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Finish fixing up Alpha to work with an MP safe ptrace():

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- ptrace_single_step() is no longer called with the proc lock held, so
  don't try to unlock it and then relock it.
- Push Giant down into proc_rwmem() instead of forcing all the consumers
  (including Alpha breakpoint support) to explicitly wrap calls to
  proc_rwmem() with Giant.

Tested by:	kensmith
This commit is contained in:
John Baldwin 2004-04-01 20:56:44 +00:00
parent 72673aaaa2
commit e43257aa7d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=127730
2 changed files with 11 additions and 14 deletions
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9
sys/alpha/alpha/machdep.c
View file

@ -1914,10 +1914,9 @@ ptrace_single_step(struct thread *td)
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 @@ ptrace_single_step(struct thread *td)
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);
}

16
sys/kern/sys_process.c
View file

@ -154,18 +154,21 @@ proc_rwmem(struct proc *p, struct uio *uio)
vm_prot_t reqprot;
int error, writing;
GIANT_REQUIRED;
mtx_lock(&Giant);
/*
* if the vmspace is in the midst of being deallocated or the
* process is exiting, don't try to grab anything. The page table
* usage in that process can be messed up.
*/
vm = p->p_vmspace;
if ((p->p_flag & P_WEXIT))
if ((p->p_flag & P_WEXIT)) {
mtx_unlock(&Giant);
return (EFAULT);
if (vm->vm_refcnt < 1)
}
if (vm->vm_refcnt < 1) {
mtx_unlock(&Giant);
return (EFAULT);
}
++vm->vm_refcnt;
/*
* The map we want...
@ -274,6 +277,7 @@ proc_rwmem(struct proc *p, struct uio *uio)
} while (error == 0 && uio->uio_resid > 0);
vmspace_free(vm);
mtx_unlock(&Giant);
return (error);
}
@ -602,9 +606,7 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
uio.uio_segflg = UIO_SYSSPACE; /* i.e.: the uap */
uio.uio_rw = write ? UIO_WRITE : UIO_READ;
uio.uio_td = td;
mtx_lock(&Giant);
error = proc_rwmem(p, &uio);
mtx_unlock(&Giant);
if (uio.uio_resid != 0) {
/*
* XXX proc_rwmem() doesn't currently return ENOSPC,
@ -645,9 +647,7 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
default:
return (EINVAL);
}
mtx_lock(&Giant);
error = proc_rwmem(p, &uio);
mtx_unlock(&Giant);
piod->piod_len -= uio.uio_resid;
return (error);