Re: kern/55980: panic: kernel diagnostic assertion "atomic_load_relaxed...

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

The following reply was made to PR kern/55980; it has been noted by GNATS.

From: Patrick Welche <prlw1%cam.ac.uk@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/55980: panic:  kernel diagnostic assertion
 "atomic_load_relaxed...
Date: Wed, 2 Jun 2021 17:32:36 +0100

 Managed to reproduce this a couple of times since, with coredumps,
 e.g., 31 May source, 9.99.82/amd64.
 
 First, the full message is:
 
 System panicked: kernel diagnostic assertion "atomic_load_relaxed(&pp->pp_pte.pte_va) == 0" failed: file "../../../../arch/x86/x86/pmap.c", line 4573 
 
 
 #3  0xffffffff80ec68f3 in kern_assert (
     fmt=fmt@entry=0xffffffff8134d970 "kernel %sassertion \"%s\" failed: file \"%s\", line %d ") at ../../../../../../lib/libkern/kern_assert.c:51
 #4  0xffffffff8055f6e7 in pmap_clear_attrs (pg=pg@entry=0xffff9580002bde80, 
     clearbits=clearbits@entry=1) at ../../../../arch/x86/x86/pmap.c:4573
 #5  0xffffffff80cb1a7b in uvm_pagemarkdirty (pg=pg@entry=0xffff9580002bde80, 
     newstatus=newstatus@entry=0) at ../../../../uvm/uvm_page_status.c:124
 #6  0xffffffff80c96beb in uao_get (uobj=0xffff93e9a7973100, 
     offset=<optimized out>, pps=0xffff958b756c87b0, npagesp=<optimized out>, 
     centeridx=<optimized out>, access_type=<optimized out>, advice=0, 
     flags=7170) at ../../../../uvm/uvm_aobj.c:1041
 #7  0xffffffff80c997e2 in ubc_fault (ufi=0xffff958b756c88d0, 
     ign1=<optimized out>, ign2=<optimized out>, ign3=<optimized out>, 
     ign4=<optimized out>, access_type=<optimized out>, flags=<optimized out>)
     at ../../../../uvm/uvm_bio.c:386
 #8  0xffffffff80c9c598 in uvm_fault_internal (
     orig_map=orig_map@entry=0xffffffff81904f40 <kernel_map_store>, 
     vaddr=vaddr@entry=18446627024758292480, access_type=access_type@entry=2, 
     fault_flag=fault_flag@entry=0) at ../../../../uvm/uvm_fault.c:917
 #9  0xffffffff802288c0 in trap (frame=0xffff958b756c8b70)
     at ../../../../arch/amd64/amd64/trap.c:520
 #10 0xffffffff802210e3 in alltraps ()
 #11 0xffff958b6ad6c000 in ?? ()
 #12 0x0000704428b68000 in ?? ()
 #13 0x0000704428b6803b in ?? ()
 #14 0xffff93ec64ea8228 in ?? ()
 #15 0x00007f7ffffff000 in ?? ()
 #16 0xffff958b756c8d00 in ?? ()
 #17 0xffff940072af25c0 in ?? ()
 #18 0xffffffff80dc1ea5 in genfs_islocked (v=<optimized out>)
     at ../../../../miscfs/genfs/genfs_vnops.c:394
 #19 0xffffffff80c99f87 in ubc_uiomove (uobj=uobj@entry=0xffff93e9a7973100, 
     uio=uio@entry=0xffff958b756c8ef0, todo=59, advice=1970048736, 
     advice@entry=0, flags=0, flags@entry=2) at ../../../../uvm/uvm_bio.c:779
 #20 0xffffffff80bdcc27 in tmpfs_write (v=<optimized out>)
     at ../../../../fs/tmpfs/tmpfs_vnops.c:642
 #21 0xffffffff80db7b03 in VOP_WRITE (vp=vp@entry=0xffff93f6895212c0, 
     uio=uio@entry=0xffff958b756c8ef0, ioflag=ioflag@entry=16, 
     cred=cred@entry=0xffff940071889dc0) at ../../../../kern/vnode_if.c:540
 #22 0xffffffff80daf3b7 in vn_write (fp=<optimized out>, 
     offset=0xffff93ec7aacfac0, uio=0xffff958b756c8ef0, 
     cred=0xffff940071889dc0, flags=1) at ../../../../kern/vfs_vnops.c:612
 #23 0xffffffff80d50a4b in dofilewrite (fd=fd@entry=4, fp=0xffff93ec7aacfac0, 
     buf=0x704428b68000, nbyte=59, offset=<optimized out>, flags=flags@entry=1, retval=retval@entry=0xffff958b756c8fb0) at ../../../../kern/sys_generic.c:350
 #24 0xffffffff80d50b60 in sys_write (l=<optimized out>, uap=0xffff958b756c9000, retval=0xffff958b756c8fb0) at ../../../../kern/sys_generic.c:318
 #25 0xffffffff80565ece in sy_call (rval=0xffff958b756c8fb0, uap=0xffff958b756c9000, l=0xffff940070bf32c0, sy=0xffffffff81882b00 <sysent+96>) at ../../../../sys/syscallvar.h:65
 #26 sy_invoke (code=4, rval=0xffff958b756c8fb0, uap=0xffff958b756c9000, l=0xffff940070bf32c0, sy=0xffffffff81882b00 <sysent+96>) at ../../../../sys/syscallvar.h:94
 #27 syscall (frame=0xffff958b756c9000) at ../../../../arch/x86/x86/syscall.c:138
 (gdb) frame 4
 (gdb) print *pp
 $1 = {pp_u = {rb = {rbt_root = 0x0, rbt_ops = 0xffff958b6101c000, 
       rbt_minmax = {0x0, 0x0}}, link = {le_next = 0x0, 
       le_prev = 0xffff958b6101c000}, s = {pte = {pte_ptp = 0x0, 
         pte_va = 18446627024593338368}, pvlist = {lh_first = 0x0}, 
       attrs = 0 '\000'}}, pp_lock = {u = {mtxa_owner = 1537, s = {
         mtxs_dummy = 1 '\001', mtxs_ipl = {_ipl = 6 '\006'}, 
         mtxs_lock = 0 '\000', mtxs_unused = 0 '\000'}}}}
 (gdb) print *pg
 $2 = {pageq = {queue = {tqe_next = 0x1, tqe_prev = 0x1}, list = {
       le_next = 0x1, le_prev = 0x1}}, pqflags = 0, flags = 1606, 
   phys_addr = 74025328640, loan_count = 0, wire_count = 0, uanon = 0x0, 
   uobject = 0xffff93e9a7973100, offset = 0, interlock = {u = {mtxa_owner = 0, 
       s = {mtxs_dummy = 0 '\000', mtxs_ipl = {_ipl = 0 '\000'}, 
         mtxs_lock = 0 '\000', mtxs_unused = 0 '\000'}}}, pdqueue = {
     tqe_next = 0x0, tqe_prev = 0x0}, mdpage = {mp_pp = {pp_u = {rb = {
           rbt_root = 0x0, rbt_ops = 0xffff958b6101c000, rbt_minmax = {0x0, 
             0x0}}, link = {le_next = 0x0, le_prev = 0xffff958b6101c000}, s = {
           pte = {pte_ptp = 0x0, pte_va = 18446627024593338368}, pvlist = {
             lh_first = 0x0}, attrs = 0 '\000'}}, pp_lock = {u = {
           mtxa_owner = 1537, s = {mtxs_dummy = 1 '\001', mtxs_ipl = {
               _ipl = 6 '\006'}, mtxs_lock = 0 '\000', 
             mtxs_unused = 0 '\000'}}}}}}
 (gdb) print pg->flags
 $3 = 1606   == 0x646  = TABLED AOBJ FAKE BUSY DIRTY