From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752591AbeC2Jwa (ORCPT ); Thu, 29 Mar 2018 05:52:30 -0400 Received: from lucky1.263xmail.com ([211.157.147.131]:34653 "EHLO lucky1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752525AbeC2Jw2 (ORCPT ); Thu, 29 Mar 2018 05:52:28 -0400 X-263anti-spam: KSV:0; X-MAIL-GRAY: 1 X-MAIL-DELIVERY: 0 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-RL-SENDER: shawn.lin@rock-chips.com X-FST-TO: linux-kernel@vger.kernel.org X-SENDER-IP: 58.22.7.114 X-LOGIN-NAME: shawn.lin@rock-chips.com X-UNIQUE-TAG: X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Cc: ulf.hansson@linaro.org, linus.walleij@linaro.org, adrian.hunter@intel.com, shawn.lin@rock-chips.com, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [mmc_block] Prevent bus reference leak in mmc_blk_init To: Alexander Kappner References: <1522275511-7693-1-git-send-email-agk@godking.net> From: Shawn Lin Message-ID: Date: Thu, 29 Mar 2018 17:52:25 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <1522275511-7693-1-git-send-email-agk@godking.net> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/3/29 6:18, Alexander Kappner wrote: > Upon module load, mmc_block allocates a bus with bus_register in > mmc_blk_init. This reference never gets freed during module unload. > Subsequent re-insertions of the module fail and BUG() is triggered: WARN() is triggered. > > [ 84.583342] sysfs: cannot create duplicate filename '/bus/mmc_rpmb' > [ 84.583373] CPU: 6 PID: 1825 Comm: modprobe Tainted: P O 4.16.0-rc6-00384-gf36b753 #30 > [ 84.583381] Hardware name: LENOVO 20ENCTO1WW/20ENCTO1WW, BIOS N1EET62W (1.35 ) 11/10/2016 > [ 84.583385] Call Trace: > [ 84.583401] dump_stack+0x5a/0x75 > [ 84.583411] sysfs_warn_dup+0x58/0x70 > [ 84.583419] sysfs_create_dir_ns+0x70/0x80 > [ 84.583437] kobject_add_internal+0xa5/0x2c0 > [ 84.583453] kset_register+0x44/0x60 > [ 84.583470] bus_register+0xc6/0x270 > [ 84.583479] ? 0xffffffffa000d000 > [ 84.583492] mmc_blk_init+0x12/0x1000 [mmc_block] > [ 84.583501] do_one_initcall+0x4e/0x194 > [ 84.583510] ? ___cache_free+0x21/0x2b0 > [ 84.583524] do_init_module+0x5a/0x20f > [ 84.583533] load_module+0x235c/0x2510 > [ 84.583550] ? SYSC_finit_module+0x80/0xb0 > [ 84.583558] SYSC_finit_module+0x80/0xb0 > [ 84.583570] do_syscall_64+0x77/0x290 > [ 84.583580] entry_SYSCALL_64_after_hwframe+0x3d/0xa2 > [ 84.583587] RIP: 0033:0x7f452a3ad5b9 > [ 84.583593] RSP: 002b:00007fff4562ba18 EFLAGS: 00000206 ORIG_RAX: 0000000000000139 > [ 84.583602] RAX: ffffffffffffffda RBX: 000056092895c520 RCX: 00007f452a3ad5b9 > [ 84.583607] RDX: 0000000000000000 RSI: 000056092697b3d9 RDI: 0000000000000003 > [ 84.583612] RBP: 000056092697b3d9 R08: 0000000000000000 R09: 000056092895d310 > [ 84.583617] R10: 0000000000000003 R11: 0000000000000206 R12: 0000000000000000 > [ 84.583623] R13: 000056092895c430 R14: 0000000000040000 R15: 0000000000040000 > [ 84.583647] ------------[ cut here ]------------ > [ 84.583656] kobject_add_internal failed for mmc_rpmb with -EEXIST, don't try to register things with the same name in the same directory. > [ 84.583694] WARNING: CPU: 6 PID: 1825 at lib/kobject.c:238 kobject_add_internal+0x296/0x2c0 > [ 84.583705] Modules linked in: mmc_block(+) rtsx_pci_sdmmc rtsx_pci iwlmvm mac80211 nvidia_drm(PO) nvidia_modeset(PO) iwlwifi nvidia(PO) cfg80211 qmi_wwan thinkpad_acpi rfkill sdhci_pci cqhci sdhci mfd_core [last unloaded: mmc_block] > [ 84.583770] CPU: 6 PID: 1825 Comm: modprobe Tainted: P O 4.16.0-rc6-00384-gf36b753 #30 > [ 84.583774] Hardware name: LENOVO 20ENCTO1WW/20ENCTO1WW, BIOS N1EET62W (1.35 ) 11/10/2016 > [ 84.583782] RIP: 0010:kobject_add_internal+0x296/0x2c0 > [ 84.583786] RSP: 0018:ffffc9000769bc58 EFLAGS: 00010296 > [ 84.583791] RAX: 000000000000007d RBX: ffff880fcf588618 RCX: 0000000000000000 > [ 84.583796] RDX: 0000000000040400 RSI: 00000000000000f6 RDI: 00000000ffffffff > [ 84.583801] RBP: 00000000ffffffef R08: 0000000000000000 R09: 0000000000000354 > [ 84.583806] R10: ffffffff8251fc74 R11: 0000000000000353 R12: ffff88100d3cf698 > [ 84.583811] R13: ffff880fcf588618 R14: ffffffffa0028590 R15: ffffffffa0028540 > [ 84.583818] FS: 00007f452a853700(0000) GS:ffff881053d80000(0000) knlGS:0000000000000000 > [ 84.583823] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 84.583837] CR2: 00007f452a3faea0 CR3: 0000000fc89e4004 CR4: 00000000003606e0 > [ 84.583850] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 84.583863] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 84.583875] Call Trace: > [ 84.583893] kset_register+0x44/0x60 > [ 84.583902] bus_register+0xc6/0x270 > [ 84.583910] ? 0xffffffffa000d000 > [ 84.583926] mmc_blk_init+0x12/0x1000 [mmc_block] > [ 84.583940] do_one_initcall+0x4e/0x194 > [ 84.583948] ? ___cache_free+0x21/0x2b0 > [ 84.583966] do_init_module+0x5a/0x20f > [ 84.583979] load_module+0x235c/0x2510 > [ 84.583995] ? SYSC_finit_module+0x80/0xb0 > [ 84.584001] SYSC_finit_module+0x80/0xb0 > [ 84.584010] do_syscall_64+0x77/0x290 > [ 84.584016] entry_SYSCALL_64_after_hwframe+0x3d/0xa2 > [ 84.584021] RIP: 0033:0x7f452a3ad5b9 > [ 84.584025] RSP: 002b:00007fff4562ba18 EFLAGS: 00000206 ORIG_RAX: 0000000000000139 > [ 84.584030] RAX: ffffffffffffffda RBX: 000056092895c520 RCX: 00007f452a3ad5b9 > [ 84.584034] RDX: 0000000000000000 RSI: 000056092697b3d9 RDI: 0000000000000003 > [ 84.584038] RBP: 000056092697b3d9 R08: 0000000000000000 R09: 000056092895d310 > [ 84.584043] R10: 0000000000000003 R11: 0000000000000206 R12: 0000000000000000 > [ 84.584047] R13: 000056092895c430 R14: 0000000000040000 R15: 0000000000040000 > [ 84.584053] Code: 7b 20 49 89 c4 48 85 ff 0f 84 10 fe ff ff e9 cd fd ff ff 48 8b 13 48 c7 c6 00 80 f4 81 48 c7 c7 e0 ad 0f 82 31 c0 e8 ca 9a 7b ff <0f> 0b e9 5f fe ff ff 0f 0b 0f 0b 0f 0b 0f 0b e9 71 ff ff ff 0f > [ 84.584147] ---[ end trace d27b36e0e2c0e7e5 ]--- > [ 84.584162] mmcblk: could not register RPMB bus type > > Steps to reproduce: > > Build with CONFIG_MMC_BLOCK=m > > modprobe mmc_block > rmmod mmc_block > modprobe mmc_block > > The proposed patch deallocates the reference in mmc_blk_exit. > Fixes: 97548575bef3 ("mmc: block: Convert RPMB to a character device") Cc: Stable > Signed-off-by: Alexander Kappner > --- > drivers/mmc/core/block.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c > index 2cfb963..9c6f639 100644 > --- a/drivers/mmc/core/block.c > +++ b/drivers/mmc/core/block.c > @@ -3087,6 +3087,7 @@ static void __exit mmc_blk_exit(void) > mmc_unregister_driver(&mmc_driver); > unregister_blkdev(MMC_BLOCK_MAJOR, "mmc"); > unregister_chrdev_region(mmc_rpmb_devt, MAX_DEVICES); > + bus_unregister(&mmc_rpmb_bus_type); Reviewed-by: Shawn Lin > } > > module_init(mmc_blk_init); >