OK, I've run tests now. The system did not crash or otherwise misbehave, but the dmesg output was quite verbose, and included "error -19" messages. Here's a sample (apparently for just one CPU core; this sequence was repeated quite a few times):

[  439.341956] smpboot: Booting Node 1 Processor 31 APIC 0x1f
[  439.354783] EDAC sbridge: Seeking for: PCI ID 8086:2fa0
[  439.354795] EDAC sbridge: Seeking for: PCI ID 8086:2fa0
[  439.354814] EDAC sbridge: Seeking for: PCI ID 8086:2fa0
[  439.354836] EDAC sbridge: Seeking for: PCI ID 8086:2f60
[  439.354849] EDAC sbridge: Seeking for: PCI ID 8086:2fa8
[  439.354853] EDAC sbridge: Seeking for: PCI ID 8086:2fa8
[  439.354859] EDAC sbridge: Seeking for: PCI ID 8086:2fa8
[  439.354866] EDAC sbridge: Seeking for: PCI ID 8086:2f71
[  439.354870] EDAC sbridge: Seeking for: PCI ID 8086:2f71
[  439.354876] EDAC sbridge: Seeking for: PCI ID 8086:2f71
[  439.354882] EDAC sbridge: Seeking for: PCI ID 8086:2faa
[  439.354886] EDAC sbridge: Seeking for: PCI ID 8086:2faa
[  439.354892] EDAC sbridge: Seeking for: PCI ID 8086:2faa
[  439.354898] EDAC sbridge: Seeking for: PCI ID 8086:2fab
[  439.354902] EDAC sbridge: Seeking for: PCI ID 8086:2fab
[  439.354909] EDAC sbridge: Seeking for: PCI ID 8086:2fab
[  439.354915] EDAC sbridge: Seeking for: PCI ID 8086:2fac
[  439.354919] EDAC sbridge: Seeking for: PCI ID 8086:2fac
[  439.354925] EDAC sbridge: Seeking for: PCI ID 8086:2fac
[  439.354931] EDAC sbridge: Seeking for: PCI ID 8086:2fad
[  439.354936] EDAC sbridge: Seeking for: PCI ID 8086:2fad
[  439.354942] EDAC sbridge: Seeking for: PCI ID 8086:2fad
[  439.354948] EDAC sbridge: Seeking for: PCI ID 8086:2f68
[  439.354953] EDAC sbridge: Seeking for: PCI ID 8086:2f68
[  439.354960] EDAC sbridge: Seeking for: PCI ID 8086:2f68
[  439.354965] EDAC sbridge: Seeking for: PCI ID 8086:2f79
[  439.354978] EDAC sbridge: Seeking for: PCI ID 8086:2f6a
[  439.354991] EDAC sbridge: Seeking for: PCI ID 8086:2f6b
[  439.355003] EDAC sbridge: Seeking for: PCI ID 8086:2f6c
[  439.355016] EDAC sbridge: Seeking for: PCI ID 8086:2f6d
[  439.355029] EDAC sbridge: Seeking for: PCI ID 8086:2ffc
[  439.355033] EDAC sbridge: Seeking for: PCI ID 8086:2ffc
[  439.355039] EDAC sbridge: Seeking for: PCI ID 8086:2ffc
[  439.355046] EDAC sbridge: Seeking for: PCI ID 8086:2ffd
[  439.355049] EDAC sbridge: Seeking for: PCI ID 8086:2ffd
[  439.355055] EDAC sbridge: Seeking for: PCI ID 8086:2ffd
[  439.355062] EDAC sbridge: Seeking for: PCI ID 8086:2fbd
[  439.355067] EDAC sbridge: Seeking for: PCI ID 8086:2fbd
[  439.355073] EDAC sbridge: Seeking for: PCI ID 8086:2fbd
[  439.355079] EDAC sbridge: Seeking for: PCI ID 8086:2fbf
[  439.355084] EDAC sbridge: Seeking for: PCI ID 8086:2fbf
[  439.355090] EDAC sbridge: Seeking for: PCI ID 8086:2fbf
[  439.355095] EDAC sbridge: Seeking for: PCI ID 8086:2fb9
[  439.355101] EDAC sbridge: Seeking for: PCI ID 8086:2fb9
[  439.355107] EDAC sbridge: Seeking for: PCI ID 8086:2fb9
[  439.355112] EDAC sbridge: Seeking for: PCI ID 8086:2fbb
[  439.355117] EDAC sbridge: Seeking for: PCI ID 8086:2fbb
[  439.355123] EDAC sbridge: Seeking for: PCI ID 8086:2fbb
[  439.355355] EDAC MC0: Giving out device to module sb_edac.c controller Haswell SrcID#1_Ha#0: DEV 0000:ff:12.0 (INTERRUPT)
[  439.355601] EDAC MC1: Giving out device to module sb_edac.c controller Haswell SrcID#0_Ha#0: DEV 0000:7f:12.0 (INTERRUPT)
[  439.355629] EDAC sbridge: Some needed devices are missing
[  439.382001] EDAC MC: Removed device 0 for sb_edac.c Haswell SrcID#1_Ha#0: DEV 0000:ff:12.0
[  439.398059] EDAC MC: Removed device 1 for sb_edac.c Haswell SrcID#0_Ha#0: DEV 0000:7f:12.0
[  439.398115] EDAC sbridge: Couldn't find mci handler
[  439.399135] EDAC sbridge: Couldn't find mci handler
[  439.399887] EDAC sbridge: Failed to register device with error -19.