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 4B25834EEF1; Tue, 16 Dec 2025 11:46:56 +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=1765885616; cv=none; b=oILNp9gKjpmIZZmx2oRUBvwhN55keHNmifnS+zgiwIqYsuH7irvvRfNqPiwwg2NtK6aO9YTvtct/4DMEaLuTfOHmkJqv0lio+B8wQ4kOQn6lK6YWabVD94C+IZVBs13NUIl/El4U+5QgGUtuqpBLUeg7bjD5vcch/68ypCHEoBw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765885616; c=relaxed/simple; bh=JlhFRIPA1BiOhAsDEjGSpu8pgBpCz7S2/gz3ciVeEsc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RvHUmpxTZSEG296QuXqF/7GdZCLSirHk8xCWPla4BusSXMf17X/RCJn3lKlpRHvtDRqGiCxGbNDnn1UABgyiJO8Br56XFRVbF7RqFLojXoFQAE2UPr3mtl2qsWQnldemxnQZnVYFJMEz4x0lJNQzFdhRG+HO7Ri0WadY+qsg1b0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=g3alAx0U; 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="g3alAx0U" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7DEDC4CEF1; Tue, 16 Dec 2025 11:46:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1765885616; bh=JlhFRIPA1BiOhAsDEjGSpu8pgBpCz7S2/gz3ciVeEsc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g3alAx0UVkJAx/i/7SDgKO1TLBWuygHcbYXlyvr5Bun3LF47iI8kENpBHocomWpM6 AVuIQVQMpUJxoYkbXQ1fzusukPhDozPUOBQLgqwI/rYYxL4T/BENGFxmGV4Aarv2VI kdhyQ2FGDjAycfadsE9ULoZzlPRsfTJPeptvMP1o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiao Ni , Yu Kuai , Li Nan , Sasha Levin Subject: [PATCH 6.17 192/507] md: avoid repeated calls to del_gendisk Date: Tue, 16 Dec 2025 12:10:33 +0100 Message-ID: <20251216111352.467532936@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251216111345.522190956@linuxfoundation.org> References: <20251216111345.522190956@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiao Ni [ Upstream commit 90e3bb44c0a86e245d8e5c6520206fa113acb1ee ] There is a uaf problem which is found by case 23rdev-lifetime: Oops: general protection fault, probably for non-canonical address 0xdead000000000122 RIP: 0010:bdi_unregister+0x4b/0x170 Call Trace: __del_gendisk+0x356/0x3e0 mddev_unlock+0x351/0x360 rdev_attr_store+0x217/0x280 kernfs_fop_write_iter+0x14a/0x210 vfs_write+0x29e/0x550 ksys_write+0x74/0xf0 do_syscall_64+0xbb/0x380 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff5250a177e The sequence is: 1. rdev remove path gets reconfig_mutex 2. rdev remove path release reconfig_mutex in mddev_unlock 3. md stop calls do_md_stop and sets MD_DELETED 4. rdev remove path calls del_gendisk because MD_DELETED is set 5. md stop path release reconfig_mutex and calls del_gendisk again So there is a race condition we should resolve. This patch adds a flag MD_DO_DELETE to avoid the race condition. Link: https://lore.kernel.org/linux-raid/20251029063419.21700-1-xni@redhat.com Fixes: 9e59d609763f ("md: call del_gendisk in control path") Signed-off-by: Xiao Ni Suggested-by: Yu Kuai Reviewed-by: Li Nan Signed-off-by: Yu Kuai Signed-off-by: Sasha Levin --- drivers/md/md.c | 3 ++- drivers/md/md.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 436aab6c5d3de..209ca3eade260 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -887,7 +887,8 @@ void mddev_unlock(struct mddev *mddev) * do_md_stop. dm raid only uses md_stop to stop. So dm raid * doesn't need to check MD_DELETED when getting reconfig lock */ - if (test_bit(MD_DELETED, &mddev->flags)) { + if (test_bit(MD_DELETED, &mddev->flags) && + !test_and_set_bit(MD_DO_DELETE, &mddev->flags)) { kobject_del(&mddev->kobj); del_gendisk(mddev->gendisk); } diff --git a/drivers/md/md.h b/drivers/md/md.h index c989cc9f6216b..0a1a227f106b0 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -353,6 +353,7 @@ enum mddev_flags { MD_HAS_MULTIPLE_PPLS, MD_NOT_READY, MD_BROKEN, + MD_DO_DELETE, MD_DELETED, }; -- 2.51.0