I think maybe no one had tested kexec-tools after cpu hot-remove. So the bug remains until today. For both two patches: Reviewed-by: Zhang Yanfei <zhangyanfei at cn.fujitsu.com> On 06/05/2014 01:10 PM, Takao Indoh wrote: > After cpu hot-removing, kexec command fails with the following message. > > "/sys/devices" does not exist. Sysfs does not seem to be mounted. Try > mounting sysfs. > > Of course sysfs is mounted. kexec tried to open > /sys/devices/system/cpu/cpu30/crash_notes but it failed because > /sys/devices/system/cpu/cpu30 did not exist. > > > [Before hot-remove] > > # ls /sys/devices/system/cpu/ > cpu0 cpu111 cpu18 cpu31 cpu45 cpu59 cpu72 cpu86 cpuidle > cpu1 cpu112 cpu19 cpu32 cpu46 cpu6 cpu73 cpu87 intel_pstate > cpu10 cpu113 cpu2 cpu33 cpu47 cpu60 cpu74 cpu88 kernel_max > cpu100 cpu114 cpu20 cpu34 cpu48 cpu61 cpu75 cpu89 microcode > cpu101 cpu115 cpu21 cpu35 cpu49 cpu62 cpu76 cpu9 modalias > cpu102 cpu116 cpu22 cpu36 cpu5 cpu63 cpu77 cpu90 offline > cpu103 cpu117 cpu23 cpu37 cpu50 cpu64 cpu78 cpu91 online > cpu104 cpu118 cpu24 cpu38 cpu51 cpu65 cpu79 cpu92 possible > cpu105 cpu119 cpu25 cpu39 cpu52 cpu66 cpu8 cpu93 power > cpu106 cpu12 cpu26 cpu4 cpu53 cpu67 cpu80 cpu94 present > cpu107 cpu13 cpu27 cpu40 cpu54 cpu68 cpu81 cpu95 probe > cpu108 cpu14 cpu28 cpu41 cpu55 cpu69 cpu82 cpu96 release > cpu109 cpu15 cpu29 cpu42 cpu56 cpu7 cpu83 cpu97 uevent > cpu11 cpu16 cpu3 cpu43 cpu57 cpu70 cpu84 cpu98 > cpu110 cpu17 cpu30 cpu44 cpu58 cpu71 cpu85 cpu99 > > > [After hot-remove] > > # ls /sys/devices/system/cpu/ > cpu0 cpu16 cpu23 cpu4 cpu65 cpu72 cpu8 cpu87 modalias uevent > cpu1 cpu17 cpu24 cpu5 cpu66 cpu73 cpu80 cpu88 offline > cpu10 cpu18 cpu25 cpu6 cpu67 cpu74 cpu81 cpu89 online > cpu11 cpu19 cpu26 cpu60 cpu68 cpu75 cpu82 cpu9 possible > cpu12 cpu2 cpu27 cpu61 cpu69 cpu76 cpu83 cpuidle power > cpu13 cpu20 cpu28 cpu62 cpu7 cpu77 cpu84 intel_pstate present > cpu14 cpu21 cpu29 cpu63 cpu70 cpu78 cpu85 kernel_max probe > cpu15 cpu22 cpu3 cpu64 cpu71 cpu79 cpu86 microcode release > > You can see cpu30 to cpu59, and cpu90 to cpu119 does not exist, they are > removed from this system by hot-remove operation. > > kexec command expects the number of each directory is contiguous. For > example, if sysconf(_SC_NPROCESSORS_CONF) is 60, kexec thinks directory > cpu0, cpu1, cpu2, .... cpu59 exists. But in this case, the number of > directory is not contiguous. That is the root cause of this problem. > This patches fix it. > > Takao Indoh (2): > Enumerate all /sys/devices/system/cpu/cpuN when they are discontiguous > Fix mistaken check of stat(2) return value > > kexec/crashdump-elf.c | 5 ++++- > kexec/crashdump.c | 2 +- > 2 files changed, 5 insertions(+), 2 deletions(-) > -- Thanks. Zhang Yanfei
