From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f48.google.com (mail-wr1-f48.google.com [209.85.221.48]) (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 1724C2F7463 for ; Thu, 16 Oct 2025 07:09:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760598556; cv=none; b=bXT6TDskIWfXpXtcHfcaUfmjUxm2cEWALGR8hWywrM054RcTEBF1szmWm6h9b28qZED4wMdkgb7FWql7XStMt9xvbyNjNQmkkpZ+h+NW3wOYU18wEJLGNhguBFuDrYwUNYaz9f/0uGV+DEITw7w7SnCDsNB69ibDNCZyW5keZVg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760598556; c=relaxed/simple; bh=5nHvZamFEkH9EvPLMXQNlxC9Wmfg98It5AsesLKv6IA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cZ2MQp70TafK0ezdUvjR3D9350oYrlQAIhiKmEneCV48KSWkZHj1bQl4GVTI6pWTq7jJI0OD5tTLYPD+bLlY3tRG4HZmqfZPQVIq0+v8O1wt0LSZ2OlrHQ4QcYJ/uGpffKABnZ4aqBGSX6bst/lw5Oz3UK0oBaSVZ/xGJS3R+eM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=VPXkkEgK; arc=none smtp.client-ip=209.85.221.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="VPXkkEgK" Received: by mail-wr1-f48.google.com with SMTP id ffacd0b85a97d-427015003eeso116670f8f.0 for ; Thu, 16 Oct 2025 00:09:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1760598551; x=1761203351; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=mSIMe5l7UI5vEmVvxSYex6af8FroTpoooyg2xvpjJIA=; b=VPXkkEgKEMfDprue6Y7x6YrDDLHmf5xRxdo6nR+Dvr1jfATXn0FyD3o+5KddxxtpuI OJSrDimp2j7UPHe7E64jcFtHSeTB3peCDFKbSS0Q4yDzJjFGcz7vSJjyrBVed8r5q5iA 5l9lD0Mz3DwHxuXlcOnjcdbhc3X+m9R4b/8hCVVZwRw0qeAtGbgT+wlnKJh9JwYuMSft Ph2rKHRTF12wzaL41q5Ak3q+QsHWf2+tHcTCLucDv5c1/WbvYiWcv5hH1WRdiP7KJrAY /moyDk3dBvt2SNr+muqeS0VXZ1+/AMTToo1llrgFEt1PZ3SLwL1crdSqQF2wCMo0Xsae 1TVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760598551; x=1761203351; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=mSIMe5l7UI5vEmVvxSYex6af8FroTpoooyg2xvpjJIA=; b=Co0RyidZ0M3tadtJWncA2MY96DsviJ/IpIEkEf51GO1DheaBxpX/had0R1tlo/X1q6 qlV/ghFEA+i8VzLS+ZoS0SxMKC3iHI1/uCxny/c6BIskO5TZOFip8mmuxThk9QGT/0a4 Su7oxtwZJC28iGWkZihqFdcE7F2qJBQ3yGayBasJRcD4kl5tQxZbFb0HcpLOQehBu16L YH+hJhn+ovZuDfghErY8IL95kzVZ7m1MahC7/T5FsnQT0YZZ0Vv6oKdppVsCMkr2XaUy G9zFqY45u60////TI8TctZ6bcq3xmHrgPycOFKfnXJ9Adu+Qwmx37rUzbVpHMS9J4IfB G6Rg== X-Forwarded-Encrypted: i=1; AJvYcCXCvaXGyzqOzUIqGRMq5zUl2DD7ojRf0jHgZWwrVn/ITtnuIAqzdMzLIXIWovm8PwdhSB7rmfUux7Oa3s0=@vger.kernel.org X-Gm-Message-State: AOJu0Yy9odREH3WbwN+8a9zpaRpGBPGIyXFssWr/FFO7UXd1sq15hoVO yBkFVFepJOIHuHHvj6rT06p9sxiLCs+MgcEB5syiIb5VxrPGPl3q4hYptjb5GLHLstc= X-Gm-Gg: ASbGncvWGE3GGBwnCmMyDJbxKg8dXPa2YYrS/EqU7q3SixvnUL1aKxYUn8myWl2wGUn 11wmEcQw/T+AO804wqqQwsInbIPKXQ/jP0w+Dbg3Au8rhA3+cNcPtxzvh2QiqKeOvpzBrregfaR +1qcDGrDAQv91D+8UfQPi+KWYSgfBCX7WX1zVQyu2wnONdzaMzlp57mlhjsC1ZFj8lmqa9OzOuN St8WYObpS4cO+wXHcX1iFT7VV7fYt/pgTcolPzb/PvkkV2wRM0tMtsmaEIbwP+rQNgLC2dDIxtm AXiPUxCFxRu/+McgQWrTvGV730z2LBeXEc2xKgMjUMSoVOelG36RBYXnEMY1m/+fMGMl59cMPiE J51XMxxouMRXyWi1MAEU2PcmYVHvFPoa6UdTGipGPmmQSLs0PqCAhPJ99mG//utHaXA1W/rzJ3w Kk3h8/zpZ+9a8B8ijGUDhlkkn3hzNh X-Google-Smtp-Source: AGHT+IG3xHOgjpo7n0eMc01/ows8fVl/W9nPPptegztBLolxI1Z7VulTw5HECk2nkQioT21JP/vihw== X-Received: by 2002:a5d:5f43:0:b0:427:151:3d9c with SMTP id ffacd0b85a97d-42701514223mr500660f8f.16.1760598551320; Thu, 16 Oct 2025 00:09:11 -0700 (PDT) Received: from ?IPV6:2403:580d:fda1::299? (2403-580d-fda1--299.ip6.aussiebb.net. [2403:580d:fda1::299]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-29099314ceesm18941095ad.16.2025.10.16.00.09.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 16 Oct 2025 00:09:10 -0700 (PDT) Message-ID: <51c7108b-19ab-499a-afdc-14e4a00431db@suse.com> Date: Thu, 16 Oct 2025 17:39:06 +1030 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] btrfs: Fix NULL pointer access in btrfs_check_leaked_roots() To: Dewei Meng , clm@fb.com, dsterba@suse.com, quwenruo.btrfs@gmx.com Cc: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, Daniel Vacek References: <20251016061011.22946-1-mengdewei@cqsoftware.com.cn> Content-Language: en-US From: Qu Wenruo Autocrypt: addr=wqu@suse.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNGFF1IFdlbnJ1byA8d3F1QHN1c2UuY29tPsLAlAQTAQgAPgIbAwULCQgHAgYVCAkKCwIE FgIDAQIeAQIXgBYhBC3fcuWlpVuonapC4cI9kfOhJf6oBQJnEXVgBQkQ/lqxAAoJEMI9kfOh Jf6o+jIH/2KhFmyOw4XWAYbnnijuYqb/obGae8HhcJO2KIGcxbsinK+KQFTSZnkFxnbsQ+VY fvtWBHGt8WfHcNmfjdejmy9si2jyy8smQV2jiB60a8iqQXGmsrkuR+AM2V360oEbMF3gVvim 2VSX2IiW9KERuhifjseNV1HLk0SHw5NnXiWh1THTqtvFFY+CwnLN2GqiMaSLF6gATW05/sEd V17MdI1z4+WSk7D57FlLjp50F3ow2WJtXwG8yG8d6S40dytZpH9iFuk12Sbg7lrtQxPPOIEU rpmZLfCNJJoZj603613w/M8EiZw6MohzikTWcFc55RLYJPBWQ+9puZtx1DopW2jOwE0EWdWB rwEIAKpT62HgSzL9zwGe+WIUCMB+nOEjXAfvoUPUwk+YCEDcOdfkkM5FyBoJs8TCEuPXGXBO Cl5P5B8OYYnkHkGWutAVlUTV8KESOIm/KJIA7jJA+Ss9VhMjtePfgWexw+P8itFRSRrrwyUf E+0WcAevblUi45LjWWZgpg3A80tHP0iToOZ5MbdYk7YFBE29cDSleskfV80ZKxFv6koQocq0 vXzTfHvXNDELAuH7Ms/WJcdUzmPyBf3Oq6mKBBH8J6XZc9LjjNZwNbyvsHSrV5bgmu/THX2n g/3be+iqf6OggCiy3I1NSMJ5KtR0q2H2Nx2Vqb1fYPOID8McMV9Ll6rh8S8AEQEAAcLAfAQY AQgAJgIbDBYhBC3fcuWlpVuonapC4cI9kfOhJf6oBQJnEXWBBQkQ/lrSAAoJEMI9kfOhJf6o cakH+QHwDszsoYvmrNq36MFGgvAHRjdlrHRBa4A1V1kzd4kOUokongcrOOgHY9yfglcvZqlJ qfa4l+1oxs1BvCi29psteQTtw+memmcGruKi+YHD7793zNCMtAtYidDmQ2pWaLfqSaryjlzR /3tBWMyvIeWZKURnZbBzWRREB7iWxEbZ014B3gICqZPDRwwitHpH8Om3eZr7ygZck6bBa4MU o1XgbZcspyCGqu1xF/bMAY2iCDcq6ULKQceuKkbeQ8qxvt9hVxJC2W3lHq8dlK1pkHPDg9wO JoAXek8MF37R8gpLoGWl41FIUb3hFiu3zhDDvslYM4BmzI18QgQTQnotJH8= In-Reply-To: <20251016061011.22946-1-mengdewei@cqsoftware.com.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2025/10/16 16:40, Dewei Meng 写道: > If fs_info->super_copy or fs_info->super_for_commit allocated failed in > btrfs_get_tree_subvol(), then no need to call btrfs_free_fs_info(). > Otherwise btrfs_check_leaked_roots() would access NULL pointer because > fs_info->allocated_roots had not been initialised. > > syzkaller reported the following information: > ------------[ cut here ]------------ > BUG: unable to handle page fault for address: fffffffffffffbb0 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 64c9067 P4D 64c9067 PUD 64cb067 PMD 0 > Oops: Oops: 0000 [#1] SMP KASAN PTI > CPU: 0 UID: 0 PID: 1402 Comm: syz.1.35 Not tainted 6.15.8 #4 PREEMPT(lazy) > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), (...) > RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] > RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] > RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline] > RIP: 0010:refcount_read include/linux/refcount.h:170 [inline] > RIP: 0010:btrfs_check_leaked_roots+0x18f/0x2c0 fs/btrfs/disk-io.c:1230 > [...] > Call Trace: > > btrfs_free_fs_info+0x310/0x410 fs/btrfs/disk-io.c:1280 > btrfs_get_tree_subvol+0x592/0x6b0 fs/btrfs/super.c:2029 > btrfs_get_tree+0x63/0x80 fs/btrfs/super.c:2097 > vfs_get_tree+0x98/0x320 fs/super.c:1759 > do_new_mount+0x357/0x660 fs/namespace.c:3899 > path_mount+0x716/0x19c0 fs/namespace.c:4226 > do_mount fs/namespace.c:4239 [inline] > __do_sys_mount fs/namespace.c:4450 [inline] > __se_sys_mount fs/namespace.c:4427 [inline] > __x64_sys_mount+0x28c/0x310 fs/namespace.c:4427 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0x92/0x180 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > RIP: 0033:0x7f032eaffa8d > [...] > > Fixes: 3bb17a25bcb0 ("btrfs: add get_tree callback for new mount API") > Signed-off-by: Dewei Meng > Reviewed-by: Daniel Vacek Now pushed into for-next branch. Thanks, Qu > --- > V1 -> V2: > - Revise the patch description to make it easier to read > - Delete btrfs_free_fs_info() when super_copy/super_for_commit allocated > failed, instead of NULL pointer check in btrfs_check_leaked_roots() > > fs/btrfs/super.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index d6e496436539..dc95e697b22b 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -2069,7 +2069,9 @@ static int btrfs_get_tree_subvol(struct fs_context *fc) > fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL); > fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL); > if (!fs_info->super_copy || !fs_info->super_for_commit) { > - btrfs_free_fs_info(fs_info); > + kfree(fs_info->super_copy); > + kfree(fs_info->super_for_commit); > + kvfree(fs_info); > return -ENOMEM; > } > btrfs_init_fs_info(fs_info);