From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DC71CCAC5B1 for ; Thu, 25 Sep 2025 02:09:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=adiBphAPScR6QQjh2KwjN5aarvz+PskpFpyHr3Y87gs=; b=oSFt8Gssz7HSwArLyrKccZJ+U9 SkfZHbN4zm47PI/8ONKffRDJpBJ8//jcwdn9+/bIz7F7moujH760LH+cjL/0DZN89sVQJCrsySQaS wW7I8cf6OLOCqd50lhbpjswN9qytAPKAAjivKd/bnXNpkmwFMastej12491KvYQ7bE+FU7WUzjoyI 4Bwi2apwjWS2E6MGGxb91ffg7OFMYiZw0DKc8ADqt2FvpRsuhae1dZKHRXbOMlOSC6dwSGzcmL1qv 8tV85ktJVqebx9teLTaFMYxKXPQFI9TrWnAyNj3mr1TEFrlUBSsmpMFDCqFXkLsDzsECjVr/Qk8m7 E7DIc2Sg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v1bPn-00000005GC7-3LhY; Thu, 25 Sep 2025 02:08:59 +0000 Received: from m16.mail.163.com ([220.197.31.3]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v1bPk-00000005GBG-0XZH for linux-arm-kernel@lists.infradead.org; Thu, 25 Sep 2025 02:08:57 +0000 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 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: PigvCgDnEQkXpNRowQcHEQ--.9650S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7tFyxur1kWF4xJrW8tr4xZwb_yoW8XFWkp3 9F9rykGFWDWFs0kw47WrsxXr15Cws3ArWrCry8Cw1akF4DZFyUCr9FkFWjkF1xA34Du3yx uF1avry5Cws8ZFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jjuWLUUUUU= X-Originating-IP: [116.128.244.169] X-CM-SenderInfo: p1dqww5hqjkmqzuzqiywtou0bp/1tbiVhrSeGjUYEjeAQABss X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250924_190856_583323_1C0D2528 X-CRM114-Status: GOOD ( 12.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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