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 B13574E9C16 for ; Thu, 17 Sep 2026 16:26:43 +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=1789662405; cv=none; b=O2SXlhGPJFZJlSrEo7ylhMg7++N9/AXkmBfjqVHH9RYLrEzWQN8Wzdz7dMrh/D4Ul4MasslfgCB97e+uCTizZlaIZDY0xMtQkA3GZsea87eaBs4y0qpf6ems33aW9bb77u/G6S4vRRQCwPv2fjV+kpHFDHfADWjMSZtBGj5E6wA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789662405; c=relaxed/simple; bh=scJqLgMlzUJ+TAhr7fvkn832LeczAEnawkhhY3ARPd8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Egb5r+m0apeXbFW4SXjUnJYRE53lAeb5eDDOA01f7ditq0QC44uc1s+WvizRKV21QF71kDZW6XbePhILU1xIOSQci3w8ZCad45527TsnCA6W12UQtws53voxad5TZI/VzGkNayQVIqzriMeCYJMx069o0ZXu2+m3RYYEeyjGKvk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QpsGG7ux; 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="QpsGG7ux" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15E011F000FF; Thu, 17 Sep 2026 16:26:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789662403; bh=O0YAwXjJFUGoUO0h0cD7LolN+9Zbw/MjSWiiwqufRyU=; h=From:To:Cc:Subject:Date:Reply-To; b=QpsGG7uxAw8h8I7wb6gRC66lYCBR9qF5ErenJQGskzVyq45sUY2a0XVYUi5q0dgyg aB7WeF+jNA8nSi/9k0c4VEExzS9D+Y2SxPN/qbKhCSYHSF67tkVdry6LR7vWct48yx 01Bt47w842rAuaWq8H8BO4qefLnSZ5grTj4H6yxg= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-90342: bpf: Fix mmap_lock deadlock on arena lock failure Date: Thu, 17 Sep 2026 17:12:52 +0100 Message-ID: <2026091702-CVE-2026-90342-d504@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=2636; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=yB7wy6RrHlztK3WjUhS5A88w6APptLmgzpuSulRaRBY=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlrBOal8C5nKJy5Z0ZCrrPi2uKwfaF9sx9+ePKk2vTkx Ht+6okXOmJZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAi+pEMC3bs5ll1cqHulNNL 8/qqfZz6NxpJqTEs6Jl2Zd3zXI/1buEST+YkVMxVe5OQCgA= 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: bpf: Fix mmap_lock deadlock on arena lock failure Reported by the Sashiko AI review. arena_vm_fault() returns VM_FAULT_RETRY when it can't take arena->spinlock, but it never took mmap_lock. The fault path assumes a VM_FAULT_RETRY handler already dropped mmap_lock and re-takes it on the retry, so mmap_lock gets taken twice and can deadlock: do_user_addr_fault() { fault = handle_mm_fault(...); // calls arena_vm_fault() if (fault & VM_FAULT_RETRY) goto retry; // re-locks mmap_lock mmap_read_unlock(mm); } Return VM_FAULT_SIGBUS instead, for two reasons: 1. We could keep VM_FAULT_RETRY, but then we'd have to drop the fault lock first and cap the retry ourselves, the way __folio_lock_or_retry() does. 2. A failed raw_res_spin_lock_irqsave() already means a possible deadlock was detected, so retrying just hits the same lock again. So returning VM_FAULT_RETRY here is overkill. The Linux kernel CVE team has assigned CVE-2026-90342 to this issue. Affected and fixed versions =========================== Issue introduced in 7.0 with commit b8467290edab4bafae352bf3f317055669a1a458 and fixed in 7.2.6 with commit af8087f16714f7620c4db3e732baaa1b2337948f Issue introduced in 7.0 with commit b8467290edab4bafae352bf3f317055669a1a458 and fixed in 7.3-rc1 with commit 0b10b945479c954393d62ee3229d2f224a4ca91c 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-2026-90342 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: kernel/bpf/arena.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/af8087f16714f7620c4db3e732baaa1b2337948f https://git.kernel.org/stable/c/0b10b945479c954393d62ee3229d2f224a4ca91c