FreeBSD lock order reversal (LOR) #279

lock order reversal:
 1st 0xc041d264 XCONS LOCK (XCONS LOCK) @ sys/dev/xen/console/console.c:290
 2nd 0xc2946004 ttymtx (ttymtx) @ sys/dev/xen/console/console.c:274
		
KDB: stack backtrace:
X_db_sym_numargs(c024df5a,c27f1bb4,c00f1115,4,c0249670,...) at X_db_sym_numargs+0x146
kdb_backtrace(4,c0249670,c28921e0,c2894f60,c27f1c10,...) at kdb_backtrace+0x29
witness_display_spinlock(c0250bd0,c2946004,c0253348,c2894f60,c02675ea,...) at witness_display_spinlock+0x75
witness_checkorder(c2946004,9,c02675ea,112,0,...) at witness_checkorder+0x839
_mtx_lock_flags(c2946004,0,c02675ea,112,0,...) at _mtx_lock_flags+0xc4
xencons_rx(c0522000,1,c0267654,56,c024c985,...) at xencons_rx+0x4a
xencons_handle_input(0,c27f1cc8,c00a3a94,c02aef40,c28cfd38,...) at xencons_handle_input+0x5d
intr_event_execute_handlers(c28d17ec,c28cfd00,c02470f5,4dd,c28cfd70,...) at intr_event_execute_handlers+0x125
intr_event_add_handler(c28d06e0,c27f1d38,c0246e64,32d,c28d17ec,...) at intr_event_add_handler+0x42f
fork_exit(c0092ee0,c28d06e0,c27f1d38) at fork_exit+0xb8
fork_trampoline() at fork_trampoline+0x8
--- trap 0, eip = 0, esp = 0xc27f1d70, ebp = 0 ---
		

• freebsd-current (thread)