From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guoqing Jiang Subject: Re: BUG: unable to handle kernel NULL pointer dereference at sysfs_do_create_link_sd (after mdadm) Date: Wed, 15 Apr 2015 10:44:39 +0800 Message-ID: <552DD097.9010504@suse.com> References: <20150414171537.GH25394@azat> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150414171537.GH25394@azat> Sender: linux-raid-owner@vger.kernel.org To: Azat Khuzhin Cc: "Kernel.org-Linux-RAID" , neilb@suse.de List-Id: linux-raid.ids Azat Khuzhin wrote: > $ git describe > v4.0-2620-gb79013b > > During setting up partitions with mdadm, mdadm hung, after attaching to mdadm with strace I got next: > > # pgrep mdadm | xargs strace -fp > Process 27389 attached - interrupt to quit > unlink("/dev/.tmp.md.27389:9:127") = 0 > mknod("/tmp/.tmp.md.27389:9:127", S_IFBLK|0600, makedev(9, 127)) = 0 > open("/tmp/.tmp.md.27389:9:127", O_RDWR|O_EXCL|O_DIRECT) <-- *hung* > > After, I looked into dmesg, and found this: > [ 9627.630018] ------------[ cut here ]------------ > [ 9627.630029] WARNING: CPU: 18 PID: 3330 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x5a/0x70() > [ 9627.630032] sysfs: cannot create duplicate filename '/devices/virtual/bdi/9:127' > sysfs complains about duplicate filename, maybe you tried to create the array with same node. > [ 9627.630033] Modules linked in: xt_tcpudp iptable_filter ip_tables x_tables nfsd nfs lockd grace sunrpc ipmi_devintf netconsole configfs loop hid_generic usbhid hid x86_pkg_temp_thermal coretemp ghash_clmulni_intel aesni_intel ioatdma ehci_pci aes_x86_64 iTCO_wdt iTCO_ve > [ 9627.630074] CPU: 18 PID: 3330 Comm: mdadm Not tainted 4.0.0bl-azat-v6+ #1 > [ 9627.630076] Hardware name: Supermicro X9DRD-7LN4F(-JBOD)/X9DRD-EF/X9DRD-7LN4F, BIOS 3.0a 12/05/2013 > [ 9627.630077] 0000000000000000 ffffffff814e3fcc ffffffff813e590f ffff885f9bcd3808 > [ 9627.630079] ffffffff8104575c ffff885f96acb000 ffff885fa4b3e3c0 ffff885fa2fec780 > [ 9627.630081] ffff885fa4bc4000 0000000000000000 ffffffff810457d5 ffffffff814e5d78 > [ 9627.630083] Call Trace: > [ 9627.630091] [] ? dump_stack+0x40/0x50 > [ 9627.630096] [] ? warn_slowpath_common+0x7c/0xb0 > [ 9627.630098] [] ? warn_slowpath_fmt+0x45/0x50 > [ 9627.630100] [] ? kernfs_path+0x42/0x50 > [ 9627.630102] [] ? sysfs_warn_dup+0x5a/0x70 > [ 9627.630104] [] ? sysfs_create_dir_ns+0x7e/0x90 > [ 9627.630108] [] ? kobject_add_internal+0x9b/0x2f0 > [ 9627.630109] [] ? kobject_add+0x66/0xb0 > [ 9627.630114] [] ? device_add+0x263/0x620 > [ 9627.630116] [] ? device_create_groups_vargs+0xe8/0x100 > [ 9627.630118] [] ? device_create_vargs+0x13/0x20 > [ 9627.630124] [] ? bdi_register+0x68/0x150 > [ 9627.630129] [] ? add_disk+0x14d/0x4a0 > [ 9627.630132] [] ? alloc_disk_node+0xaf/0x100 > [ 9627.630137] [] ? md_alloc+0x1e9/0x350 [md_mod] > [ 9627.630141] [] ? md_probe+0xb/0x20 [md_mod] > [ 9627.630143] [] ? kobj_lookup+0x104/0x170 > [ 9627.630147] [] ? md_alloc+0x350/0x350 [md_mod] > [ 9627.630149] [] ? get_gendisk+0x28/0xf0 > [ 9627.630153] [] ? __blkdev_get+0x114/0x3c0 > [ 9627.630156] [] ? bdev_direct_access+0xa0/0xa0 > [ 9627.630158] [] ? bdev_test+0x10/0x10 > [ 9627.630160] [] ? blkdev_get+0x38/0x310 > [ 9627.630162] [] ? blkdev_get_by_dev+0x40/0x40 > [ 9627.630167] [] ? do_dentry_open.isra.16+0x153/0x320 > [ 9627.630170] [] ? do_last.isra.51+0x323/0xd50 > [ 9627.630172] [] ? kmem_cache_alloc+0x123/0x130 > [ 9627.630174] [] ? path_openat+0x7f/0x610 > [ 9627.630177] [] ? tlb_flush_mmu_free+0x30/0x50 > [ 9627.630180] [] ? unmap_region+0xb0/0xf0 > [ 9627.630182] [] ? do_filp_open+0x2b/0x90 > [ 9627.630187] [] ? __alloc_fd+0x7c/0x120 > [ 9627.630189] [] ? do_sys_open+0x121/0x210 > [ 9627.630193] [] ? system_call_fastpath+0x12/0x6a > [ 9627.630195] ---[ end trace b7a3e9c6f05c2666 ]--- > [ 9627.630196] ------------[ cut here ]------------ > [ 9627.630198] WARNING: CPU: 18 PID: 3330 at lib/kobject.c:240 kobject_add_internal+0x274/0x2f0() > [ 9627.630200] kobject_add_internal failed for 9:127 with -EEXIST, don't try to register things with the same name in the same directory. > Ditto, seems the same issue. Thanks, Guoqing