On Tue, 2010-06-08 at 15:59 +0800, Am?rico Wang wrote: > 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. We get 1 here because, crash_get_memory_size() adds 1 as below, size = crashk_res.end - crashk_res.start + 1; We cant remove this addition, as it is required to display correct size in case if we reserve the crash memory. Coming back to issue.. Attaching the patch again. Signed-off-by: Pavan Naregundi <pavan at linux.vnet.ibm.com> Reviewed-by: WANG Cong <xiyou.wangcong at gmail.com> --- -------------- next part -------------- A non-text attachment was scrubbed... Name: fix-crash_shrink_memory.patch Type: text/x-patch Size: 371 bytes Desc: not available URL: <http://lists.infradead.org/pipermail/kexec/attachments/20100608/886bb1c2/attachment.bin>
