On Sun, 29 Jun 2025, Konstantin Belousov wrote:
On Sat, Jun 28, 2025 at 11:23:01PM +0000, Bjoern A. Zeeb wrote:
On Sun, 29 Jun 2025, Konstantin Belousov wrote:
On Sat, Jun 28, 2025 at 05:32:17PM +0000, Bjoern A. Zeeb wrote:
Hi,
happened in one of my dev VMs:
# more /etc/wpa_supplicant.conf Illegal instruction (core dumped)
As I see nothing in UPDATING in the range from HEAD to the commit I
rebased --onto b93161a7e38d (downgrade of the kernel) that would
explain this I am wondering.
Mounted the disk image from the base system and checked the core:
Program terminated with signal SIGILL, Illegal instruction.
(gdb) where
#0 0x00003fabd04ebeed in tgetflag_sp (sp=0x3fa3ad42f3a0 <get_term[termbuf]>, id=0x3fa3ad42f3a0
<get_term[termbuf]> "") at /usr/src/contrib/ncurses/ncurses/tinfo/lib_termcap.c:259
#1 0x00003fa3ad404e9e in get_term () at /usr/src/contrib/less/screen.c:1256
#2 0x00003fa3ad4042ef in main (argc=1, argv=0x3fabce1f26b8) at
/usr/src/contrib/less/main.c:344
What is the instruction that faulted?
Also show the registers values used by the instruction.
I am a bit rusty with this user spaec stuff ;-) Hope the below helps.
(gdb) display/i $pc
1: x/i $pc
=> 0x3fabd04ebeed <tgetflag_sp+29>: cmove %rbx,%rcx
So this is kind of impossible.
I wonder what's going on; that's #3 of really funky things I am seeing
lately on different machines/VM/arhcitectures/source trees.
The instruction CMOVE is there from the PentiumPro times. It does not
access any resources except registers. It cannot cause the vmexit on its
own since it cannot generate exceptions (well perhaps except code fetch
page fault). The only possible vmexit on this instruction is due to
external events. But then bhyve does not generate #UD.
BTW was it intel or amd cpu?
intel
Could it be due to any corruption?
I'll keep a copy of the disk image for now but I need to keep moving and
would love to do a complete installworld/kernel again just to see.
BTW, when I tried gdb inside the VM it dumped core as well; same thing:
(gdb) display/i $pc
1: x/i $pc
=> 0x828064eed <tgetflag_sp+29>: cmove %rbx,%rcx
(gdb) info f
Stack level 0, frame at 0x821dde8f0:
rip = 0x828064eed in tgetflag_sp
(/usr/src/contrib/ncurses/ncurses/tinfo/lib_termcap.c:259); saved rip =
0x8238b10ef
called by frame at 0x821dde950
source language c.
Arglist at 0x821dde8e0, args: sp=0xb2fd3634000, id=0xb2fd3634000 ""
Locals at 0x821dde8e0, Previous frame's sp is 0x821dde8f0
Saved registers:
rbx at 0x821dde8d0, rbp at 0x821dde8e0, r14 at 0x821dde8d8, rip at 0x821dde8e8
(gdb) info r
rax 0x828077c30 35031317552
rbx 0x0 0
rcx 0xffffffffffffd720 -10464
rdx 0x821ddf05f 34927931487
rsi 0xb2fd3634000 12300037865472
rdi 0xb2fd3634000 12300037865472
rbp 0x821dde8e0 0x821dde8e0
rsp 0x821dde8e0 0x821dde8e0
r8 0xfffffffc 4294967292
r9 0x3 3
r10 0x54 84
r11 0x206 518
r12 0x1ff63a0 33514400
r13 0x8238c9488 34956153992
r14 0x821ddf05f 34927931487
r15 0x0 0
rip 0x828064eed 0x828064eed <tgetflag_sp+29>
eflags 0x10246 [ PF ZF IF RF ]
cs 0x43 67
ss 0x3b 59
ds 0x3b 59
es 0x3b 59
fs 0x13 19
gs 0x1b 27
fs_base 0xb2fd329d970 12300034103664
gs_base 0x0 0
(gdb) where
#0 0x0000000828064eed in tgetflag_sp (sp=0xb2fd3634000, id=0xb2fd3634000 "")
at /usr/src/contrib/ncurses/ncurses/tinfo/lib_termcap.c:259
#1 0x00000008238b10ef in _rl_init_terminal_io () from
/usr/local/lib/libreadline.so.8
#2 0x00000008238b19d3 in rl_reset_terminal () from
/usr/local/lib/libreadline.so.8
#3 0x0000000001822313 in init_page_info() ()
#4 0x00000000017eb74d in gdb_init() ()
#5 0x000000000159d7c3 in ?? ()
#6 0x000000000159c7bc in gdb_main(captured_main_args*) ()
#7 0x00000000012a87c1 in main ()
--
Bjoern A. Zeeb r15:7
