From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3170E25EF93; Tue, 11 Mar 2025 15:05:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741705504; cv=none; b=LaBYbcJJQK5KOoCWaWcxfKjUwXXDTfupmfW7hPiG1FzIR4foD6RQC9cZigRtdVdG/0xuDmex4odvEhSGVBWP7Ljq5RrzAdbCOi5yBtME39/VeozHrHhgx4DFnw7B8eXGU1ytvLUKxYCe/nFm2CAHYbofXUcNf2ckSYebm934KXA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741705504; c=relaxed/simple; bh=x9Gk9+3pp4oSEwTWujYIqzTbGzminu4gy8QuncAVDpg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tv1bJaUixUi6dvV1EP8xrA+bM2/wercnIGt9VC4NHqKAk/jXML19eNHo/DPtBAkWl+remGM8lClbWSUOpsP1NGZ1VdHCEC9YTnphR5UfdE5uAmMzpdu7tintuuDZV7/tUjFSZi9i3akV0a66ak7D8K73vt+wuZHwda18rydf8UI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wvCyb9N2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="wvCyb9N2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A379CC4CEF0; Tue, 11 Mar 2025 15:05:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741705504; bh=x9Gk9+3pp4oSEwTWujYIqzTbGzminu4gy8QuncAVDpg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wvCyb9N2JcOLnawyGpZUFxTbF0xl4aKkZaOafMHkJDxt5yzSKVTFhEUlxyCR42+Va iidpMSpUmk6FK0A/Pe8p0UUoMlQBFTa/DJsV8I48FOcB/fnLpYjKYaXc4ujp4fWw8y 1iyTMAx25md5ydvFNVTYSpkb8V7Rl1VVge0jySLk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+97da3d7e0112d59971de@syzkaller.appspotmail.com, Puranjay Mohan , Yonghong Song , Alexei Starovoitov , Sasha Levin Subject: [PATCH 5.4 041/328] bpf: Send signals asynchronously if !preemptible Date: Tue, 11 Mar 2025 15:56:51 +0100 Message-ID: <20250311145716.525757606@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250311145714.865727435@linuxfoundation.org> References: <20250311145714.865727435@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Puranjay Mohan [ Upstream commit 87c544108b612512b254c8f79aa5c0a8546e2cc4 ] BPF programs can execute in all kinds of contexts and when a program running in a non-preemptible context uses the bpf_send_signal() kfunc, it will cause issues because this kfunc can sleep. Change `irqs_disabled()` to `!preemptible()`. Reported-by: syzbot+97da3d7e0112d59971de@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67486b09.050a0220.253251.0084.GAE@google.com/ Fixes: 1bc7896e9ef4 ("bpf: Fix deadlock with rq_lock in bpf_send_signal()") Signed-off-by: Puranjay Mohan Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20250115103647.38487-1-puranjay@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- kernel/trace/bpf_trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 4a31763a8c5d7..ac3125d0c73f1 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -653,7 +653,7 @@ BPF_CALL_1(bpf_send_signal, u32, sig) if (unlikely(is_global_init(current))) return -EPERM; - if (irqs_disabled()) { + if (!preemptible()) { /* Do an early check on signal validity. Otherwise, * the error is lost in deferred irq_work. */ -- 2.39.5