d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix callout_init_rm() in the shared case, allocating storage for 'struct

Browse Source 
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)
This commit is contained in:
Davide Italiano 2013-09-20 23:16:15 +00:00
parent cabba8f230
commit 1f96759fb1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=255747
1 changed files with 11 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
sys/kern/kern_timeout.c
View File

@ -597,11 +597,13 @@ softclock_call_cc(struct callout *c, struct callout_cpu *cc,
#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, struct callout_cpu *cc,
(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, struct callout_cpu *cc,
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.