From: Cong Wang <xiyou.wangcong@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Prarit Bhargava <prarit@redhat.com>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <greg@kroah.com>
Subject: Re: [Patch] lkdtm: avoid calling lkdtm_do_action() with spin lock held
Date: Tue, 31 Jan 2012 21:25:19 +0800 [thread overview]
Message-ID: <4F27EBBF.6040103@gmail.com> (raw)
In-Reply-To: <20120130125429.56f6f7d0.akpm@linux-foundation.org>
[-- Attachment #1: Type: text/plain, Size: 310 bytes --]
On 01/31/2012 04:54 AM, Andrew Morton wrote:
>
> lkdtm_handler() can be called from module IRQ handlers, so perhaps the
> same problems can still happen. The patch does improve things though ;)
>
Yeah, what do you think about patch below (untested)?
---
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
[-- Attachment #2: lkdtm-2.diff --]
[-- Type: text/x-patch, Size: 1030 bytes --]
diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c
index 28adefe..5cbd740 100644
--- a/drivers/misc/lkdtm.c
+++ b/drivers/misc/lkdtm.c
@@ -315,7 +315,7 @@ static void lkdtm_do_action(enum ctype which)
}
case CT_OVERWRITE_ALLOCATION: {
size_t len = 1020;
- u32 *data = kmalloc(len, GFP_KERNEL);
+ u32 *data = kmalloc(len, GFP_ATOMIC);
data[1024 / sizeof(u32)] = 0x12345678;
kfree(data);
@@ -323,14 +323,16 @@ static void lkdtm_do_action(enum ctype which)
}
case CT_WRITE_AFTER_FREE: {
size_t len = 1024;
- u32 *data = kmalloc(len, GFP_KERNEL);
+ u32 *data = kmalloc(len, GFP_ATOMIC);
kfree(data);
- schedule();
+ udelay(100);
memset(data, 0x78, len);
break;
}
case CT_SOFTLOCKUP:
+ if (in_interrupt())
+ break;
preempt_disable();
for (;;)
cpu_relax();
@@ -341,6 +343,8 @@ static void lkdtm_do_action(enum ctype which)
cpu_relax();
break;
case CT_HUNG_TASK:
+ if (in_interrupt())
+ break;
set_current_state(TASK_UNINTERRUPTIBLE);
schedule();
break;
next prev parent reply other threads:[~2012-01-31 13:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-28 12:52 [Patch] lkdtm: avoid calling lkdtm_do_action() with spin lock held Cong Wang
2012-01-29 1:15 ` Dave Young
2012-01-30 20:54 ` Andrew Morton
2012-01-31 13:25 ` Cong Wang [this message]
2012-01-31 15:35 ` Arnd Bergmann
2012-02-01 3:01 ` Cong Wang
2012-02-01 15:29 ` Arnd Bergmann
2012-02-02 13:31 ` Cong Wang
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