- Don't hold the proc lock across VREF and the fd* functions to avoid lock
order reversals. - Add some preliminary locking in the !RF_PROC case. - Protect p_estcpu with sched_lock.
This commit is contained in:
parent
e238d2a8da
commit
5641ae5dc3
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=73935
@ -207,6 +207,7 @@ fork1(p1, flags, procp)
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int ok;
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static int pidchecked = 0;
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struct forklist *ep;
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struct filedesc *fd;
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/* Can't copy and clear */
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if ((flags & (RFFDG|RFCFDG)) == (RFFDG|RFCFDG))
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@ -226,8 +227,10 @@ fork1(p1, flags, procp)
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if (flags & RFCFDG) {
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struct filedesc *fdtmp;
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fdtmp = fdinit(p1);
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PROC_LOCK(p1);
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fdfree(p1);
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p1->p_fd = fdtmp;
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PROC_UNLOCK(p1);
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}
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/*
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@ -237,8 +240,10 @@ fork1(p1, flags, procp)
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if (p1->p_fd->fd_refcnt > 1) {
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struct filedesc *newfd;
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newfd = fdcopy(p1);
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PROC_LOCK(p1);
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fdfree(p1);
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p1->p_fd = newfd;
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PROC_UNLOCK(p1);
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}
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}
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*procp = NULL;
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@ -456,15 +461,19 @@ fork1(p1, flags, procp)
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/* bump references to the text vnode (for procfs) */
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p2->p_textvp = p1->p_textvp;
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PROC_UNLOCK(p1);
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PROC_UNLOCK(p2);
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if (p2->p_textvp)
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VREF(p2->p_textvp);
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if (flags & RFCFDG)
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p2->p_fd = fdinit(p1);
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fd = fdinit(p1);
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else if (flags & RFFDG)
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p2->p_fd = fdcopy(p1);
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fd = fdcopy(p1);
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else
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p2->p_fd = fdshare(p1);
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fd = fdshare(p1);
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PROC_LOCK(p2);
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p2->p_fd = fd;
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/*
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* If p_limit is still copy-on-write, bump refcnt,
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@ -472,6 +481,7 @@ fork1(p1, flags, procp)
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* (If PL_SHAREMOD is clear, the structure is shared
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* copy-on-write.)
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*/
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PROC_LOCK(p1);
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if (p1->p_limit->p_lflags & PL_SHAREMOD)
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p2->p_limit = limcopy(p1->p_limit);
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else {
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@ -526,15 +536,22 @@ fork1(p1, flags, procp)
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*/
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if (p1->p_traceflag & KTRFAC_INHERIT) {
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p2->p_traceflag = p1->p_traceflag;
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if ((p2->p_tracep = p1->p_tracep) != NULL)
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if ((p2->p_tracep = p1->p_tracep) != NULL) {
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PROC_UNLOCK(p1);
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PROC_UNLOCK(p2);
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VREF(p2->p_tracep);
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PROC_LOCK(p2);
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PROC_LOCK(p1);
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}
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}
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#endif
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/*
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* set priority of child to be that of parent
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*/
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mtx_lock_spin(&sched_lock);
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p2->p_estcpu = p1->p_estcpu;
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mtx_unlock_spin(&sched_lock);
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/*
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* This begins the section where we must prevent the parent
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