Re: Failures in x86 pmap

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

On Sun, Feb 23, 2020 at 06:59:50PM +0000, Andrew Doran wrote:
> I think I found the problem, which has existed since ~8PM GMT yesterday.
> Hopefully fixed by revision 1.17 of src/sys/arch/x86/x86/x86_tlb.c.

With src from Mon Feb 24 13:18:07 GMT 2020 (so with v 1.17 of
x86_tlb.c), I now see:

(gdb) x/s panicstr
0xffffffff819535c0 <scratchstr.13561>:      "kernel diagnostic assertion \"uvm_page_owner_locked_p(pg, true)\" failed: file \"/usr/src/sys/arch/x86/x86/pmap.c\", line 4041 "

whenever logging into xdm with an nfs mounted /home.

Booting with a kernel from last Monday gets me back to a working amd64 system.
(Not sure if related, but see the magic characters "pmap.c")

Cheers,

Patrick

(gdb) bt
#0  0xffffffff80224225 in cpu_reboot (howto=howto@entry=260, 
    bootstr=bootstr@entry=0x0) at /usr/src/sys/arch/amd64/amd64/machdep.c:720
#1  0xffffffff809c888f in kern_reboot (howto=howto@entry=260, 
    bootstr=bootstr@entry=0x0) at /usr/src/sys/kern/kern_reboot.c:73
#2  0xffffffff80a0ac79 in vpanic (
    fmt=0xffffffff8135b650 "kernel %sassertion \"%s\" failed: file \"%s\", line %d ", ap=ap@entry=0xffffaa814dffcad8) at /usr/src/sys/kern/subr_prf.c:336
#3  0xffffffff80e51f13 in kern_assert (
    fmt=fmt@entry=0xffffffff8135b650 "kernel %sassertion \"%s\" failed: file \"%s\", line %d ") at /usr/src/sys/lib/libkern/kern_assert.c:51
#4  0xffffffff80251869 in pmap_clear_attrs (pg=0xffffaa80002dac50, 
    clearbits=clearbits@entry=4) at /usr/src/sys/arch/x86/x86/pmap.c:4046
#5  0xffffffff808fd094 in pmap_page_protect (prot=1, pg=<optimized out>)
    at ./x86/pmap.h:464
#6  nfs_gop_write (vp=0xffffd6274866adc0, pgs=0xffffaa814dffcc48, npages=1, 
    flags=19) at /usr/src/sys/nfs/nfs_node.c:278
#7  0xffffffff80a80c02 in genfs_do_putpages (vp=0xffffd6274866adc0, 
    startoff=0, endoff=9223372036854771712, origflags=19, busypg=0x0)
    at /usr/src/sys/miscfs/genfs/genfs_io.c:1303
#8  0xffffffff80a7cf40 in VOP_PUTPAGES (vp=vp@entry=0xffffd6274866adc0, 
    offlo=offlo@entry=0, offhi=offhi@entry=0, flags=flags@entry=19)
    at /usr/src/sys/kern/vnode_if.c:1632
#9  0xffffffff8092da43 in nfs_flush (vp=0xffffd6274866adc0, 
    cred=<optimized out>, waitfor=waitfor@entry=1, l=<optimized out>, 
    commit=commit@entry=0) at /usr/src/sys/nfs/nfs_vnops.c:3166
#10 0xffffffff8092dadc in nfs_close (v=<optimized out>) at ./machine/cpu.h:72
#11 0xffffffff80a7b4c0 in VOP_CLOSE (vp=vp@entry=0xffffd6274866adc0, 
    fflag=fflag@entry=2, cred=cred@entry=0xffffd62746737dc0)
    at /usr/src/sys/kern/vnode_if.c:332
#12 0xffffffff80a72d99 in vn_close (vp=0xffffd6274866adc0, flags=2, 
    cred=0xffffd62746737dc0) at /usr/src/sys/kern/vfs_vnops.c:396
#13 0xffffffff809a23dd in closef (fp=fp@entry=0xffffd6274539db40)
    at /usr/src/sys/kern/kern_descrip.c:832
#14 0xffffffff809a26f0 in fd_close (fd=fd@entry=3)
    at /usr/src/sys/kern/kern_descrip.c:715
#15 0xffffffff80a17adb in sys_close (l=0xffffd62733a7c600, 
    uap=<optimized out>, retval=<optimized out>)
    at /usr/src/sys/kern/sys_descrip.c:513
#16 0xffffffff80255cb9 in sy_call (rval=0xffffaa814dffcfb0, 
    uap=0xffffaa814dffd000, l=0xffffd62733a7c600, 
    sy=0xffffffff8185b870 <sysent+144>) at /usr/src/sys/sys/syscallvar.h:65
#17 sy_invoke (code=6, rval=0xffffaa814dffcfb0, uap=0xffffaa814dffd000, 
    l=0xffffd62733a7c600, sy=0xffffffff8185b870 <sysent+144>)
    at /usr/src/sys/sys/syscallvar.h:94
#18 syscall (frame=0xffffaa814dffd000)
    at /usr/src/sys/arch/x86/x86/syscall.c:138
#19 0xffffffff802096ad in handle_syscall ()