From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-vs1-f53.google.com (mail-vs1-f53.google.com [209.85.217.53]) (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 D0B4135F199 for ; Fri, 31 Jul 2026 06:17:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.217.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785478640; cv=none; b=j9ci7fuXrq5295C0FtZbZKOFeCqvJNSgNenGjXDOxEtHLAha8D4+J5G9DsV6ag1tL/2ESLUOdcIMjQRgUDoAZfT1k110TIRIsm1D0sEBIuP3x4rCDHtx+LMKQb86LeiVHW8yQcVGC1fVpLDJI95VqM4RGzJX1sfbzrLyiG9FQog= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785478640; c=relaxed/simple; bh=+5QYk5EiYjuebP9ZG2Pg7OKoEiKdDmMnOGBCN99Tbpo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=gzEkn2SUz5X+yjuMyVdkYvPeIbqyw5Nsu9ZqvtxiLHIJ3vnUaqi/u456zisgnz2SHqRy8u68H/IydpEL8icc82Sr3isvW6pkCHhGHDv5+bwdGWn5Jfq/Ab2qwK2RA2N/r4falWF1Td0seHQoOcjUBzp4dti4jecEpCfz/BjpEVk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=UjzbeKiU; arc=none smtp.client-ip=209.85.217.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UjzbeKiU" Received: by mail-vs1-f53.google.com with SMTP id ada2fe7eead31-75738fcb0d9so134457137.0 for ; Thu, 30 Jul 2026 23:17:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785478638; x=1786083438; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=iHW4TV4tTuaZdEfu4Qe5VuaxQkpgoHCigu/4rFxdTdg=; b=UjzbeKiUJwM3l/C6HuTTH19R6n8k56k4noBlFNP3nbXyCQbrnp+F1Q6uJqJhc1tEZd h7TLoW3vJYb7xJG99QjQ42pDVqgMVKy+F8VG9PiqyVpu0GcXhBg2446j2AnB+dNhPIxF edAvCcKbL4Rs1np11qqQ2+mgAqLslTgYdIE5NQifwiH0bzKLJU1BeLu8nTiDhQ4U/K1B KG/J9pREALbyQw43/SI6zEbjC8/QGU5xNARqH7kReuTDaDEd/pBFCGP4DsKDvcx0MIWF n6TSlwAY3GE6s2kyREYt2DBm9W6GHWub3cT9vLhedEilSjrrtdiFIb5rObr3R2t14V5F 8NjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785478638; x=1786083438; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=iHW4TV4tTuaZdEfu4Qe5VuaxQkpgoHCigu/4rFxdTdg=; b=KgyuXQpF7uHo+mV8J7kBDOthlQjVYWO+HLU7qTtgeHCtBSfUDLrX20cECkNoeAD5WY 8ASnVD6FuzkN/qhsSil9aq0K6uSu0PgASwPN9wSTXn+ijkEKsg2waR7Kz2gQPrGHG2Uo G7rky+5TnZJgI3w28D7LTQHocqcKleN6wx9rUmAyehcHcwR0tzwKC3httgpjRPidzBkY 6zb6yja5r4Apa1A9CYwbKMtCQDOLg70pWIlOcxjY9+J5OIYmqzoE4vVtHhgAmMrCu2KW rWa2P2c5kbjdy6rQlvf4o+EZ2V/8WAZ8l1+m44AQvmnCstd3MKBvvJh6N9QSHBBok96x wGuQ== X-Forwarded-Encrypted: i=1; AHgh+Rp4nvhprEFUhdcxRSnem+RxCzv2Xw9wnkvLn7StaRRWxQdVWyz5A9iUcT+2v3kfQLjUeAlcSCWxOVg/yzo=@vger.kernel.org X-Gm-Message-State: AOJu0YxypjyidanBboTWwRKqkaNMoeahAvcRZ/Xbsnfao8GRvOvhnV6H wHdHt+XEfzjEJaZGDogwgsa7uskHN96VWkH2Zv2qIRneCjn9JK8XHXbY X-Gm-Gg: AR+sD11p/QZUJ7h2Y8nMq6e4Aq3FZSmVZtkO8M8K8KiZ7WpoowxlXlJmhLDytq/tAl/ KCq+E1xosyZVzvBe3V/9uu1A5gvon2C1jwRZk/ehgmtyU9j/TNSEHhZMNjbH4QOirirnkOewjJy rLdpmoeCY//nP6vXtMKO9UeToTwObz/0Gy2d0TFhQ0nQw5OqkHdapnaP6ubRMhHdSSNMmIZGHq6 k2mhUIqHx2Q88939S7l19ZhSyBifg6UYHuwL4jJ+k9G1aS8VG4F2A7py7IyDYbA5rPWfEApq/eM gMY/J08xTIO5TZkgv4whz68rdAVgvvbJK58MtXFAoVQeu+5S5El59DrKm3kec7LwHfsD/IdX8fw GceNkgwW9tGoe/OeFRczZQw0Xyb/KBh8zueHQ/dCFIPjmmBGoyiYdPwyFV9rDXFwSUmqZ9feRFP sILGgGdBvo1eCF3OLlwvdIaHp6qxPaO2dk/L7ApMe8FCY+949xCov1T3kzCmCb+vvXPw== X-Received: by 2002:a05:6102:38ce:b0:74c:9177:35bc with SMTP id ada2fe7eead31-758f6974abdmr203607137.2.1785478637579; Thu, 30 Jul 2026 23:17:17 -0700 (PDT) Received: from fedora ([2804:1b3:a8c3:8ee5:1c39:64d9:e257:73dc]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-977e6aa5d2csm62806241.12.2026.07.30.23.17.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jul 2026 23:17:16 -0700 (PDT) From: Marcelo Mendes Spessoto Junior To: Carlos Maiolino Cc: linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, Marcelo Mendes Spessoto Junior , syzbot+4e6ee73c0ae4b6e8753f@syzkaller.appspotmail.com Subject: [PATCH] xfs: add guard before freeing buffer log item Date: Fri, 31 Jul 2026 03:14:48 -0300 Message-ID: <20260731061448.192010-1-marcelomspessoto@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit A buffer's write completion can race with the CIL walking the same checkpoint's item list during a forced shutdown's simulated commit callbacks. Whichever side reaches the item last should be the one to free it; right now completion frees it unconditionally, so the CIL walk can end up touching memory that's already gone. Fixes: d2fe5c4c8d25 ("xfs: rearrange code in xfs_buf_item.c") Reported-by: syzbot+4e6ee73c0ae4b6e8753f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4e6ee73c0ae4b6e8753f Tested-by: syzbot+4e6ee73c0ae4b6e8753f@syzkaller.appspotmail.com Signed-off-by: Marcelo Mendes Spessoto Junior --- fs/xfs/xfs_buf_item.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index f4c5be67826e..c86c4387f52b 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -1072,6 +1072,9 @@ void xfs_buf_item_done( struct xfs_buf *bp) { + if (atomic_read(&bp->b_log_item->bli_refcount) != 0) + return; + /* * If we are forcibly shutting down, this may well be off the AIL * already. That's because we simulate the log-committed callbacks to -- 2.55.0