Hi Takashi, On 19/04/2024 16:51, Takashi Iwai wrote: > On Mon, 26 Feb 2024 13:27:16 +0100, > Yang, Chenyuan wrote: >> >> Hi Hans, >> >> Thank you for your continued efforts in investigating this bug and implementing the new patch! >> >> Regarding the two warnings, they have been addressed by this new patch and are no longer reproducible. Additionally, I conducted a 48-hour fuzzing test on the CEC driver, which has successfully eliminated the previous hanging issue. >> >> One thing to note that the system will now log timeout events: >> ``` >> [ 2281.265385][ T2034] cec-vivid-001-vid-out0: transmit timed out >> [ 2282.994510][ T2017] cec-vivid-000-vid-cap0: transmit timed out >> [ 2283.063484][ T2050] cec-vivid-002-vid-out0: transmit timed out >> [ 2283.073468][ T2065] cec-vivid-003-vid-cap0: transmit timed out >> [ 2283.373518][ T2033] cec-vivid-001-vid-cap0: transmit timed out >> [ 2285.113544][ T2018] cec-vivid-000-vid-out0: transmit timed out >> [ 2285.193502][ T2050] cec-vivid-002-vid-out0: transmit timed out >> [ 2285.193570][ T2065] cec-vivid-003-vid-cap0: transmit timed out >> [ 2285.513570][ T2033] cec-vivid-001-vid-cap0: transmit timed out >> ``` >> >> Best, >> Chenyuan > > Hi Hans, > > how is the current status of this bug fix? It seems that the thread > stalled, and I wonder how we can go further. > > I'm asking it because CVE-2024-23848 was assigned and we've been asked > about the bug fix. I missed this reply, so I will take another look at the patch. Too many emails :-( Two other patches relating to this I have just posted: https://patchwork.linuxtv.org/project/linux-media/patch/2b043325-14c0-4e63-ae9c-0d685d96fd98@xxxxxxxxx/ https://patchwork.linuxtv.org/project/linux-media/patch/f17f961b-3a19-48da-941a-c8970d9e1786@xxxxxxxxx/ Regards, Hans > > > Thanks! > > Takashi > >> >> From: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> >> Date: Friday, February 23, 2024 at 8:44 AM >> To: Yang, Chenyuan <cy54@xxxxxxxxxxxx>, linux-media@xxxxxxxxxxxxxxx <linux-media@xxxxxxxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx <linux-kernel@xxxxxxxxxxxxxxx> >> Cc: jani.nikula@xxxxxxxxx <jani.nikula@xxxxxxxxx>, syzkaller@xxxxxxxxxxxxxxxx <syzkaller@xxxxxxxxxxxxxxxx>, mchehab@xxxxxxxxxx <mchehab@xxxxxxxxxx>, Zhao, Zijie <zijie4@xxxxxxxxxxxx>, Zhang, Lingming <lingming@xxxxxxxxxxxx> >> 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`) >> Hi Chenyuan, >> >> Here is another patch for you to try. I think it is good for blocking CEC_ADAP_S_LOG_ADDRS >> ioctl calls, but if the filehandle is in non-blocking mode, I'm still not certain it >> is correct. But one issue at a time :-) >> >> Regards, >> >> Hans >> >> diff --git a/drivers/media/cec/core/cec-adap.c b/drivers/media/cec/core/cec-adap.c >> index 559a172ebc6c..a493cbce2456 100644 >> --- a/drivers/media/cec/core/cec-adap.c >> +++ b/drivers/media/cec/core/cec-adap.c >> @@ -936,8 +936,7 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg, >> */ >> mutex_unlock(&adap->lock); >> wait_for_completion_killable(&data->c); >> - if (!data->completed) >> - cancel_delayed_work_sync(&data->work); >> + cancel_delayed_work_sync(&data->work); >> mutex_lock(&adap->lock); >> >> /* Cancel the transmit if it was interrupted */ >> @@ -1575,9 +1574,12 @@ static int cec_config_thread_func(void *arg) >> */ >> static void cec_claim_log_addrs(struct cec_adapter *adap, bool block) >> { >> - if (WARN_ON(adap->is_configuring || adap->is_configured)) >> + if (WARN_ON(adap->is_claiming_log_addrs || >> + adap->is_configuring || adap->is_configured)) >> return; >> >> + adap->is_claiming_log_addrs = true; >> + >> init_completion(&adap->config_completion); >> >> /* Ready to kick off the thread */ >> @@ -1592,6 +1594,7 @@ static void cec_claim_log_addrs(struct cec_adapter *adap, bool block) >> wait_for_completion(&adap->config_completion); >> mutex_lock(&adap->lock); >> } >> + adap->is_claiming_log_addrs = false; >> } >> >> /* >> diff --git a/drivers/media/cec/core/cec-api.c b/drivers/media/cec/core/cec-api.c >> index 67dc79ef1705..3ef915344304 100644 >> --- a/drivers/media/cec/core/cec-api.c >> +++ b/drivers/media/cec/core/cec-api.c >> @@ -178,7 +178,7 @@ static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh, >> CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU | >> CEC_LOG_ADDRS_FL_CDC_ONLY; >> mutex_lock(&adap->lock); >> - if (!adap->is_configuring && >> + if (!adap->is_claiming_log_addrs && !adap->is_configuring && >> (!log_addrs.num_log_addrs || !adap->is_configured) && >> !cec_is_busy(adap, fh)) { >> err = __cec_s_log_addrs(adap, &log_addrs, block); >> @@ -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); >> diff --git a/include/media/cec.h b/include/media/cec.h >> index 10c9cf6058b7..cc3fcd0496c3 100644 >> --- a/include/media/cec.h >> +++ b/include/media/cec.h >> @@ -258,6 +258,7 @@ struct cec_adapter { >> u16 phys_addr; >> bool needs_hpd; >> bool is_enabled; >> + bool is_claiming_log_addrs; >> bool is_configuring; >> bool must_reconfigure; >> bool is_configured; >>
