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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
	Shubham Bansal <illusionist.neo@gmail.com>,
	Andrii Nakryiko <andrii@kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	bpf@vger.kernel.org, kernel-team@fb.com,
	Jiri Olsa <jolsa@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
	"David S . Miller" <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH bpf 1/4] ARM: unwind: Initialize the lr_addr field of unwind_ctrl_block
Date: Tue,  5 Apr 2022 18:33:47 +0900	[thread overview]
Message-ID: <164915122721.982637.1510683757540074397.stgit@devnote2> (raw)
In-Reply-To: <164915121498.982637.12787715964983738566.stgit@devnote2>

Since the unwind_ctrl_block::lr_addr is finally passed to
stackframe::lr_addr, that value will be exposed unconditionally.
Thus it should be initialized.

Without this fix, when unwind_frame() doesn't update the
unwind_ctrl_block::lr_addr (e.g. 'lr' register is not saved in the
target function), stackframe::lr_addr will contain a wrong value.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 arch/arm/kernel/unwind.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index a37ea6c772cd..93e767682cf4 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -404,6 +404,7 @@ int unwind_frame(struct stackframe *frame)
 	ctrl.vrs[SP] = frame->sp;
 	ctrl.vrs[LR] = frame->lr;
 	ctrl.vrs[PC] = 0;
+	ctrl.lr_addr = 0;
 
 	if (idx->insn == 1)
 		/* can't unwind */


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WARNING: multiple messages have this Message-ID (diff)
From: Masami Hiramatsu <mhiramat@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
	Shubham Bansal <illusionist.neo@gmail.com>,
	Andrii Nakryiko <andrii@kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	bpf@vger.kernel.org, kernel-team@fb.com,
	Jiri Olsa <jolsa@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
	"David S . Miller" <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
	Russell King <linux@armlinux.org.uk>,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH bpf 1/4] ARM: unwind: Initialize the lr_addr field of unwind_ctrl_block
Date: Tue,  5 Apr 2022 18:33:47 +0900	[thread overview]
Message-ID: <164915122721.982637.1510683757540074397.stgit@devnote2> (raw)
In-Reply-To: <164915121498.982637.12787715964983738566.stgit@devnote2>

Since the unwind_ctrl_block::lr_addr is finally passed to
stackframe::lr_addr, that value will be exposed unconditionally.
Thus it should be initialized.

Without this fix, when unwind_frame() doesn't update the
unwind_ctrl_block::lr_addr (e.g. 'lr' register is not saved in the
target function), stackframe::lr_addr will contain a wrong value.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 arch/arm/kernel/unwind.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index a37ea6c772cd..93e767682cf4 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -404,6 +404,7 @@ int unwind_frame(struct stackframe *frame)
 	ctrl.vrs[SP] = frame->sp;
 	ctrl.vrs[LR] = frame->lr;
 	ctrl.vrs[PC] = 0;
+	ctrl.lr_addr = 0;
 
 	if (idx->insn == 1)
 		/* can't unwind */


  reply	other threads:[~2022-04-05  9:35 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-05  9:33 [PATCH bpf 0/4] kprobes: rethook, ARM, arm64: Replace kretprobe trampoline with rethook Masami Hiramatsu
2022-04-05  9:33 ` [PATCH bpf 0/4] kprobes: rethook,ARM,arm64: " Masami Hiramatsu
2022-04-05  9:33 ` Masami Hiramatsu [this message]
2022-04-05  9:33   ` [PATCH bpf 1/4] ARM: unwind: Initialize the lr_addr field of unwind_ctrl_block Masami Hiramatsu
2022-04-06 18:53   ` kernel test robot
2022-04-06 18:53     ` kernel test robot
2022-04-05  9:33 ` [PATCH bpf 2/4] rethook, fprobe, kprobes: Check a failure in the rethook_hook() Masami Hiramatsu
2022-04-05  9:33   ` [PATCH bpf 2/4] rethook,fprobe,kprobes: " Masami Hiramatsu
2022-04-05  9:34 ` [PATCH bpf 3/4] ARM: rethook: Replace kretprobe trampoline with rethook Masami Hiramatsu
2022-04-05  9:34   ` Masami Hiramatsu
2022-04-05  9:34 ` [PATCH bpf 4/4] arm64: " Masami Hiramatsu
2022-04-05  9:34   ` Masami Hiramatsu
2022-04-05 17:40   ` kernel test robot
2022-04-05 17:40     ` kernel test robot
2022-04-05 21:25   ` kernel test robot
2022-04-05 21:25     ` kernel test robot

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