7a0c819d28
Dave Jones reports that offlining a CPU leads to this trace: numa_remove_cpu cpu 1 node 0: mask now 0,2-3 smpboot: CPU 1 is now offline BUG: using smp_processor_id() in preemptible [00000000] code: cpu-offline.sh/10591 caller is cmci_rediscover+0x6a/0xe0 Pid: 10591, comm: cpu-offline.sh Not tainted 3.9.0-rc3+ #2 Call Trace: [<ffffffff81333bbd>] debug_smp_processor_id+0xdd/0x100 [<ffffffff8101edba>] cmci_rediscover+0x6a/0xe0 [<ffffffff815f5b9f>] mce_cpu_callback+0x19d/0x1ae [<ffffffff8160ea66>] notifier_call_chain+0x66/0x150 [<ffffffff8107ad7e>] __raw_notifier_call_chain+0xe/0x10 [<ffffffff8104c2e3>] cpu_notify+0x23/0x50 [<ffffffff8104c31e>] cpu_notify_nofail+0xe/0x20 [<ffffffff815ef082>] _cpu_down+0x302/0x350 [<ffffffff815ef106>] cpu_down+0x36/0x50 [<ffffffff815f1c9d>] store_online+0x8d/0xd0 [<ffffffff813edc48>] dev_attr_store+0x18/0x30 [<ffffffff81226eeb>] sysfs_write_file+0xdb/0x150 [<ffffffff811adfb2>] vfs_write+0xa2/0x170 [<ffffffff811ae16c>] sys_write+0x4c/0xa0 [<ffffffff81613019>] system_call_fastpath+0x16/0x1b However, a look at cmci_rediscover shows that it can be simplified quite a bit, apart from solving the above issue. It invokes functions that take spin locks with interrupts disabled, and hence it can run in atomic context. Also, it is run in the CPU_POST_DEAD phase, so the dying CPU is already dead and out of the cpu_online_mask. So take these points into account and simplify the code, and thereby also fix the above issue. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Tony Luck <tony.luck@intel.com> |
||
|---|---|---|
| .. | ||
| boot | ||
| configs | ||
| crypto | ||
| ia32 | ||
| include | ||
| kernel | ||
| kvm | ||
| lguest | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
| oprofile | ||
| pci | ||
| platform | ||
| power | ||
| realmode | ||
| syscalls | ||
| tools | ||
| um | ||
| vdso | ||
| video | ||
| xen | ||
| .gitignore | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.cpu | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile_32.cpu | ||
| Makefile.um | ||