From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id B44306B00A1 for ; Mon, 19 Jan 2009 04:15:48 -0500 (EST) Message-ID: <49744499.2040101@cn.fujitsu.com> Date: Mon, 19 Jan 2009 17:15:05 +0800 From: Li Zefan MIME-Version: 1.0 Subject: [memcg BUG] NULL pointer dereference wheng rmdir Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki , Balbir Singh Cc: Daisuke Nishimura , "linux-mm@kvack.org" List-ID: I tested it on IA64, below are the steps to reproduce the bug: # mount -t cgroup -o memory xxx /mnt # mkdir /mnt/0 # for pid in `cat /mnt/tasks`; do echo $pid > /mnt/0/tasks; done # for pid in `cat /mnt/0/tasks`; do echo $pid > /mnt/tasks; done # rmdir /mnt/0 =========================================================================== Unable to handle kernel NULL pointer dereference (address 0000000000002680) rmdir[11520]: Oops 8821862825984 [1] Modules linked in: autofs4 sunrpc ipmi_watchdog ipmi_devintf ipmi_si ipmi_msghandler vfat fat dm_mirror dm_region_hash dm_log dm_multipath dm_mod rng_core e100 iTCO_wdt mii iTCO_vendor_support button sg usb_storage lpfc scsi_transport_fc shpchp mptspi mptscsih mptbase scsi_transport_spi sd_mod scsi_mod ext3 jbd mbcache uhci_hcd ohci_hcd ehci_hcd [last unloaded: ipmi_watchdog] Pid: 11520, CPU 1, comm: rmdir psr : 00001010085a2010 ifs : 8000000000000001 ip : [] Not tainted (2.6.29-rc2-mm1-FOR_BISECT) ip is at _raw_spin_trylock+0x20/0x80 unat: 0000000000000000 pfs : 0000000000000286 rsc : 0000000000000003 rnat: 0000000000555659 bsps: a000000100190380 pr : 000000000055a699 ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c8a70033f csd : 0000000000000000 ssd : 0000000000000000 b0 : a0000001006035c0 b6 : a000000100016760 b7 : a00000010000bae0 f6 : 1003e6b6b6b6b6b6b6b6b f7 : 0ffe8b01d00cce0000000 f8 : 1003e0000000000003bf0 f9 : 1003efffffffffffffbb8 f10 : 10002dffffffff5b74c91 f11 : 1003e0000000000000000 r1 : a000000100dc48c0 r2 : 0000000000000001 r3 : ffffffffffffffff r8 : 0000000000000010 r9 : 0000000000004000 r10 : 0000000000000001 r11 : 0000000000000000 r12 : e0000040cabbfd90 r13 : e0000040cabb0000 r14 : e0000040cabb0e98 r15 : 0000000000000001 r16 : e000012085df54b8 r17 : e000012085df5468 r18 : e000012085df5468 r19 : 0000000000000000 r20 : 0000000000000000 r21 : 0000000000000000 r22 : 0000000000000000 r23 : e000012085df5468 r24 : e0000000011e2f88 r25 : e000012085b20238 r26 : 0000000000000080 r27 : e0000000011e2f08 r28 : e000012085b201a0 r29 : 0000000000000000 r30 : e0000000011e2f00 r31 : 0000000000000000 Call Trace: [] show_stack+0x40/0xa0 sp=e0000040cabbf960 bsp=e0000040cabb1238 [] show_regs+0x850/0x8a0 sp=e0000040cabbfb30 bsp=e0000040cabb11d8 [] die+0x230/0x360 sp=e0000040cabbfb30 bsp=e0000040cabb1190 [] ia64_do_page_fault+0xa00/0xb60 sp=e0000040cabbfb30 bsp=e0000040cabb1140 [] ia64_native_leave_kernel+0x0/0x280 sp=e0000040cabbfbc0 bsp=e0000040cabb1140 [] _raw_spin_trylock+0x20/0x80 sp=e0000040cabbfd90 bsp=e0000040cabb1138 [] _spin_lock_irqsave+0x60/0x1a0 sp=e0000040cabbfd90 bsp=e0000040cabb1110 [] mem_cgroup_force_empty+0x1f0/0xd60 sp=e0000040cabbfd90 bsp=e0000040cabb1070 [] mem_cgroup_pre_destroy+0x30/0x60 sp=e0000040cabbfda0 bsp=e0000040cabb1048 [] cgroup_rmdir+0x150/0x8e0 sp=e0000040cabbfda0 bsp=e0000040cabb1008 [] vfs_rmdir+0x110/0x1e0 sp=e0000040cabbfda0 bsp=e0000040cabb0fc0 [] do_rmdir+0x170/0x240 sp=e0000040cabbfda0 bsp=e0000040cabb0f88 [] sys_rmdir+0x30/0x60 sp=e0000040cabbfe30 bsp=e0000040cabb0f30 [] ia64_trace_syscall+0xf0/0x130 sp=e0000040cabbfe30 bsp=e0000040cabb0f30 [] __kernel_syscall_via_break+0x0/0x20 sp=e0000040cabc0000 bsp=e0000040cabb0f30 note: rmdir[11520] exited with preempt_count 1 =========================================================================== And I've confirmed it's because (zone == NULL) in mem_cgroup_force_empty_list(): -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org