Date: Tue, 30 Mar 2004 18:24:20 -0500 From: John Baldwin <jhb@FreeBSD.org> To: alpha@FreeBSD.org Cc: freebsd-current@freebsd.org Subject: Re: -current panic Message-ID: <200403301824.20780.jhb@FreeBSD.org> In-Reply-To: <20040329212151.GA10421@electra.cse.Buffalo.EDU> References: <20040329212151.GA10421@electra.cse.Buffalo.EDU>
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On Monday 29 March 2004 04:21 pm, Ken Smith wrote:
> Is this one a known issue on alpha or is it something new? While
> someone was using gdb on beast (alpha cluster ref machine) to trace
> a program beast crashes with this:
>
> panic: mutex process lock not owned at ../../../kern/kern_mutex.c:277
> at line 719 in file ../../../kern/kern_mutex.c
> cpuid = 1;
> Stack backtrace:
> db_print_backtrace() at db_print_backtrace+0x18
> backtrace() at backtrace+0x2c
> __panic() at __panic+0x210
> _mtx_assert() at _mtx_assert+0xec
> _mtx_unlock_flags() at _mtx_unlock_flags+0xa4
> ptrace_single_step() at ptrace_single_step+0x6c
> kern_ptrace() at kern_ptrace+0x3c4
> ptrace() at ptrace+0xe8
> syscall() at syscall+0x37c
> XentSys() at XentSys+0x64
> --- syscall (26) ---
> --- user mode ---
> boot() called on cpu#1
>
> It seems to be reproducible...
This is what I tried to get tested earlier. :) Try this patch below:
Index: machdep.c
===================================================================
RCS file: /usr/cvs/src/sys/alpha/alpha/machdep.c,v
retrieving revision 1.218
diff -u -r1.218 machdep.c
--- machdep.c 1 Mar 2004 19:19:15 -0000 1.218
+++ machdep.c 30 Mar 2004 23:22:34 -0000
@@ -1914,10 +1914,9 @@
if (td->td_md.md_flags & (MDTD_STEP1|MDTD_STEP2))
panic("ptrace_single_step: step breakpoints not removed");
- PROC_UNLOCK(td->td_proc);
error = ptrace_read_int(td, pc, &ins.bits);
if (error)
- goto err;
+ return (error);
switch (ins.branch_format.opcode) {
@@ -1957,20 +1956,18 @@
td->td_md.md_sstep[0].addr = addr[0];
error = ptrace_set_bpt(td, &td->td_md.md_sstep[0]);
if (error)
- goto err;
+ return (error);
if (count == 2) {
td->td_md.md_sstep[1].addr = addr[1];
error = ptrace_set_bpt(td, &td->td_md.md_sstep[1]);
if (error) {
ptrace_clear_bpt(td, &td->td_md.md_sstep[0]);
- goto err;
+ return (error);
}
td->td_md.md_flags |= MDTD_STEP2;
} else
td->td_md.md_flags |= MDTD_STEP1;
-err:
- PROC_LOCK(td->td_proc);
return (error);
}
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org
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