From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 056FCC4332F for ; Tue, 16 Nov 2021 19:05:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5BD463214 for ; Tue, 16 Nov 2021 19:05:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239826AbhKPTII (ORCPT ); Tue, 16 Nov 2021 14:08:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:51526 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239827AbhKPTIA (ORCPT ); Tue, 16 Nov 2021 14:08:00 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 11FAA61391; Tue, 16 Nov 2021 19:05:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637089503; bh=cnE1MXGiLmPpRtN/cnvdTU1sq0u1ItfQ4UaqvApuf0A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EoKJg5qTljSmo5+Ij2dNJSi2vKNBg56PVK7r2+nCjoLIi6l0zaqY1db/66gmq5zu8 phRatpkd0jEib/XM2CQY0NO+J4i0EQNrhAg5BlfN0H7h7785rN0FtYNnqsK86L3k+N w6HRl/jVV11Co7RELGoDNN/oFIEA+bBHMQ51/ufBgfa5tGBrF9eCjVWOjXna4ZSTsb fCVUVdO1ktQkfs6EarHsasxtzmCGcRgZDniWhYSGJpuM8zWWGw5P6h6qIQzb26ypnW YPq+4S30IV/mZPF/ZxSK185cVFZFLCXT5yuIyLyBjjtn5wQxV6JLsp/zfRLibrL0TR 0L8vLUheFSWLA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zheyu Ma , Sam Ravnborg , Sasha Levin , daniel.vetter@ffwll.ch, willy@infradead.org, penguin-kernel@i-love.sakura.ne.jp, geert+renesas@glider.be, xiyuyang19@fudan.edu.cn, linux@roeck-us.net, thunder.leizhen@huawei.com, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 07/65] fbdev: fbmem: Fix double free of 'fb_info->pixmap.addr' Date: Tue, 16 Nov 2021 14:03:27 -0500 Message-Id: <20211116190443.2418144-7-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211116190443.2418144-1-sashal@kernel.org> References: <20211116190443.2418144-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org From: Zheyu Ma [ Upstream commit 2c0c19b681d5a331b53aab0d170f72a87c7bff12 ] savagefb and some other drivers call kfree to free 'info->pixmap.addr' even after calling unregister_framebuffer, which may cause double free. Fix this by setting 'fb_info->pixmap.addr' to NULL after kfree in unregister_framebuffer. The following log reveals it: [ 37.318872] BUG: KASAN: double-free or invalid-free in kfree+0x13e/0x290 [ 37.319369] [ 37.320803] Call Trace: [ 37.320992] dump_stack_lvl+0xa8/0xd1 [ 37.321274] print_address_description+0x87/0x3b0 [ 37.321632] ? kfree+0x13e/0x290 [ 37.321879] ? kfree+0x13e/0x290 [ 37.322126] ? kfree+0x13e/0x290 [ 37.322374] kasan_report_invalid_free+0x58/0x90 [ 37.322724] ____kasan_slab_free+0x123/0x140 [ 37.323049] __kasan_slab_free+0x11/0x20 [ 37.323347] slab_free_freelist_hook+0x81/0x150 [ 37.323689] ? savagefb_remove+0xa1/0xc0 [savagefb] [ 37.324066] kfree+0x13e/0x290 [ 37.324304] savagefb_remove+0xa1/0xc0 [savagefb] [ 37.324655] pci_device_remove+0xa9/0x250 [ 37.324959] ? pci_device_probe+0x7d0/0x7d0 [ 37.325273] device_release_driver_internal+0x4f7/0x7a0 [ 37.325666] driver_detach+0x1e8/0x2c0 [ 37.325952] bus_remove_driver+0x134/0x290 [ 37.326262] ? sysfs_remove_groups+0x97/0xb0 [ 37.326584] driver_unregister+0x77/0xa0 [ 37.326883] pci_unregister_driver+0x2c/0x1c0 [ 37.336124] [ 37.336245] Allocated by task 5465: [ 37.336507] ____kasan_kmalloc+0xb5/0xe0 [ 37.336801] __kasan_kmalloc+0x9/0x10 [ 37.337069] kmem_cache_alloc_trace+0x12b/0x220 [ 37.337405] register_framebuffer+0x3f3/0xa00 [ 37.337731] foo_register_framebuffer+0x3b/0x50 [savagefb] [ 37.338136] [ 37.338255] Freed by task 5475: [ 37.338492] kasan_set_track+0x3d/0x70 [ 37.338774] kasan_set_free_info+0x23/0x40 [ 37.339081] ____kasan_slab_free+0x10b/0x140 [ 37.339399] __kasan_slab_free+0x11/0x20 [ 37.339694] slab_free_freelist_hook+0x81/0x150 [ 37.340034] kfree+0x13e/0x290 [ 37.340267] do_unregister_framebuffer+0x21c/0x3d0 [ 37.340624] unregister_framebuffer+0x23/0x40 [ 37.340950] savagefb_remove+0x45/0xc0 [savagefb] [ 37.341302] pci_device_remove+0xa9/0x250 [ 37.341603] device_release_driver_internal+0x4f7/0x7a0 [ 37.341990] driver_detach+0x1e8/0x2c0 [ 37.342272] bus_remove_driver+0x134/0x290 [ 37.342577] driver_unregister+0x77/0xa0 [ 37.342873] pci_unregister_driver+0x2c/0x1c0 [ 37.343196] cleanup_module+0x15/0x1c [savagefb] [ 37.343543] __se_sys_delete_module+0x398/0x490 [ 37.343881] __x64_sys_delete_module+0x56/0x60 [ 37.344221] do_syscall_64+0x4d/0xc0 [ 37.344492] entry_SYSCALL_64_after_hwframe+0x44/0xae Signed-off-by: Zheyu Ma Signed-off-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/1633848148-29747-1-git-send-email-zheyuma97@gmail.com Signed-off-by: Sasha Levin --- drivers/video/fbdev/core/fbmem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 7420d2c16e47e..826175ad88a2f 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1702,8 +1702,11 @@ static void do_unregister_framebuffer(struct fb_info *fb_info) { unlink_framebuffer(fb_info); if (fb_info->pixmap.addr && - (fb_info->pixmap.flags & FB_PIXMAP_DEFAULT)) + (fb_info->pixmap.flags & FB_PIXMAP_DEFAULT)) { kfree(fb_info->pixmap.addr); + fb_info->pixmap.addr = NULL; + } + fb_destroy_modelist(&fb_info->modelist); registered_fb[fb_info->node] = NULL; num_registered_fb--; -- 2.33.0