From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 D32C84D795F for ; Thu, 17 Sep 2026 16:22:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789662156; cv=none; b=Ji+8F9/vcBgAHRu9ybsCKjnLCNKp1ZDjhj/VeAAlnAKr0YksfXrLuqlJ9m6ETMZMek4+ahXlbpr7vuQqyXy5pqjEQtT6dupAocjycf9grqUHIbocRSDRrOFXIo/49kn3IOn5yo/Hge5j64Im3OSTXjpVdEYMz2fs59ed0bJKnQE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789662156; c=relaxed/simple; bh=M+vTighQCQUobUI93HhDaKGkDvLmOGzKZyN3SPwYRho=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=I+3eY4/GQ86byMkHSPtxo7p533U7vZI3zW0pfoWGMVA5A3jzmG91e3lRQjKgND7yRsuNPLTnBiwenLjegO/fEX+HjIFFF/tOgdbwIhWFLuIppKguuMBd3B8Wn1fxLLJaiar+EJrB4UKnajrkm621T77LAZuoeZsram71WmnF5fU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cXlyguNy; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="cXlyguNy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A7761F000FF; Thu, 17 Sep 2026 16:22:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789662154; bh=h/w0+aCJGmogAwtx72cOQfV93uliToqWtllLuLoHMUA=; h=From:To:Cc:Subject:Date:Reply-To; b=cXlyguNyjTbm/8Z+50KKYSFZjYqkKGxa/4YlDVy82SecxrIB4XE1R54H6jyWGRjG+ KZcCA8XgtrW0V7T3nQiFeJ3DDW6vweMB8dQ5/OMWTiP5gWkkIDPSoJKOKwSMlWa7/c xm+ke0Mqi0lEDwX6ELzgnmA82bVSw9B488U9Ey34= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-90260: btrfs: zoned: don't clobber the extent buffer when zeroing it out Date: Thu, 17 Sep 2026 17:11:30 +0100 Message-ID: <2026091746-CVE-2026-90260-15ea@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3064; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=2Xo5gl5h/DHBHTKLgL/YYsc/erSY6ouH1btvOVWVbBY=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlrBPperTa+tzXJcPWn508dND/qL+HxPiTwW/3FZJbbK tM6z9zr74hlYRBkYpAVU2T5so3n6P6KQ4pehranYeawMoEMYeDiFICJhN9kWDClWbD+ov4tjYDu Jy8vWt9ZzJ0RPYFhwbTUP1wXbd/Y9/1eG2y8+xv3s9OeOQA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: don't clobber the extent buffer when zeroing it out On a zoned filesystem a freed-but-still-dirty tree block is written out as zeros (EXTENT_BUFFER_ZONED_ZEROOUT) only to keep the zone write pointer advancing. btree_csum_one_bio() implemented this by memzeroing the extent buffer's own folios before submission. That destroys the in-memory buffer while it may still be referenced. In particular btrfs_free_tree_block() can run on it afterwards and reads the header to add a delayed reference; once the header has been zeroed it frees bytenr 0 and corrupts the extent tree (the btrfs_header_bytenr(buf) != 0 ASSERT in btrfs_free_tree_block(), or an "unable to find ref" abort). It is flaky and reproduces under fsstress, e.g. generic/461 and generic/013. Write the zeros to disk from the shared zero page instead and leave the extent buffer content untouched, so any later reference - including the delayed reference from btrfs_free_tree_block() - still sees a valid header. end_bbio_meta_write() now clears writeback on the buffer's own folios, as the bio no longer carries them. The Linux kernel CVE team has assigned CVE-2026-90260 to this issue. Affected and fixed versions =========================== Issue introduced in 6.8 with commit aa6313e6ff2bfbf736a2739047bba355d8241584 and fixed in 6.18.52 with commit 92484ad014f2e2b0e0e7bbc1610951e978cf557c Issue introduced in 6.8 with commit aa6313e6ff2bfbf736a2739047bba355d8241584 and fixed in 7.2.6 with commit 98e3747587f9f87f010d8d7e55786216249a94af Issue introduced in 6.8 with commit aa6313e6ff2bfbf736a2739047bba355d8241584 and fixed in 7.3-rc1 with commit db4b9eefc8ee0bcaeee4d5e6a7313905f6a2fe7c Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-90260 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: fs/btrfs/disk-io.c fs/btrfs/extent_io.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/92484ad014f2e2b0e0e7bbc1610951e978cf557c https://git.kernel.org/stable/c/98e3747587f9f87f010d8d7e55786216249a94af https://git.kernel.org/stable/c/db4b9eefc8ee0bcaeee4d5e6a7313905f6a2fe7c