From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
To: "Yang, Chenyuan" <cy54@illinois.edu>,
"linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "jani.nikula@intel.com" <jani.nikula@intel.com>,
"syzkaller@googlegroups.com" <syzkaller@googlegroups.com>,
"mchehab@kernel.org" <mchehab@kernel.org>,
"Zhao, Zijie" <zijie4@illinois.edu>,
"Zhang, Lingming" <lingming@illinois.edu>
Subject: Re: [Linux Kernel Bugs] KASAN: slab-use-after-free Read in cec_queue_msg_fh and 4 other crashes in the cec device (`cec_ioctl`)
Date: Tue, 30 Jan 2024 15:35:40 +0100 [thread overview]
Message-ID: <f1855145-9562-4bef-800f-43bcacff6fc8@xs4all.nl> (raw)
In-Reply-To: <526380BE-57AC-493D-A7B0-B8F0ECC0FE0A@illinois.edu>
On 29/01/2024 04:03, Yang, Chenyuan wrote:
> Hi Hans,
>
> Thanks a lot for this new patch!
>
> After applying this new patch in the latest kernel (hash: ecb1b8288dc7ccbdcb3b9df005fa1c0e0c0388a7) and fuzzing with Syzkaller, it seems that the hang still exists.
> To help you better debug it, I attached the covered lines for the fuzz testing and the output of `git diff`. Hope this could help you.
>
> By the way, the syscall descriptions for CEC have been merged into the Syzkaller mainstream: https://github.com/google/syzkaller/blob/master/sys/linux/dev_cec.txt.
>
> Let me know if you need further information.
>
> Best,
> Chenyuan
Here is another patch. This now time outs on all wait_for_completion calls
and reports a WARN_ON and shows additional info. Hopefully this will give me
better insight into what is going on.
Unfortunately I was unable to reproduce this issue on my VM, so I have to
rely on you to run the test.
Regards,
Hans
[PATCH] Test
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
diff --git a/drivers/media/cec/core/cec-adap.c b/drivers/media/cec/core/cec-adap.c
index 5741adf09a2e..b1951eb7f5bd 100644
--- a/drivers/media/cec/core/cec-adap.c
+++ b/drivers/media/cec/core/cec-adap.c
@@ -935,9 +935,12 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
* Release the lock and wait, retake the lock afterwards.
*/
mutex_unlock(&adap->lock);
- wait_for_completion_killable(&data->c);
- if (!data->completed)
- cancel_delayed_work_sync(&data->work);
+ if (WARN_ON(wait_for_completion_killable_timeout(&data->c, msecs_to_jiffies(adap->xfer_timeout_ms + 1000)) <= 0)) {
+ dprintk(0, "wfc1: %px %d%d%d%d %x\n", adap->kthread_config,
+ adap->is_configuring, adap->is_configured,
+ adap->is_enabled, adap->must_reconfigure, adap->phys_addr);
+ }
+ cancel_delayed_work_sync(&data->work);
mutex_lock(&adap->lock);
/* Cancel the transmit if it was interrupted */
@@ -1563,10 +1566,12 @@ static int cec_config_thread_func(void *arg)
cec_transmit_msg_fh(adap, &msg, NULL, false);
}
}
+ mutex_unlock(&adap->lock);
+ call_void_op(adap, configured);
+ mutex_lock(&adap->lock);
adap->kthread_config = NULL;
complete(&adap->config_completion);
mutex_unlock(&adap->lock);
- call_void_op(adap, configured);
return 0;
unconfigure:
@@ -1592,6 +1597,17 @@ static void cec_claim_log_addrs(struct cec_adapter *adap, bool block)
if (WARN_ON(adap->is_configuring || adap->is_configured))
return;
+ if (adap->kthread_config) {
+ mutex_unlock(&adap->lock);
+// wait_for_completion(&adap->config_completion);
+ if (WARN_ON(wait_for_completion_killable_timeout(&adap->config_completion, msecs_to_jiffies(10000)) <= 0)) {
+ dprintk(0, "wfc2: %px %d%d%d%d %x\n", adap->kthread_config,
+ adap->is_configuring, adap->is_configured,
+ adap->is_enabled, adap->must_reconfigure, adap->phys_addr);
+ }
+ mutex_lock(&adap->lock);
+ }
+
init_completion(&adap->config_completion);
/* Ready to kick off the thread */
@@ -1599,11 +1615,17 @@ static void cec_claim_log_addrs(struct cec_adapter *adap, bool block)
adap->kthread_config = kthread_run(cec_config_thread_func, adap,
"ceccfg-%s", adap->name);
if (IS_ERR(adap->kthread_config)) {
- adap->kthread_config = NULL;
adap->is_configuring = false;
+ adap->kthread_config = NULL;
} else if (block) {
mutex_unlock(&adap->lock);
- wait_for_completion(&adap->config_completion);
+ //wait_for_completion(&adap->config_completion);
+ if (WARN_ON(wait_for_completion_killable_timeout(&adap->config_completion, msecs_to_jiffies(10000)) <= 0)) {
+ dprintk(0, "wfc3: %px %d%d%d%d %x\n", adap->kthread_config,
+ adap->is_configuring, adap->is_configured,
+ adap->is_enabled, adap->must_reconfigure, adap->phys_addr);
+
+ }
mutex_lock(&adap->lock);
}
}
diff --git a/drivers/media/cec/core/cec-api.c b/drivers/media/cec/core/cec-api.c
index 67dc79ef1705..d64bb716f9c6 100644
--- a/drivers/media/cec/core/cec-api.c
+++ b/drivers/media/cec/core/cec-api.c
@@ -664,6 +664,8 @@ static int cec_release(struct inode *inode, struct file *filp)
list_del_init(&data->xfer_list);
}
mutex_unlock(&adap->lock);
+
+ mutex_lock(&fh->lock);
while (!list_empty(&fh->msgs)) {
struct cec_msg_entry *entry =
list_first_entry(&fh->msgs, struct cec_msg_entry, list);
@@ -681,6 +683,7 @@ static int cec_release(struct inode *inode, struct file *filp)
kfree(entry);
}
}
+ mutex_unlock(&fh->lock);
kfree(fh);
cec_put_device(devnode);
next prev parent reply other threads:[~2024-01-30 14:35 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-28 2:33 [Linux Kernel Bugs] KASAN: slab-use-after-free Read in cec_queue_msg_fh and 4 other crashes in the cec device (`cec_ioctl`) Yang, Chenyuan
2023-12-29 6:23 ` Dmitry Vyukov
[not found] ` <SN6PR11MB345527101A2C8A1AC99B04B5FA712@SN6PR11MB3455.namprd11.prod.outlook.com>
2024-01-18 7:52 ` Hans Verkuil
2024-01-19 8:17 ` Hans Verkuil
2024-01-22 19:11 ` Yang, Chenyuan
2024-01-23 8:02 ` Hans Verkuil
2024-01-23 10:39 ` Hans Verkuil
2024-01-24 13:33 ` Yang, Chenyuan
2024-01-25 10:35 ` Hans Verkuil
2024-01-29 3:03 ` Yang, Chenyuan
2024-01-30 14:35 ` Hans Verkuil [this message]
2024-02-12 14:42 ` Hans Verkuil
2024-02-13 15:40 ` Yang, Chenyuan
2024-02-13 16:05 ` Yang, Chenyuan
2024-02-23 14:44 ` Hans Verkuil
[not found] ` <PH7PR11MB5768B0BC3C042A6EA4EC1EF0A0542@PH7PR11MB5768.namprd11.prod.outlook.com>
2024-02-26 12:27 ` Yang, Chenyuan
2024-04-19 14:51 ` Takashi Iwai
2024-04-22 12:14 ` Hans Verkuil
2024-04-22 19:30 ` Takashi Iwai
2024-04-22 15:04 ` Hans Verkuil
2024-04-22 18:54 ` Yang, Chenyuan
2024-04-22 20:57 ` Hans Verkuil
2024-04-29 15:42 ` Yang, Chenyuan
2024-04-30 10:26 ` Hans Verkuil
2024-04-30 17:06 ` Yang, Chenyuan
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