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From: Oleg Nesterov <oleg@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
	syzbot <syzbot+30d675e3ca03c1c351e7@syzkaller.appspotmail.com>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH] uprobes/x86: remove the wrong WARN_ON() in uprobe_init_insn()
Date: Fri, 18 May 2018 18:27:39 +0200	[thread overview]
Message-ID: <20180518162739.GA5559@redhat.com> (raw)
In-Reply-To: <000000000000b759cf056c2b3c12@google.com>

insn_get_length() has the side-effect of processing the entire instruction
but only if it was decoded successfully, otherwise insn_complete() can fail
and in this case we need to just return an error without warning.

Reported-by: syzbot+30d675e3ca03c1c351e7@syzkaller.appspotmail.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 arch/x86/kernel/uprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 85c7ef2..efd7ee9 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -293,7 +293,7 @@ static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool
 	insn_init(insn, auprobe->insn, sizeof(auprobe->insn), x86_64);
 	/* has the side-effect of processing the entire instruction */
 	insn_get_length(insn);
-	if (WARN_ON_ONCE(!insn_complete(insn)))
+	if (!insn_complete(insn))
 		return -ENOEXEC;
 
 	if (is_prefix_bad(insn))
-- 
2.5.0

  parent reply	other threads:[~2018-05-18 16:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-14 14:24 WARNING in arch_uprobe_analyze_insn syzbot
2018-05-15 13:36 ` Oleg Nesterov
2018-05-15 14:48   ` Masami Hiramatsu
2018-05-15 16:18     ` Oleg Nesterov
2018-05-18 16:27 ` Oleg Nesterov [this message]
2018-05-18 23:58   ` [PATCH] uprobes/x86: remove the wrong WARN_ON() in uprobe_init_insn() Masami Hiramatsu

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