korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-13 23:34:05 +08:00
Code Issues Packages Projects Releases Wiki Activity

drivers/misc/lkdtm.c: fix race when crashpoint is hit multiple times before checking count

Browse Source 
We observed the crash point count going negative in cases where the
crash point is hit multiple times before the check of "count == 0" is
done.  Because of this we never call lkdtm_do_action().  This patch just
adds a spinlock to protect count.

Reported-by: Tapan Dhimant <tdhimant@akamai.com>
Signed-off-by: Josh Hunt <johunt@akamai.com>
Acked-by: Ankita Garg <ankita@in.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Josh Hunt 2011-06-27 16:18:08 -07:00 committed by Linus Torvalds
parent 507c5f1224
commit aa2c96d6f3
1 changed files with 8 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/misc/lkdtm.c
View File

@ -120,6 +120,7 @@ static int recur_count = REC_NUM_DEFAULT;
static enum cname cpoint = CN_INVALID;
static enum ctype cptype = CT_NONE;
static int count = DEFAULT_COUNT;
static DEFINE_SPINLOCK(count_lock);
module_param(recur_count, int, 0644);
MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test, "\
@ -230,11 +231,14 @@ static const char *cp_name_to_str(enum cname name)
static int lkdtm_parse_commandline(void)
{
int i;
unsigned long flags;
if (cpoint_count < 1 || recur_count < 1)
return -EINVAL;
spin_lock_irqsave(&count_lock, flags);
count = cpoint_count;
spin_unlock_irqrestore(&count_lock, flags);
/* No special parameters */
if (!cpoint_type && !cpoint_name)
@ -349,6 +353,9 @@ static void lkdtm_do_action(enum ctype which)
static void lkdtm_handler(void)
{
unsigned long flags;
spin_lock_irqsave(&count_lock, flags);
count--;
printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
@ -357,6 +364,7 @@ static void lkdtm_handler(void)
lkdtm_do_action(cptype);
count = cpoint_count;
}
spin_unlock_irqrestore(&count_lock, flags);
}
static int lkdtm_register_cpoint(enum cname which)