FreeBSD lock order reversal (LOR) #109

lock order reversal
 1st 0xc0979dc0 UMA lock (UMA lock) @ sys/vm/uma_core.c:1475
 2nd 0xc1061144 system map (system map) @ sys/vm/vm_map.c:2317
		
KDB: stack backtrace:
kdb_backtrace(0,ffffffff,c092eef8,c092f038,c08b9964) at kdb_backtrace+0x29
witness_checkorder(c1061144,9,c0870168,90d) at witness_checkorder+0x564
_mtx_lock_flags(c1061144,0,c0870168,90d) at _mtx_lock_flags+0x5b
_vm_map_lock(c10610c0,c0870168,90d) at _vm_map_lock+0x26
vm_map_remove(c10610c0,c19e0000,c19e1000,c83adc08,c077e2c1) at vm_map_remove+0x1f
kmem_free(c10610c0,c19e0000,1000,c83adc38,c077dc72) at kmem_free+0x25
page_free(c19e0000,1000,2) at page_free+0x29
zone_drain(c104adc0) at zone_drain+0x26a
zone_foreach(c077da08,c83adcec,c078f487,c133c180,c83adc74) at zone_foreach+0x37
uma_reclaim(c133c180,c83adc74,0,c0925520,c83adc80) at uma_reclaim+0x12
vm_pageout_scan(0,c097a220,0,c0871655,5c3) at vm_pageout_scan+0x103
vm_pageout(0,c83add38,0,c0790240,0) at vm_pageout+0x2c3
fork_exit(c0790240,0,c83add38) at fork_exit+0xa0
fork_trampoline() at fork_trampoline+0x8
--- trap 0x1, eip = 0, esp = 0xc83add6c, ebp = 0 ---
		

• freebsd-current (thread)
• see also 007
• patch