From nobody Tue Apr 7 12:42:29 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 212DBC4332F for ; Mon, 17 Oct 2022 10:05:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231487AbiJQKFJ (ORCPT ); Mon, 17 Oct 2022 06:05:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230201AbiJQKE6 (ORCPT ); Mon, 17 Oct 2022 06:04:58 -0400 Received: from mail-pf1-x434.google.com (mail-pf1-x434.google.com [IPv6:2607:f8b0:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08CE61EEE8 for ; Mon, 17 Oct 2022 03:04:50 -0700 (PDT) Received: by mail-pf1-x434.google.com with SMTP id p14so10636578pfq.5 for ; Mon, 17 Oct 2022 03:04:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=RuPi2kJWnTKaT4aVfokzpN9MYv+IdW9MQr50PHecKpc=; b=YqrS+attN7r6MY97eZcauP2HvFXu4WYJG9YWeF68qJKfCeX4QvaDqnSIf7HRVaCGBu dyfX63Th9wv9ekjiN4sNRwIFAJOIH8V4CW4DoGjI3E7NrGgyqpxqX+Gb5LVgxMrT5iph kp6diM4a3u4zvnIh9+qT9M+bISfNBPi8ilhCdN3gfZRoX92oalbeY8NOo61j4icEA/LU TUl+caQH8o+IfOQx/Gr6iJFRzWFJPl+UVKH7dEsC69z1Fe5CI6CfnwEUnXtLFS62gjmj I6WvoOaJkOq2dj2Tj2qjCVWcvVNYoBZLQd7VkGTI0YotieAGsHB8qRroUGsYyI6JNS3Q 9Lrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=RuPi2kJWnTKaT4aVfokzpN9MYv+IdW9MQr50PHecKpc=; b=65VFBUC3qg+GRhN9diKHEPQbKR0k+a4ZM8I7eCnfjpjRwU1ycrejG4pYqxC2VgF94v ctuTrmprKOh9pX2Ch0zU4CKf2PCM5+OoD0pQ12ud8udMuGl6yFw7f4L4pu1wjWUHiYuX p9bJO6NCmkC8pmPqxNb2aeAF6XJwnWaeTlSzrhhyGEeuYBD99lzb026Yr/3k9uhckILT z5WeIwC1GuQ8AKFjrfHjeNSnPtZDBdjNQiNzJ6MaRS+xgOxYOXXrSbvOyoruLCHVLwdf o1z/M7sa+ZY7gs3a5XWkcn9QTm+U6ekV5yWBeuJPLk57+cuKp7/a44EJwbb1OAO1qXZ5 RRRQ== X-Gm-Message-State: ACrzQf3mE0ivnv/fyLzF1Ed8c6cib1BqrA0639QpcEfDKu7YeqwsmyPB Ef7cfiLn4hsvBn7t2ySOT6Q= X-Google-Smtp-Source: AMsMyM7eZofAjeHWzJ94vO88RDrBbxJwmqGvA2+l5nKX+AFUaM4MF83Mofo0oOBLql0h1YnbJ4S/fg== X-Received: by 2002:a63:5658:0:b0:43c:dac:9e24 with SMTP id g24-20020a635658000000b0043c0dac9e24mr9915160pgm.562.1666001089618; Mon, 17 Oct 2022 03:04:49 -0700 (PDT) Received: from localhost.localdomain (124244014158.ctinets.com. [124.244.14.158]) by smtp.gmail.com with ESMTPSA id d8-20020a170902cec800b0017f7b6e970esm6248454plg.146.2022.10.17.03.04.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Oct 2022 03:04:49 -0700 (PDT) From: Hoi Pok Wu To: jaegeuk@kernel.org, chao@kernel.org Cc: Hoi Pok Wu , linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, syzbot+035a381ea1afb63f098d@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com Subject: [PATCH] fs: f2fs: fix kernel discard_thread NULL dereference Date: Mon, 17 Oct 2022 18:04:37 +0800 Message-Id: <20221017100437.618363-1-wuhoipok@gmail.com> X-Mailer: git-send-email 2.38.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Pointer discard_thread is pointing to nowhere, using IS_ERR prevents the situation. IS_ERR also seen being used throughout the file. Link: https://syzkaller.appspot.com/bug?id=3D9499bc6574cea5940e48199c2fd073= 2d9b11e5e1 Reported-by: syzbot+035a381ea1afb63f098d@syzkaller.appspotmail.com Signed-off-by: Hoi Pok Wu --- fs/f2fs/segment.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index acf3d3fa4363..79978b7206b5 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -1634,7 +1634,8 @@ void f2fs_stop_discard_thread(struct f2fs_sb_info *sb= i) struct task_struct *discard_thread =3D dcc->f2fs_issue_discard; =20 dcc->f2fs_issue_discard =3D NULL; - kthread_stop(discard_thread); + if (!IS_ERR(discard_thread)) + kthread_stop(discard_thread); } } =20 --=20 2.38.0