Fix a race where an attempt to unlock a lock in the completion AST routine
could crash on SMP.
Signed-off-by: Patrick Caulfield <[email protected]>
Signed-off-by: David Teigland <[email protected]>
Index: linux/drivers/dlm/device.c
===================================================================
--- linux.orig/drivers/dlm/device.c
+++ linux/drivers/dlm/device.c
@@ -53,6 +53,7 @@ static rwlock_t lockinfo_lock;
#define LI_FLAG_COMPLETE 1
#define LI_FLAG_FIRSTLOCK 2
#define LI_FLAG_PERSISTENT 3
+#define LI_FLAG_ONLIST 4
/* flags in ls_flags*/
#define LS_FLAG_DELETED 1
@@ -382,6 +383,7 @@ static void ast_routine(void *param)
spin_lock(&li->li_file->fi_li_lock);
list_del(&li->li_ownerqueue);
+ clear_bit(LI_FLAG_ONLIST, &li->li_flags);
spin_unlock(&li->li_file->fi_li_lock);
release_lockinfo(li);
return;
@@ -889,6 +891,7 @@ static int do_user_lock(struct file_info
spin_lock(&fi->fi_li_lock);
list_add(&li->li_ownerqueue, &fi->fi_li_list);
+ set_bit(LI_FLAG_ONLIST, &li->li_flags);
spin_unlock(&fi->fi_li_lock);
if (add_lockinfo(li))
printk(KERN_WARNING "Add lockinfo failed\n");
@@ -920,6 +923,7 @@ static int do_user_unlock(struct file_in
return -ENOMEM;
spin_lock(&fi->fi_li_lock);
list_add(&li->li_ownerqueue, &fi->fi_li_list);
+ set_bit(LI_FLAG_ONLIST, &li->li_flags);
spin_unlock(&fi->fi_li_lock);
}
@@ -934,6 +938,12 @@ static int do_user_unlock(struct file_in
if (kparams->flags & DLM_LKF_CANCEL && li->li_grmode != -1)
convert_cancel = 1;
+ /* Wait until dlm_lock() has completed */
+ if (!test_bit(LI_FLAG_ONLIST, &li->li_flags)) {
+ down(&li->li_firstlock);
+ up(&li->li_firstlock);
+ }
+
/* dlm_unlock() passes a 0 for castaddr which means don't overwrite
the existing li_castaddr as that's the completion routine for
unlocks. dlm_unlock_wait() specifies a new AST routine to be
@@ -949,6 +959,7 @@ static int do_user_unlock(struct file_in
if (!status && !convert_cancel) {
spin_lock(&fi->fi_li_lock);
list_del(&li->li_ownerqueue);
+ clear_bit(LI_FLAG_ONLIST, &li->li_flags);
spin_unlock(&fi->fi_li_lock);
}
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
