dlpar_online_cpu() attempts to online all threads of a core that has been added to an LPAR. If onlining a non-primary thread fails (e.g. due to an allocation failure), the core is left with at least one thread online. dlpar_cpu_add() attempts to roll back the whole operation, releasing the core back to the platform. However, since some threads of the core being removed are still online, the BUG_ON(cpu_online(cpu)) in pseries_remove_processor() strikes:
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 3 PID: 8587 Comm: drmgr Not tainted 5.3.0-rc2-00190-g9b123d1ea237-dirty #46 NIP: c0000000000eeb2c LR: c0000000000eeac4 CTR: c0000000000ee9e0 REGS: c0000001f745b6c0 TRAP: 0700 Not tainted (5.3.0-rc2-00190-g9b123d1ea237-dirty) MSR: 800000010282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]> CR: 44002448 XER: 00000000 CFAR: c00000000195d718 IRQMASK: 0 GPR00: c0000000000eeac4 c0000001f745b950 c0000000032f6200 0000000000000008 GPR04: 0000000000000008 c000000003349c78 0000000000000040 00000000000001ff GPR08: 0000000000000008 0000000000000000 0000000000000001 0007ffffffffffff GPR12: 0000000084002844 c00000001ecacb80 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000008 GPR24: c000000003349ee0 c00000000334a2e4 c0000000fca4d7a8 c000000001d20048 GPR28: 0000000000000001 ffffffffffffffff ffffffffffffffff c0000000fca4d7c4 NIP [c0000000000eeb2c] pseries_smp_notifier+0x14c/0x2e0 LR [c0000000000eeac4] pseries_smp_notifier+0xe4/0x2e0 Call Trace: [c0000001f745b950] [c0000000000eeac4] pseries_smp_notifier+0xe4/0x2e0 (unreliable) [c0000001f745ba10] [c0000000001ac774] notifier_call_chain+0xb4/0x190 [c0000001f745bab0] [c0000000001ad62c] blocking_notifier_call_chain+0x7c/0xb0 [c0000001f745baf0] [c00000000167bda0] of_detach_node+0xc0/0x110 [c0000001f745bb50] [c0000000000e7ae4] dlpar_detach_node+0x64/0xa0 [c0000001f745bb80] [c0000000000edefc] dlpar_cpu_add+0x31c/0x360 [c0000001f745bc10] [c0000000000ee980] dlpar_cpu_probe+0x50/0xb0 [c0000001f745bc50] [c00000000002cf70] arch_cpu_probe+0x40/0x70 [c0000001f745bc70] [c000000000ccd808] cpu_probe_store+0x48/0x80 [c0000001f745bcb0] [c000000000cbcef8] dev_attr_store+0x38/0x60 [c0000001f745bcd0] [c00000000059c980] sysfs_kf_write+0x70/0xb0 [c0000001f745bd10] [c00000000059afb8] kernfs_fop_write+0xf8/0x280 [c0000001f745bd60] [c0000000004b437c] __vfs_write+0x3c/0x70 [c0000001f745bd80] [c0000000004b8710] vfs_write+0xd0/0x220 [c0000001f745bdd0] [c0000000004b8acc] ksys_write+0x7c/0x140 [c0000001f745be20] [c00000000000bbd8] system_call+0x5c/0x68 Move dlpar_offline_cpu() before dlpar_online_cpu() so the latter can use the former to re-offline any threads it has onlined when it encounters an error. Signed-off-by: Nathan Lynch <[email protected]> --- arch/powerpc/platforms/pseries/hotplug-cpu.c | 118 ++++++++++--------- 1 file changed, 60 insertions(+), 58 deletions(-) diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index bbda646b63b5..50e1a9b9b1d5 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -338,6 +338,63 @@ static void pseries_remove_processor(struct device_node *np) cpu_maps_update_done(); } +static int dlpar_offline_cpu(struct device_node *dn) +{ + int rc = 0; + unsigned int cpu; + int len, nthreads, i; + const __be32 *intserv; + u32 thread; + + intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len); + if (!intserv) + return -EINVAL; + + nthreads = len / sizeof(u32); + + cpu_maps_update_begin(); + for (i = 0; i < nthreads; i++) { + thread = be32_to_cpu(intserv[i]); + for_each_present_cpu(cpu) { + if (get_hard_smp_processor_id(cpu) != thread) + continue; + + if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE) + break; + + if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) { + set_preferred_offline_state(cpu, + CPU_STATE_OFFLINE); + cpu_maps_update_done(); + timed_topology_update(1); + rc = device_offline(get_cpu_device(cpu)); + if (rc) + goto out; + cpu_maps_update_begin(); + break; + + } + + /* + * The cpu is in CPU_STATE_INACTIVE. + * Upgrade it's state to CPU_STATE_OFFLINE. + */ + set_preferred_offline_state(cpu, CPU_STATE_OFFLINE); + BUG_ON(plpar_hcall_norets(H_PROD, thread) + != H_SUCCESS); + __cpu_die(cpu); + break; + } + if (cpu == num_possible_cpus()) + printk(KERN_WARNING "Could not find cpu to offline with physical id 0x%x\n", thread); + } + cpu_maps_update_done(); + +out: + return rc; + +} + static int dlpar_online_cpu(struct device_node *dn) { int rc = 0; @@ -364,8 +421,10 @@ static int dlpar_online_cpu(struct device_node *dn) timed_topology_update(1); find_and_online_cpu_nid(cpu); rc = device_online(get_cpu_device(cpu)); - if (rc) + if (rc) { + dlpar_offline_cpu(dn); goto out; + } cpu_maps_update_begin(); break; @@ -505,63 +564,6 @@ static ssize_t dlpar_cpu_add(u32 drc_index) return rc; } -static int dlpar_offline_cpu(struct device_node *dn) -{ - int rc = 0; - unsigned int cpu; - int len, nthreads, i; - const __be32 *intserv; - u32 thread; - - intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len); - if (!intserv) - return -EINVAL; - - nthreads = len / sizeof(u32); - - cpu_maps_update_begin(); - for (i = 0; i < nthreads; i++) { - thread = be32_to_cpu(intserv[i]); - for_each_present_cpu(cpu) { - if (get_hard_smp_processor_id(cpu) != thread) - continue; - - if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE) - break; - - if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) { - set_preferred_offline_state(cpu, - CPU_STATE_OFFLINE); - cpu_maps_update_done(); - timed_topology_update(1); - rc = device_offline(get_cpu_device(cpu)); - if (rc) - goto out; - cpu_maps_update_begin(); - break; - - } - - /* - * The cpu is in CPU_STATE_INACTIVE. - * Upgrade it's state to CPU_STATE_OFFLINE. - */ - set_preferred_offline_state(cpu, CPU_STATE_OFFLINE); - BUG_ON(plpar_hcall_norets(H_PROD, thread) - != H_SUCCESS); - __cpu_die(cpu); - break; - } - if (cpu == num_possible_cpus()) - printk(KERN_WARNING "Could not find cpu to offline with physical id 0x%x\n", thread); - } - cpu_maps_update_done(); - -out: - return rc; - -} - static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index) { int rc; -- 2.20.1
