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From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Masami Hiramatsu <mhiramat@kernel.org>
Cc: bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org, Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 2/3] bpf/trampoline: Allow ftrace location to differ from trampoline attach address
Date: Thu, 17 Feb 2022 17:06:24 +0530	[thread overview]
Message-ID: <2a32e4723f7e56c675ffd6aa0762789e56dce2e1.1645096227.git.naveen.n.rao@linux.vnet.ibm.com> (raw)
In-Reply-To: <cover.1645096227.git.naveen.n.rao@linux.vnet.ibm.com>

On some architectures, ftrace location can include multiple
instructions, and does not necessarily match the function entry address
returned by kallsyms_lookup(). Drop the check in is_ftrace_location() to
accommodate the same.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
 kernel/bpf/trampoline.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 4b6974a195c138..c47c80874bee3f 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -124,8 +124,6 @@ static int is_ftrace_location(void *ip)
 	addr = ftrace_location((long)ip);
 	if (!addr)
 		return 0;
-	if (WARN_ON_ONCE(addr != (long)ip))
-		return -EFAULT;
 	return 1;
 }
 
-- 
2.35.1


  parent reply	other threads:[~2022-02-17 11:38 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-17 11:36 [PATCH 0/3] powerpc/ftrace: Reserve instructions from function entry for ftrace Naveen N. Rao
2022-02-17 11:36 ` [PATCH 1/3] " Naveen N. Rao
2022-02-17 19:46   ` kernel test robot
2022-02-21  0:10   ` Masami Hiramatsu
2022-02-17 11:36 ` Naveen N. Rao [this message]
2022-02-17 11:36 ` [PATCH 3/3] kprobes: Allow probing on any address belonging to ftrace Naveen N. Rao
2022-02-18  6:45   ` Naveen N. Rao
2022-02-21  0:15   ` Masami Hiramatsu

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