback);
 


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, back to index

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-10-20  9:47 [PATCH -tip] kprobes/x86: Use preempt_enable() in optimized_callback() Masami Hiramatsu
2018-10-21 20:42 ` Peter Zijlstra
2018-10-22  1:33 ` [tip:perf/core] " tip-bot for Masami Hiramatsu

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git