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jail: add a missing lock around an osd_jail_call().

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allprison_lock should be at least held shared when jail OSD methods
are called.  Add a shared lock around one such call where that wasn't
the case.

In another such call, change an exclusive lock grab to be shared in
what is likely the more common case.
This commit is contained in:
Jamie Gritton 2020-12-26 20:49:30 -08:00
parent 0fe74ae624
commit 7f4e724829
1 changed files with 9 additions and 3 deletions
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12
sys/kern/kern_jail.c
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@ -2498,8 +2498,9 @@ do_jail_attach(struct thread *td, struct prison *pr)
VOP_UNLOCK(pr->pr_root);
e_revert_osd:
/* Tell modules this thread is still in its old jail after all. */
sx_slock(&allprison_lock);
(void)osd_jail_call(td->td_ucred->cr_prison, PR_METHOD_ATTACH, td);
prison_deref(pr, PD_DEREF | PD_DEUREF);
prison_deref(pr, PD_DEREF | PD_DEUREF | PD_LIST_SLOCKED);
return (error);
}
@ -2687,8 +2688,13 @@ prison_deref(struct prison *pr, int flags)
*/
if (lasturef) {
if (!(flags & (PD_LIST_SLOCKED | PD_LIST_XLOCKED))) {
sx_xlock(&allprison_lock);
flags |= PD_LIST_XLOCKED;
if (ref > 1) {
sx_slock(&allprison_lock);
flags |= PD_LIST_SLOCKED;
} else {
sx_xlock(&allprison_lock);
flags |= PD_LIST_XLOCKED;
}
}
(void)osd_jail_call(pr, PR_METHOD_REMOVE, NULL);
mtx_lock(&pr->pr_mtx);