diff options
author | Robert Morris <[email protected]> | 2016-09-08 14:22:38 -0400 |
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committer | Robert Morris <[email protected]> | 2016-09-08 14:22:38 -0400 |
commit | d63ac118e817ecab6fd4f890960f4f73b4dfd5e8 (patch) | |
tree | 7f7b5326ee8c8bf026c731e19c53dd72eec67175 /proc.c | |
parent | 5bf3fbee00fb27cb8cb4eca72dcd9fc4c288ed71 (diff) | |
download | xv6-labs-d63ac118e817ecab6fd4f890960f4f73b4dfd5e8.tar.gz xv6-labs-d63ac118e817ecab6fd4f890960f4f73b4dfd5e8.tar.bz2 xv6-labs-d63ac118e817ecab6fd4f890960f4f73b4dfd5e8.zip |
this might fix the reported deadlock, though I can't reproduce it.
Diffstat (limited to 'proc.c')
-rw-r--r-- | proc.c | 18 |
1 files changed, 17 insertions, 1 deletions
@@ -82,6 +82,12 @@ userinit(void) acquire(&ptable.lock); p = allocproc(); + + // release the lock in case namei() sleeps. + // the lock isn't needed because no other + // thread will look at an EMBRYO proc. + release(&ptable.lock); + initproc = p; if((p->pgdir = setupkvm()) == 0) panic("userinit: out of memory?"); @@ -99,6 +105,12 @@ userinit(void) safestrcpy(p->name, "initcode", sizeof(p->name)); p->cwd = namei("/"); + // this assignment to p->state lets other cores + // run this process. the acquire forces the above + // writes to be visible, and the lock is also needed + // because the assignment might not be atomic. + acquire(&ptable.lock); + p->state = RUNNABLE; release(&ptable.lock); @@ -141,6 +153,8 @@ fork(void) return -1; } + release(&ptable.lock); + // Copy process state from p. if((np->pgdir = copyuvm(proc->pgdir, proc->sz)) == 0){ kfree(np->kstack); @@ -165,6 +179,8 @@ fork(void) pid = np->pid; + acquire(&ptable.lock); + np->state = RUNNABLE; release(&ptable.lock); @@ -227,7 +243,7 @@ wait(void) acquire(&ptable.lock); for(;;){ - // Scan through table looking for zombie children. + // Scan through table looking for exited children. havekids = 0; for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){ if(p->parent != proc) |