From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B2DB725487A; Thu, 25 Sep 2025 02:09:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.3 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758766150; cv=none; b=WEgBCKDsh1+N1rJV/JHpMLHlubYNypwSZldhtQis0M4O1t2UUszccT32e/RhKDtz/vtMUzek6Y8zT9oIn6mA1dy0vp9hkgFCo4YZeDOdSQIzluNcEdr6RjxVgQmOeJFkJVTE0PIbHYXeNcvpCy+SFkBx76MVClgmNIwmATAJMkc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758766150; c=relaxed/simple; bh=dvEeJZpALUXHQn8Map8RbBvlT9jD/7M8DMbRjpo3D4w=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=nE26DM0Uqumfpr7C61Kg5il8ItwPnfS9L/YGHWzvgAQLDHoBjauk7yMgnO9qV/Ia7x2JKJdegv2Irv2L75dz4ulIQ6iWrAF87rgShy2/utEDk8kNIQq6aax02gEoJaXBR0gBuFfEWQ6moH9B/QzPF6vfO+3YMIX70ZRIVkhVl5o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=WjzIx70L; arc=none smtp.client-ip=117.135.210.3 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="WjzIx70L" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=ad iBphAPScR6QQjh2KwjN5aarvz+PskpFpyHr3Y87gs=; b=WjzIx70LpoyMNUwCIh ePB4aB07F7rsQrRR/e9WPkjqZgFTnVXn+ilrjtG3btzPXzxyt4Bw3Bch3tRw3RgX G8/lxsmodMkMGGdq8UqCKLDF6EtEsIXwhwzs2JtslgNJ4+d7EEX5x48n62Gq/osK wYuql/ibaoeh7FrMobRX80/gI= Received: from localhost.localdomain (unknown []) by gzsmtp3 (Coremail) with SMTP id PigvCgDnEQkXpNRowQcHEQ--.9650S2; Thu, 25 Sep 2025 10:08:24 +0800 (CST) From: Feng Yang To: rostedt@goodmis.org, mhiramat@kernel.org, mark.rutland@arm.com, catalin.marinas@arm.com, will@kernel.org, revest@chromium.org, alexei.starovoitov@gmail.com, olsajiri@gmail.com, andrii@kernel.org, ast@kernel.org Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, bpf@vger.kernel.org Subject: [PATCH] tracing: Fix the bug where bpf_get_stackid returns -EFAULT on the ARM64 Date: Thu, 25 Sep 2025 10:08:22 +0800 Message-Id: <20250925020822.119302-1-yangfeng59949@163.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:PigvCgDnEQkXpNRowQcHEQ--.9650S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7tFyxur1kWF4xJrW8tr4xZwb_yoW8XFWkp3 9F9rykGFWDWFs0kw47WrsxXr15Cws3ArWrCry8Cw1akF4DZFyUCr9FkFWjkF1xA34Du3yx uF1avry5Cws8ZFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jjuWLUUUUU= X-CM-SenderInfo: p1dqww5hqjkmqzuzqiywtou0bp/1tbiVhrSeGjUYEjeAQABss From: Feng Yang When using bpf_program__attach_kprobe_multi_opts on ARM64 to hook a BPF program that contains the bpf_get_stackid function, the BPF program fails to obtain the stack trace and returns -EFAULT. This is because ftrace_partial_regs omits the configuration of the pstate register, leaving pstate at the default value of 0. When get_perf_callchain executes, it uses user_mode(regs) to determine whether it is in kernel mode. This leads to a misjudgment that the code is in user mode, so perf_callchain_kernel is not executed and the function returns directly. As a result, trace->nr becomes 0, and finally -EFAULT is returned. Therefore, the assignment of the pstate register is added here. Fixes: b9b55c8912ce ("tracing: Add ftrace_partial_regs() for converting ftrace_regs to pt_regs") Closes: https://lore.kernel.org/bpf/20250919071902.554223-1-yangfeng59949@163.com/ Signed-off-by: Feng Yang --- arch/arm64/include/asm/ftrace.h | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index bfe3ce9df197..ba7cf7fec5e9 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -153,6 +153,7 @@ ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs) regs->pc = afregs->pc; regs->regs[29] = afregs->fp; regs->regs[30] = afregs->lr; + regs->pstate = PSR_MODE_EL1h; return regs; } -- 2.25.1