Date: Fri, 20 Sep 2013 23:16:15 +0000 (UTC) From: Davide Italiano <davide@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r255747 - head/sys/kern Message-ID: <201309202316.r8KNGFeZ007194@svn.freebsd.org>
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Author: davide Date: Fri Sep 20 23:16:15 2013 New Revision: 255747 URL: http://svnweb.freebsd.org/changeset/base/255747 Log: Fix callout_init_rm() in the shared case, allocating storage for 'struct rm_priotracker' directly in the softclock thread. Now consumers can pass CALLOUT_SHAREDLOCK flag to callout initialization routine safely. The choice of the already existing flags instead of special casing shared rmlocks is done to prevent consumer footshooting. Suggested by: jhb Reviewed by: jhb Approved by: re (delphij) Modified: head/sys/kern/kern_timeout.c Modified: head/sys/kern/kern_timeout.c ============================================================================== --- head/sys/kern/kern_timeout.c Fri Sep 20 23:10:52 2013 (r255746) +++ head/sys/kern/kern_timeout.c Fri Sep 20 23:16:15 2013 (r255747) @@ -597,11 +597,13 @@ softclock_call_cc(struct callout *c, str #endif int direct) { + struct rm_priotracker tracker; void (*c_func)(void *); void *c_arg; struct lock_class *class; struct lock_object *c_lock; - int c_flags, sharedlock; + uintptr_t lock_status; + int c_flags; #ifdef SMP struct callout_cpu *new_cc; void (*new_func)(void *); @@ -620,7 +622,13 @@ softclock_call_cc(struct callout *c, str (CALLOUT_PENDING | CALLOUT_ACTIVE), ("softclock_call_cc: pend|act %p %x", c, c->c_flags)); class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; - sharedlock = (c->c_flags & CALLOUT_SHAREDLOCK) ? 0 : 1; + lock_status = 0; + if (c->c_flags & CALLOUT_SHAREDLOCK) { + if (class == &lock_class_rm) + lock_status = (uintptr_t)&tracker; + else + lock_status = 1; + } c_lock = c->c_lock; c_func = c->c_func; c_arg = c->c_arg; @@ -633,7 +641,7 @@ softclock_call_cc(struct callout *c, str cc->cc_exec_entity[direct].cc_cancel = false; CC_UNLOCK(cc); if (c_lock != NULL) { - class->lc_lock(c_lock, sharedlock); + class->lc_lock(c_lock, lock_status); /* * The callout may have been cancelled * while we switched locks.
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