> Date: Thu, 17 Dec 2020 18:56:52 -0300 > From: Martin Pieuchot <m...@openbsd.org> > > On 16/12/20(Wed) 22:49, Greg Steuck wrote: > > I just hit this while booting an i386-current in vmd. The source tree is > > synced to "Remove the assertion in uvm_km_pgremove()." > > > > I enabled WITNESS on top of GENERIC. Naturally, GENERIC-Dec15 snap works. > > > > Anybody else see this so I know it's worth a bisect? > > [...] > > I can reproduce it. Diff below fixes it. This is the beginning of a > rabbit hole... thanks! > > > witness: lock_object uninitialized: 0xd0f3c828 > > Starting stack trace... > > witness_checkorder(0,d6bb011c,d1155e6c,d02e10e4,90) at > > witness_checkorder+0x8a > > witness_checkorder(d0f3c828,9,0) at witness_checkorder+0x8a > > mtx_enter(d0f3c81c) at mtx_enter+0x27 > > pmap_extract_pae(d8bb0d80,f5605000,d8bb0da0) at pmap_extract_pae+0x53 > > pmap_pinit_pd_pae(d8bb0d80) at pmap_pinit_pd_pae+0x268 > > pmap_create(1,1000,f6fe5e86,d8bbfd54,d0f5ba18) at pmap_create+0xa8 > > uvmspace_fork(d0f5b5fc,d8bb3e34,d0f5b5fc,1,d1155f70) at uvmspace_fork+0x56 > > process_new(d8bb3e34,d0f5b5fc,1) at process_new+0xeb > > fork1(d0eb7b14,1,d04eb560,0,0,d1155f90) at fork1+0x1ba > > panic: acquiring blockable sleep lock with spinlock or critical section > > held (rwlock) kmmaplk > > pmap_kernel()'s mutexes aren't initialized. Diff below does that.
Well, that is somewhat intentional. Those mutexes should never be used for the kernel pmap. The kernel pmap is always there and is updated atomically. So how did we end up trying to grab one of these mutexs? > Index: arch/i386/i386/pmap.c > =================================================================== > RCS file: /cvs/src/sys/arch/i386/i386/pmap.c,v > retrieving revision 1.209 > diff -u -p -r1.209 pmap.c > --- arch/i386/i386/pmap.c 24 Sep 2020 11:36:50 -0000 1.209 > +++ arch/i386/i386/pmap.c 17 Dec 2020 21:47:11 -0000 > @@ -961,6 +961,8 @@ pmap_bootstrap(vaddr_t kva_start) > */ > > kpm = pmap_kernel(); > + mtx_init(&kpm->pm_mtx, IPL_VM); > + mtx_init(&kpm->pm_apte_mtx, IPL_VM); > uvm_objinit(&kpm->pm_obj, NULL, 1); > bzero(&kpm->pm_list, sizeof(kpm->pm_list)); /* pm_list not used */ > kpm->pm_pdir = (vaddr_t)(proc0.p_addr->u_pcb.pcb_cr3 + KERNBASE); > >
