On Tue, Jan 21, 2020 at 07:59:35PM +0000, Andrew Doran wrote:
Hi Thomas,
On Tue, Jan 21, 2020 at 08:47:44PM +0100, Thomas Klausner wrote:
During a bulk build (in rust AFAICT), I got a panic with
panic: kernel diagnostic assertion "ci->ci_biglock_count == 0" failed: file "/usr/src/sys/sys/userret.h", line 88
That's this one:
static __inline void
mi_userret(struct lwp *l)
{
struct cpu_info *ci;
KPREEMPT_DISABLE(l);
ci = l->l_cpu;
KASSERT(l->l_blcnt == 0);
KASSERT(ci->ci_biglock_count == 0);
The backtrace in the crash dump is not very helpful:
(gdb) bt
#0 0xffffffff80224315 in cpu_reboot (howto=howto@entry=260, bootstr=bootstr@entry=0x0) at /usr/src/sys/arch/amd64/amd64/machdep.c:720
#1 0xffffffff809f5ec3 in kern_reboot (howto=howto@entry=260, bootstr=bootstr@entry=0x0) at /usr/src/sys/kern/kern_reboot.c:61
#2 0xffffffff80a37109 in vpanic (fmt=0xffffffff8135e980 "kernel %sassertion \"%s\" failed: file \"%s\", line %d ", ap=ap@entry=0xffffad0928973f48)
at /usr/src/sys/kern/subr_prf.c:336
#3 0xffffffff80e7b0b3 in kern_assert (fmt=fmt@entry=0xffffffff8135e980 "kernel %sassertion \"%s\" failed: file \"%s\", line %d ")
at /usr/src/sys/lib/libkern/kern_assert.c:51
#4 0xffffffff802568ce in mi_userret (l=0xffffcfc320ca9c00) at /usr/src/sys/sys/userret.h:91
#5 userret (l=0xffffcfc320ca9c00) at ./machine/userret.h:81
#6 syscall (frame=<optimized out>) at /usr/src/sys/arch/x86/x86/syscall.c:166
#7 0xffffffff802096ad in handle_syscall ()
hannken@ supplied me with a repro for this one so I'm going to look into it
tomorrow morning. syzbot has also run into it recently.
This should be fixed now, with the following revisions:
cvs rdiff -u -r1.165 -r1.166 src/sys/kern/kern_lock.c
cvs rdiff -u -r1.336 -r1.337 src/sys/kern/kern_synch.c
Cheers,
Andrew