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 12CC1558BB for ; Thu, 12 Dec 2024 14:16:35 +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=1734012996; cv=none; b=etcLlXMwhlStbaBlOlz3MK/l2VbkH4bsaUmHL8RCNOILBE/ZpkjWYXH85upTnQbU7MBxSf5whqE2UX6Wf6sFtcmI/FU//r8x+co3ZjdvEXfdDwZjHs6Lh6cdeBCGDXq6c7bceSIEjGCX/BR1BkEi0uWMpJYqnwREcyzBtFHsytc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734012996; c=relaxed/simple; bh=45TZOcgzHOmBIRwi6FLlW8HAR5EeI3rFfCok//EusG4=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=nSwwKZOcBgBcOU4Mn9073BYX2+D8rePuwfmiD9rbJYP8K28BlwyxQpaTN6uxQ0LQukQqHRDw2PWFN+zdqD04vsVCJqNDpW3xIwZRIysmj448VQxpUVxPKisbeMGMpYe0S5Jq3rM0VsjMZSMtqjlQwZzBTG23em+ncYokVSu49Lg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RJqzlOZi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RJqzlOZi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AAC8C4CECE; Thu, 12 Dec 2024 14:16:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734012995; bh=45TZOcgzHOmBIRwi6FLlW8HAR5EeI3rFfCok//EusG4=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=RJqzlOZiX4A4XWASQhxGbSXC+5wIHPok7A/8IPeQ/zl8mDz3hEmpPhZOuT0gPVNYi DAawO995TTkqp+bOtCYqNtQNbDh7cC0ReRTT+R4djXuR1OmALowK6z2zdn9ix2kMr0 1oVUUoUrRWJKPMMqg4zp9MQb+VhlhyrTJS51qX+ERfM+rePSKbT9XBH9ltzxgiMQws 9BxuX1qJZgllKqJ6WBF08wOvG6gbFIEmbEUhXCTKtSflh8SSkfgBadFp8G+XBdJ9+G 8CZd+ZK10lMjzDQm1Ymk8NbSX9g5DgJv6Ie3HSqfedMZrpr1d1M4hf6SJDy9U6As1R 5+qJtXt/ZYFjw== Message-ID: <88a6844e-1294-4997-8ef3-a69ff6add34d@kernel.org> Date: Thu, 12 Dec 2024 22:16:35 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: Chao Yu , LKML , syzbot+7ff87b095e7ca0c5ac39@syzkaller.appspotmail.com Subject: Re: [PATCH] erofs: fix rare pcluster memory leak after unmounting To: Gao Xiang , linux-erofs@lists.ozlabs.org References: <674c1235.050a0220.ad585.0032.GAE@google.com> <20241203072821.1885740-1-hsiangkao@linux.alibaba.com> Content-Language: en-US From: Chao Yu Autocrypt: addr=chao@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/12/3 15:28, Gao Xiang wrote: > There may still exist some pcluster with valid reference counts > during unmounting. Instead of introducing another synchronization > primitive, just try again as unmounting is relatively rare. This > approach is similar to z_erofs_cache_invalidate_folio(). > > It was also reported by syzbot as a UAF due to commit f5ad9f9a603f > ("erofs: free pclusters if no cached folio is attached"): > > BUG: KASAN: slab-use-after-free in do_raw_spin_trylock+0x72/0x1f0 kernel/locking/spinlock_debug.c:123 > .. > queued_spin_trylock include/asm-generic/qspinlock.h:92 [inline] > do_raw_spin_trylock+0x72/0x1f0 kernel/locking/spinlock_debug.c:123 > __raw_spin_trylock include/linux/spinlock_api_smp.h:89 [inline] > _raw_spin_trylock+0x20/0x80 kernel/locking/spinlock.c:138 > spin_trylock include/linux/spinlock.h:361 [inline] > z_erofs_put_pcluster fs/erofs/zdata.c:959 [inline] > z_erofs_decompress_pcluster fs/erofs/zdata.c:1403 [inline] > z_erofs_decompress_queue+0x3798/0x3ef0 fs/erofs/zdata.c:1425 > z_erofs_decompressqueue_work+0x99/0xe0 fs/erofs/zdata.c:1437 > process_one_work kernel/workqueue.c:3229 [inline] > process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3310 > worker_thread+0x870/0xd30 kernel/workqueue.c:3391 > kthread+0x2f2/0x390 kernel/kthread.c:389 > ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > > However, it seems a long outstanding memory leak. Fix it now. > > Fixes: f5ad9f9a603f ("erofs: free pclusters if no cached folio is attached") > Reported-by: syzbot+7ff87b095e7ca0c5ac39@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/r/674c1235.050a0220.ad585.0032.GAE@google.com > Signed-off-by: Gao Xiang Reviewed-by: Chao Yu Thanks,