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 4F1FC36CDEF; Tue, 6 Jan 2026 17:58:41 +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=1767722321; cv=none; b=Uo8jQK5xcYMzocbCQOqZAfl0TrrBb8KUtzUY8zeEHlVNvwpWYuOhvoG21jJpKDRn/BwlsrGu4tb2PIiMBhjBlZ7JSjmoFwuNlHDxvu+8v/q1yXiP+vRmVNniCeEC7Mzeh+Lo6d2ZVLiaCCmQqAJhIWrieHAB9oTIOOdAYWVAuO4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767722321; c=relaxed/simple; bh=ZZAPzfF0b7QoNN0LoQrwjCKSoUG4bfBTnz3WVOMxHSA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=EqMoogDmnunPpVc3lO1FSt1/MlEy6tfcDxLcAkb3xongXEfVNm4/tfAnruBZVH7rKE1lr6qoqCTnhTofoa98/ONt+CjldxA9WOH2/MNxm/zPvIrAs23K8pEnPZmqZgC4J3CdVrhI+Os6x/0d9DadIW9jPTmTOVzYfcA8SOcl6UM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=SI8VJyu0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="SI8VJyu0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0133C116C6; Tue, 6 Jan 2026 17:58:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767722321; bh=ZZAPzfF0b7QoNN0LoQrwjCKSoUG4bfBTnz3WVOMxHSA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SI8VJyu0Ubs26HMRNwLXIh/gqoAS9dVZUXGnkzJJUg3QjsXwXKzZfocelHlCarfMr k85PU2N8wFaveCAGHSvenIk3yr7IKJf0tJA8hHRAnz+6l4wwsR0JYN6eIf0Po/lRjp tbszYxWvnh+rj6Y2nRR5VNzQ/IlCrHogGVv53ssg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Matthew Wilcox (Oracle)" , Jan Sokolowski , Koen Koning , Peter Senna Tschudin , =?UTF-8?q?Christian=20K=C3=B6nig?= , Andrew Morton Subject: [PATCH 6.18 228/312] idr: fix idr_alloc() returning an ID out of range Date: Tue, 6 Jan 2026 18:05:02 +0100 Message-ID: <20260106170556.101146394@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260106170547.832845344@linuxfoundation.org> References: <20260106170547.832845344@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthew Wilcox (Oracle) commit c6e8e595a0798ad67da0f7bebaf69c31ef70dfff upstream. If you use an IDR with a non-zero base, and specify a range that lies entirely below the base, 'max - base' becomes very large and idr_get_free() can return an ID that lies outside of the requested range. Link: https://lkml.kernel.org/r/20251128161853.3200058-1-willy@infradead.org Fixes: 6ce711f27500 ("idr: Make 1-based IDRs more efficient") Signed-off-by: Matthew Wilcox (Oracle) Reported-by: Jan Sokolowski Reported-by: Koen Koning Reported-by: Peter Senna Tschudin Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6449 Reviewed-by: Christian König Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- lib/idr.c | 2 ++ tools/testing/radix-tree/idr-test.c | 21 +++++++++++++++++++++ 2 files changed, 23 insertions(+) --- a/lib/idr.c +++ b/lib/idr.c @@ -40,6 +40,8 @@ int idr_alloc_u32(struct idr *idr, void if (WARN_ON_ONCE(!(idr->idr_rt.xa_flags & ROOT_IS_IDR))) idr->idr_rt.xa_flags |= IDR_RT_MARKER; + if (max < base) + return -ENOSPC; id = (id < base) ? 0 : id - base; radix_tree_iter_init(&iter, id); --- a/tools/testing/radix-tree/idr-test.c +++ b/tools/testing/radix-tree/idr-test.c @@ -57,6 +57,26 @@ void idr_alloc_test(void) idr_destroy(&idr); } +void idr_alloc2_test(void) +{ + int id; + struct idr idr = IDR_INIT_BASE(idr, 1); + + id = idr_alloc(&idr, idr_alloc2_test, 0, 1, GFP_KERNEL); + assert(id == -ENOSPC); + + id = idr_alloc(&idr, idr_alloc2_test, 1, 2, GFP_KERNEL); + assert(id == 1); + + id = idr_alloc(&idr, idr_alloc2_test, 0, 1, GFP_KERNEL); + assert(id == -ENOSPC); + + id = idr_alloc(&idr, idr_alloc2_test, 0, 2, GFP_KERNEL); + assert(id == -ENOSPC); + + idr_destroy(&idr); +} + void idr_replace_test(void) { DEFINE_IDR(idr); @@ -409,6 +429,7 @@ void idr_checks(void) idr_replace_test(); idr_alloc_test(); + idr_alloc2_test(); idr_null_test(); idr_nowait_test(); idr_get_next_test(0);