Hi Hans, Thanks so much for your prompt response! This patch does fix the error and there is no "transmit timed out" message anymore! (Sorry I replied this twice since I forgot to turn on the plain text mode in my first reply.) Best, Chenyuan On 4/30/24, 3:26 AM, "syzkaller@xxxxxxxxxxxxxxxx <mailto:syzkaller@xxxxxxxxxxxxxxxx> on behalf of Hans Verkuil" <syzkaller@xxxxxxxxxxxxxxxx <mailto:syzkaller@xxxxxxxxxxxxxxxx> on behalf of hverkuil-cisco@xxxxxxxxx <mailto:hverkuil-cisco@xxxxxxxxx>> wrote: Hi Chenyuan, On 29/04/2024 17:42, Yang, Chenyuan wrote: > Hi Hans, > > Here is my QEMU booting command: > > ``` > qemu-system-x86_64 \ > -m 2G \ > -smp 2 \ > -kernel linux/arch/x86/boot/bzImage \ > -append "console=ttyS0 root=/dev/sda earlyprintk=serial net.ifnames=0" \ > -drive file=image/bullseye-qemu.img,format=raw \ > -net user,host=10.0.2.10,hostfwd=tcp:127.0.0.1:10021-:22 \ > -net nic,model=e1000 \ > -enable-kvm \ > -nographic \ > -pidfile vm.pi > ``` > > Plus, here is the config of vivid from my linux kernel building config: > > ``` > CONFIG_VIDEO_VIVID=y > CONFIG_VIDEO_VIVID_CEC=y > CONFIG_VIDEO_VIVID_MAX_DEVS=64 > > CONFIG_CMDLINE="... vivid.n_devs=16 vivid.multiplanar=1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2 ..." > > # Here is the full > CONFIG_CMDLINE="earlyprintk=serial net.ifnames=0 sysctl.kernel.hung_task_all_cpu_backtrace=1 ima_policy=tcb nf-conntrack-ftp.ports=20000 nf-conntrack-tftp.ports=20000 nf-conntrack-sip.ports=20000 nf-conntrack-irc.ports=20000 nf-conntrack-sane.ports=20000 binder.debug_mask=0 rcupdate.rcu_expedited=1 rcupdate.rcu_cpu_stall_cputime=1 no_hash_pointers page_owner=on sysctl.vm.nr_hugepages=4 sysctl.vm.nr_overcommit_hugepages=4 secretmem.enable=1 sysctl.max_rcu_stall_to_panic=1 msr.allow_writes=off coredump_filter=0xffff root=/dev/sda console=ttyS0 vsyscall=native numa=fake=2 kvm-intel.nested=1 spec_store_bypass_disable=prctl nopcid vivid.n_devs=16 vivid.multiplanar=1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2 netrom.nr_ndevs=16 rose.rose_ndevs=16 smp.csd_lock_timeout=100000 watchdog_thresh=55 workqueue.watchdog_thresh=140 sysctl.net.core.netdev_unregister_timeout_secs=140 dummy_hcd.num=8 kmsan.panic=1" > ``` > > Plus, I attached the current patch (git diff > patch). > > Let me know if you need any further information. Ah, that was helpful. I also discovered that I had to run the reproducer as root, that helped too :-) Please add this patch on top of the diff you already have and try again. The reproducer kills each forked process after 5 seconds from what I can tell. That causes a driver wait call to return -ERESTARTSYS, and that corner case was not handled correctly. It caused the harmless but confusing "transmit timed out" message. Regards, Hans --------------------------------------------------------------------- [PATCH] cec: core: avoid confusing "transmit timed out" message If, when waiting for a transmit to finish, the wait is interrupted, then you might get a "transmit timed out" message, even though the transmit was interrupted and did not actually time out. Set transmit_in_progress_aborted to true if the wait_for_completion_killable() call was interrupted and ensure that the transmit is properly marked as ABORTED. Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx <mailto:hverkuil-cisco@xxxxxxxxx>> --- drivers/media/cec/core/cec-adap.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/media/cec/core/cec-adap.c b/drivers/media/cec/core/cec-adap.c index a493cbce24567..da09834990b87 100644 --- a/drivers/media/cec/core/cec-adap.c +++ b/drivers/media/cec/core/cec-adap.c @@ -490,6 +490,15 @@ int cec_thread_func(void *_adap) goto unlock; } + if (adap->transmit_in_progress && + adap->transmit_in_progress_aborted) { + if (adap->transmitting) + cec_data_cancel(adap->transmitting, + CEC_TX_STATUS_ABORTED, 0); + adap->transmit_in_progress = false; + adap->transmit_in_progress_aborted = false; + goto unlock; + } if (adap->transmit_in_progress && timeout) { /* * If we timeout, then log that. Normally this does @@ -771,6 +780,7 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg, { struct cec_data *data; bool is_raw = msg_is_raw(msg); + int err; if (adap->devnode.unregistered) return -ENODEV; @@ -935,10 +945,13 @@ 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); + err = wait_for_completion_killable(&data->c); cancel_delayed_work_sync(&data->work); mutex_lock(&adap->lock); + if (err) + adap->transmit_in_progress_aborted = true; + /* Cancel the transmit if it was interrupted */ if (!data->completed) { if (data->msg.tx_status & CEC_TX_STATUS_OK) -- 2.43.0 -- You received this message because you are subscribed to a topic in the Google Groups "syzkaller" group. 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