From nobody Fri Dec 19 11:28:09 2025 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6AD68314A9E for ; Mon, 8 Dec 2025 09:45:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765187157; cv=none; b=TDk3JA4MJ3pRq92tEWkkxKrlOM/iOwPwdJhgSKRulEdvjUtzwW1135ZgpfTSOzh1LiwnxVWKDM6W/W34sAncFWaP/NbP6vLC2cjagA+ueydvB53HwEqwhzDT5Kib6IfTPSBGlrqdILWNYz0qSoiaRLR0rgd1kEIYpRbDFCDBpaA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765187157; c=relaxed/simple; bh=iwdS35ruxh+CQ0wzK51flFZg8LwrqaXCRYKeR/6KPdU=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=eNJBHkvd4y8COPlItRjOlTJ7lzoicaQ6jSuiWyc1s2Php8+gT8HyTRzRKkqplOpRvpW7K8aqJ1E1BO+KXK6zBfdYVUokVYLo/5sJcqdf/CrqUnIN7JAO3b3u7iMoMIFn9Ge2V1MKRs+I/tohEaC6PIlYpX/Rr4jbnzYnke7Gw1U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--kuniyu.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=B5v+WoR8; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--kuniyu.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="B5v+WoR8" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-3436e9e3569so7886648a91.2 for ; Mon, 08 Dec 2025 01:45:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1765187154; x=1765791954; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=oyQ3Z7L0tbtR/Vc5G2GUEzfAk7Kgz5Xk0vB09voKDpk=; b=B5v+WoR8g3Ssy9ZIUt3luGcsvqeV3hWNKMO7GEpjG8AVeid6W+t/4Y1YNI1ECMqaaQ nNC6SDFRUGSSSrd2nPLRgP5mRBMaWKdvjTkS5uc3E/nnlwa5Pnp3fwaQ+6Bgs+bpln2T eFgDn6ve5LLaUAO+XP5/bXHQy2ry5etwJ6mHluRhXLoYP3PWGKVnKwJbmujJTgkl5k/4 QNYmhRmba1+LTxI0VdKxKLn+06z74LgXMsM9dCMgL+PHgtbkXzwfQuAXzdq9z7x7+oV+ Nz6tDZ+1OrsI78K9jhz/tsCq4dcE3hkxM4zfHH++676rzxxR6sfbpSndZlpTcAIdpCve jf1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1765187154; x=1765791954; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=oyQ3Z7L0tbtR/Vc5G2GUEzfAk7Kgz5Xk0vB09voKDpk=; b=IhsnduDbl6Y5KIWEZSNeQHAYVVtKe1RAVFL7s8CmeWd71obKUN/XgwBlAUixStp69w mBOrDovzX0fZmk0vngqRVsT3g3B3wAuUylc/GUov6UzPRmKczynhkSXkobEcW18pEQ7S v4y8wNbQaFbrkboCmCPAKG0YszYngTARHga8eRwMgJyGHMiFm85Wvh7WP6UTSTRVbc77 ss6VFc7jdPO5LKEsfvG6oLmUtcaloOvd2mJOJC7ZlkQagm4gVwLofqXltmfdHrHoI6WB w1Xii7ACWbTjxQrm033wIFIvG+JGA71n44pXUmTz7m/Ob2/JhjGAAua0FsuOsGLsyjY2 Za+A== X-Forwarded-Encrypted: i=1; AJvYcCXpwmEeXihfhzDgrlpx4cva4iYD57ZJJI2qh1lTB1tVB2DKbAvtsfYq9Fx+TWasDLnZGVbRAectvwHhr0w=@vger.kernel.org X-Gm-Message-State: AOJu0Yz51YWzIknr2PyPdgw0MdYpN8radBNEWz5NBnHjIc9oqWEmRVjw FV8M1S/qWUrUU0boBFPEeF7LNJdBJ7BPthjfl9R0QAUfKo2LoUe172NBNKnGkZKcb5k2swyw8xJ 5v+VAFw== X-Google-Smtp-Source: AGHT+IGyeuFqZfaYS0X1hBaKujlHCpYV4GWrWw1AHZ8QzOEk4wKIZZnllI9SeYwfekhsFfYFc55NHTBwWN8= X-Received: from pjwx12.prod.google.com ([2002:a17:90a:c2cc:b0:349:4e4c:f317]) (user=kuniyu job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:3b41:b0:341:8ae5:fde5 with SMTP id 98e67ed59e1d1-349a25be018mr6351020a91.18.1765187154315; Mon, 08 Dec 2025 01:45:54 -0800 (PST) Date: Mon, 8 Dec 2025 09:45:45 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.52.0.223.gf5cc29aaa4-goog Message-ID: <20251208094551.46184-1-kuniyu@google.com> Subject: [PATCH] debugfs: Fix memleak in debugfs_change_name(). From: Kuniyuki Iwashima To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Christian Brauner Cc: NeilBrown , Kuniyuki Iwashima , Kuniyuki Iwashima , linux-kernel@vger.kernel.org, syzbot+3d7ca9c802c547f8550a@syzkaller.appspotmail.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" syzbot reported memleak in debugfs_change_name(). [0] When lookup_noperm_unlocked() fails, new_name is leaked. Let's fix it by reusing to kfree_const() at the end of debugfs_change_name(). [0]: BUG: memory leak unreferenced object 0xffff8881110bb308 (size 8): comm "syz.0.17", pid 6090, jiffies 4294942958 hex dump (first 8 bytes): 2e 00 00 00 00 00 00 00 ........ backtrace (crc ecfc7064): kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5258 [inline] __do_kmalloc_node mm/slub.c:5651 [inline] __kmalloc_node_track_caller_noprof+0x3b2/0x670 mm/slub.c:5759 __kmemdup_nul mm/util.c:64 [inline] kstrdup+0x3c/0x80 mm/util.c:84 kstrdup_const+0x63/0x80 mm/util.c:104 kvasprintf_const+0xca/0x110 lib/kasprintf.c:48 debugfs_change_name+0xf6/0x5d0 fs/debugfs/inode.c:854 cfg80211_dev_rename+0xd8/0x110 net/wireless/core.c:149 nl80211_set_wiphy+0x102/0x1770 net/wireless/nl80211.c:3844 genl_family_rcv_msg_doit+0x11e/0x190 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x2fd/0x440 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x93/0x1d0 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x3a3/0x4f0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x335/0x6b0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:733 [inline] ____sys_sendmsg+0x562/0x5a0 net/socket.c:2608 ___sys_sendmsg+0xc8/0x130 net/socket.c:2662 __sys_sendmsg+0xc7/0x140 net/socket.c:2694 Fixes: 833d2b3a072f7 ("Add start_renaming_two_dentries()") Reported-by: syzbot+3d7ca9c802c547f8550a@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69369d82.a70a0220.38f243.009f.GAE@googl= e.com/ Signed-off-by: Kuniyuki Iwashima --- fs/debugfs/inode.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 4b263c328ed29..4005d21cf009c 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -841,8 +841,10 @@ int __printf(2, 3) debugfs_change_name(struct dentry *= dentry, const char *fmt, . rd.new_parent =3D rd.old_parent; rd.flags =3D RENAME_NOREPLACE; target =3D lookup_noperm_unlocked(&QSTR(new_name), rd.new_parent); - if (IS_ERR(target)) - return PTR_ERR(target); + if (IS_ERR(target)) { + error =3D PTR_ERR(target); + goto out_free; + } =20 error =3D start_renaming_two_dentries(&rd, dentry, target); if (error) { @@ -862,6 +864,7 @@ int __printf(2, 3) debugfs_change_name(struct dentry *d= entry, const char *fmt, . out: dput(rd.old_parent); dput(target); +out_free: kfree_const(new_name); return error; } --=20 2.52.0.223.gf5cc29aaa4-goog