On Tue, Jun 08, 2010 at 12:37:37PM +0530, Pavan Naregundi wrote: >Adding CC's.. > > >On Mon, 2010-06-07 at 12:58 +0530, Pavan Naregundi wrote: >> Hi Everyone, >> >> Please add me to CC in your reply.. >> >> When crashkernel is not enabled, "echo 0 > /sys/kernel/kexec_crash_size" >> will generate OOPS message in the kernel. Below is the OOPS message and >> other details, >> >> # cat /proc/cmdline >> ro LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us console=hvc0 >> rhgb root=UUID=eafd9874-010c-46f9-a0c6-ea8db7c61ac3 >> # uname -a >> Linux XXXXXXXX 2.6.35-rc1 #1 SMP Mon Jun 7 18:04:53 IST 2010 ppc64 ppc64 >> ppc64 GNU/Linux >> # cd /sys/kernel/ >> # ls >> debug kexec_loaded profiling uevent_seqnum >> kexec_crash_loaded mm security vmcoreinfo >> kexec_crash_size notes uevent_helper >> # cat kexec_crash_loaded >> 0 >> # cat kexec_loaded >> 0 >> # cat kexec_crash_size >> 1 >> # echo 0 > kexec_crash_size >> Unable to handle kernel paging request for data at address 0x00000030 >> Faulting instruction address: 0xc0000000000930b4 >> Oops: Kernel access of bad area, sig: 11 [#1] >> SMP NR_CPUS=1024 NUMA pSeries >> last sysfs file: /sys/kernel/kexec_crash_size >> Modules linked in: sunrpc ipv6 ext3 jbd dm_mirror dm_region_hash dm_log >> dm_multipath dm_mod uinput sg ehea sr_mod ibmveth cdrom ext4 jbd2 >> mbcache sd_mod crc_t10dif ibmvscsic scsi_transport_srp scsi_tgt [last >> unloaded: scsi_wait_scan] >> NIP: c0000000000930b4 LR: c0000000000930ac CTR: c0000000000b7ce0 >> REGS: c0000000b7803750 TRAP: 0300 Not tainted (2.6.35-rc1) >> MSR: 8000000000009032 <EE,ME,IR,DR> CR: 28242482 XER: 20000000 >> DAR: 0000000000000030, DSISR: 0000000040000000 >> TASK = c0000000b9cc3dc0[1381] 'bash' THREAD: c0000000b7800000 CPU: 12 >> GPR00: c0000000000930ac c0000000b78039d0 c000000000e885a8 >> c000000000f42950 >> GPR04: c0000000b7803af0 0000000000000008 0000000000000002 >> c0000000005c6438 >> GPR08: 0000000000000000 000000008000000c 0000000000000000 >> 0000000000000000 >> GPR12: 0000000040242448 c000000007441e00 00000000100f6210 >> 0000000000000000 >> GPR16: 00000000100f4a38 00000000100cfb98 00000000100f4bdc >> 00000000100f4b4c >> GPR20: 00000000103f4de8 0000000000000000 0000000000000000 >> 00000000100f0000 >> GPR24: c0000000005c65c0 0000000000000000 c000000000da83e0 >> c0000000bc67f780 >> GPR28: c0000000bc684ae0 c000000000f42950 c000000000e1e3f8 >> c000000000da8408 >> NIP [c0000000000930b4] .release_resource+0x34/0xe0 >> LR [c0000000000930ac] .release_resource+0x2c/0xe0 >> Call Trace: >> [c0000000b78039d0] [c0000000000930ac] .release_resource+0x2c/0xe0 >> (unreliable) >> [c0000000b7803a60] [c0000000000d4fc8] .crash_shrink_memory+0x1c8/0x1f0 >> [c0000000b7803b30] [c0000000000b7d38] .kexec_crash_size_store+0x58/0x90 >> [c0000000b7803bc0] [c0000000002b0bb4] .kobj_attr_store+0x34/0x50 >> [c0000000b7803c30] [c000000000226d5c] .sysfs_write_file+0xec/0x1f0 >> [c0000000b7803ce0] [c00000000019e0bc] .vfs_write+0xec/0x1f0 >> [c0000000b7803d80] [c00000000019e2e8] .SyS_write+0x58/0xb0 >> [c0000000b7803e30] [c00000000000852c] syscall_exit+0x0/0x40 >> Instruction dump: >> fba1ffe8 fbc1fff0 fbe1fff8 ebc2b228 7c7f1b78 f8010010 f821ff71 ebbe8000 >> 7fa3eb78 484e35d9 60000000 e97f0020 <e92b0030> 2fa90000 419e002c >> 7fbf4800 >> ---[ end trace afbc780462c9bf4e ]--- >> >> When crashkernel is not enabled, crashk_res resource have not been >> reserved. Hence crashk_res.parent will be NULL. >> >> Attaching a simple patch to this problem. Patch is tested and resolves this bug. Ouch... The patch indeed addresses the problem, looks good to me. Please add your Signed-off-by and my: Reviewed-by: WANG Cong <xiyou.wangcong at gmail.com> Another problem is that you should get 0 instead of 1 when you don't reserve any memory. Thanks!
